februar 16, 2023 by Paul - Legacy Tree Genealogists Researcher 11 Comments

How to Understand Your Closest Autosomal DNA Test Matches

This article is based on a similar article from the January – March 2022 issue of NGS Magazine and is reprinted here with permission. We hope it helps you know how to better understand your autosomal DNA Test matches and what it means for you.

Autosomal DNA test results at the major genetic genealogy testing companies (23andMe, Ancestry, Family Tree DNA, LivingDNA, MyHeritage) include two main elements: ethnicity admixture estimates and genetic cousin match lists. Ethnicity estimates are a central focus of companies’ marketing efforts and a significant motivation for many testers (maybe you took a DNA test to find out your ethnicity). They can provide important context for genealogical investigation. However, genetic cousin match lists are the more useful element of autosomal DNA test results for solving family history mysteries and answering long-standing questions about a family tree.

Reviewing the closest genetic cousins in your autosomal DNA test matches list can help confirm the biological accuracy of close proposed genealogical relationships, provide a framework for interpreting more distant genetic relationships and guide future targeted testing efforts. Meanwhile, close genetic relationships to unknown relatives, lower than expected amounts of shared DNA with your known relatives, or a lack of genetic connections to your known tested relatives can signal the possibility of misattributed parentage – a topic we recently discussed here.

How do companies create and prioritize your autosomal DNA test match lists?

Your genetic cousin match lists are created by comparison of your DNA markers against the DNA markers of other customers in a company’s database. Autosomal DNA tests analyze several hundred thousand locations (known as SNPs) across each customer’s genome. For each location queried, the raw data of the test results report two base-pair values: one maternal and one paternal.

When you and someone else in a company’s database share the same marker values on at least one chromosome copy over several hundred consecutive SNPs, it is assumed you share a chunk or segment of DNA. The longer this chunk of DNA, the more likely it is that you and your genetic cousin inherited it from a recent common ancestor. A range of possible or likely relationships is estimated based on the size, position, and number of segments you and your match share.

The raw data files for these two individuals show that they share at least one of their two markers at each location queried on chromosome 1 over the course of several consecutive markers. This pattern
continues for an additional few thousand markers and represents a shared segment of DNA.

DNA testing companies most often prioritize the order of genetic cousins in their lists based on the total number of centimorgans your genetic cousins share with you. Centimorgans are a measurement unit expressing the likelihood of recombination between two locations on a chromosome over a single generation.

As this likelihood of recombination is dependent on the segment’s location on a chromosome and several other factors, there is not a consistent conversion between the length and centimorgan value of a segment. Closer genetic relatives share higher total centimorgan amounts in more clearly defined ranges than more distant genetic relatives.

For example, parents and children will share around 3400 cM (with slight variation depending on the company). Siblings most often share between 2200 and 3020 cM, and if your genetic cousin shares between 2400 cM and 3100 cM, they are almost certainly a full sibling. Half-siblings, aunts, uncles, nieces, and nephews most often share between about 1340 and 2150 cM, and if your genetic cousin shares between 1550 and 1960 cM with you, they are almost certainly related as a half-sibling, aunt, uncle, nephew or niece.

This chart from The Shared cM Project shows the ranges and averages of total shared centimorgans for various relationship levels. The source for this data comes from collaborative data collection from
genealogists who report data regarding known relationships. An interactive version of this chart is available through DNAPainter.com. Image courtesy of Blaine T. Bettinger, thegeneticgenealogist.com,
CC 4.0 Attribution License.

Beyond these relationship levels, ranges of observed and expected amounts of shared DNA overlap more, making the relationship level more ambiguous based on the number of total shared cM between you and your matches. Genetic cousins sharing 600 cM with you might be related as a first cousin, half-first cousin, or first cousin once removed. As the number of shared cMs between you and your genetic cousins decreases, possible relationships increase. While a genetic cousin sharing 600 cM could be related as a first cousin or a first cousin once removed, the number of possibilities is limited to a relationship within four to five generational steps. Meanwhile, a genetic cousin sharing 40 cM could be related anywhere from second to distant cousins.

Each of the major genetic genealogy testing companies includes a genetic cousin match list as part of their autosomal DNA test results like the ones pictured above from AncestryDNA. As part of initial efforts to analyze and interpret these results, we recommend starting with the closest genetic cousins sharing more than 200 cM. These lists often include a section for each match detailing how much DNA
they share with the test taker.

Each company provides broad relationship category estimates based on the total number of centimorgans you share with particular genetic cousins. Resources for more fine-tuned estimates are available through “The Shared cM Project” and DNA Painter’s “The Shared cM Project 4.0 tool v4.”

Blaine Bettinger, “The Shared cM Project,” The Genetic Genealogist (Blog), https://thegeneticgenealogist.com/: accessed November 2021; and,

Jonny Perl, DNA Painter, “The Shared cM Project 4.0 tool v4,” https://dnapainter.com/tools/sharedcmv4: accessed November 2021; and,

Jonny Perl, DNA Painter, “The Shared cM Project 4.0 tool v4 beta,” h https://dnapainter.com/tools/sharedcmv4-beta: accessed November 2021.

Evaluation of Closest Genetic Cousins (Over About 200 cM) Using Autosomal DNA Test Matches

If you are beginning to explore your genetic test results, consider starting by analyzing your closest genetic cousins, who share more than 200 centimorgans (about 2.7% at 23andMe). Individuals sharing higher than this amount of DNA are most often related at a level closer than third cousins. Therefore, it is likely that the nature of their relationship to you and your common ancestors’ identities can be determined.

This histogram from the Shared cM project shows the distribution of total amounts of shared DNA between test takers and known aunts, uncles, nieces or nephews. When analyzing total centimorgans shared with known relatives, researchers should consult the relationship probabilities at DNA Painter.
Not only should they determine if the reported total is possible, but they should also consider if the reported total is likely given the proposed relationship, They might also consider whether a half relationship or other relationship is more likely. Image courtesy of Blaine T. Bettinger,
thegeneticgenealogist.com, CC 4.0 Attribution License.

For analysis of closest genetic cousins, consider the following questions:

Do you recognize any of your closest autosomal DNA test matches?

After taking a DNA test, you may be pleasantly surprised to find siblings, aunts, uncles, first cousins, and other close relatives who have already done DNA testing. Even if you do not personally know some of these closest matches, you may find them through a study of attached family trees, collaboration with genetic cousins, or researching the identity of your match and how you are related.

Do your matches have surnames or family trees that clarify their likely relationship?

Even if your match list does not include close recognizable genetic cousins, it might include individuals with surnames from different branches of your family tree, familiar names of distant collateral relatives, or individuals whose family trees aid in the identification of shared ancestors or surnames.

Do your close-known relatives share appropriate amounts of DNA?

Even if your known relatives appear in your match list, there is still more work to do. Do your known relatives or genetic cousins with common ancestors share appropriate amounts of DNA, given their proposed relationships?

Do your first cousins share amounts of DNA appropriate for first cousins, or could they be half-first cousins?

These questions might be answered by utilizing the tools and resources at DNA Painter and the Shared cM Project.

If your known relatives share amounts of DNA more typical of half relationships, you should perform additional research to determine if you, your genetic cousin, or both of you have a case of misattributed parentage somewhere in your ancestral line. You should also explore the possibility that a full relationship is still possible, but the amount of shared DNA is just low or high, given your proposed relationship.

Do you have too many close autosomal DNA test matches?

In some situations, you might have hundreds of close DNA matches sharing more than 200 cM. This can happen if your ancestors lived in an endogamous population where a population’s isolation due to language, culture, religion, or geography resulted in many generations of intermarriage. As a result, your genetic cousins may share multiple sets of common ancestors with you, or you may descend from the same common ancestors numerous times. Both scenarios can result in higher amounts of shared DNA than expected, given your closest genealogical relationship to a genetic cousin. Other situations where you might have many matches can occur when your ancestors were members of very large families. In these scenarios, it may be wise to focus on your matches sharing the most DNA and analyzing those relationships first.

Do you have no close matches?

Other times, test takers may not have any close genetic cousins sharing more than 200 cM. Alternatively, they may not have close matches from one of their proposed ancestral lines. If this describes your match list, more information is needed before you jump to a hasty conclusion of misattributed parentage. It may be that your other family members have not yet performed DNA testing either because you descend from a line of small families with few descendants or your ancestors came from a geographic area that is underrepresented in the database. To confirm the biological accuracy of the first few generations of your proposed genealogy, targeted testing or confirmation of previous testing of documented relatives from various ancestral lines may be necessary.

When the close-known relatives in your match list share appropriate amounts of DNA given their proposed relationships, the identities and relationships of these individuals may aid in efforts to interpret and understand the relationships to your more distant genetic cousins through shared match relationships. They might help isolate potentially pertinent genetic cousins from an ancestral line of interest in the context of a specific research question and objective. On the other hand, a lack of close matches raises possibilities for targeted testing of your known relatives.

Alternatively, reviewing your close genetic cousins may result in the discovery of surprise relationships. Perhaps you do not share DNA with close family members known to have tested. Maybe you have no strong genetic connections to cousins from a particular ancestral line. Given proposed relationships with known relatives, you may share less DNA than expected. Maybe you have close genetic cousins who have no known or documented relationship with you. Each of these situations can signal a case of misattributed parentage either for you or your DNA matches. If this is the case, explore this possibility with the guidance of our recent article.

If you have specific questions about your autosomal DNA test match results and would like to have a free consultation with one of our experts, you can fill out our contact form here.

januar 4, 2023 by Paul - Legacy Tree Genealogists Researcher 4 Comments

6 Signs of Misattributed Parentage in Your Genetic Family Tree

While DNA testing and genetic evidence are certainly useful for breaking down challenging historic brick walls, the implications of DNA testing can also hit closer to home in the modern era when it comes to research on misattributed parentage. 

In cases of adoption, unknown parentage or misattributed parentage, genetic genealogy methodologies enable identification of close biological ancestors whose identities might otherwise remain unknown, and which represent immediate brick walls for any genealogist dealing with such a scenario in their immediate family tree.

In this series of blog posts, we explore tips for successful genetic genealogy searches dealing with adoption research, unknown parentage, or misattributed parentage.

(Portions of this article are reprinted with permission from the April-June 2022 issue of NGS Magazine )

Genetic genealogy can (and often does) reveal surprise cases of misattributed parentage in test takers’ family trees. Misattributed parentage or ancestry, where a presumed parent is not the biological parent of an individual or their ancestor, is quite common. Rates of misattributed paternity are estimated to be between 2% and 12% and may vary between populations.1 These rates are based on studies of populations during the 20th and 21st century and may not necessarily be representative of historic rates of misattributed parentage. Even so, exploration of what the low end of this range of rates might mean for an individual’s genealogy is informative.

Even with a conservative estimate of 2% probability of a misattributed parentage event per generational linkage, this suggests that approximately 13% of individuals in the general population will have at least one case of misattributed parentage in the first three generations of their family tree (for themselves, a parent, or a grandparent).

Under even more conservative estimates (.5% probability of a misattributed parentage even per generational linkage), most people will have at least one case of misattributed parentage in the first eight generations of their family tree (up to the sixth great grandparent level). Based on this, even if you can document your family tree several generations, it is still a good idea to verify that those documented relationships reflect biological reality using genetic genealogy.

Genetic genealogy test results often provide the initial clues to uncover a misattributed parentage event. These events may even go undetected unless DNA test results are analyzed carefully.

Once a case of misattributed parentage has been detected and confirmed, genetic genealogy can also aid in determining the identity of a biological parent, either for you or one of your ancestors.

Following are some of the telltale signs or clues that you may have a case of misattributed parentage in your family tree, along with some tips of what to do next to determine the identities of biological ancestors.

Clue #1 Unexpected Ethnicity Results

The first clue that you or a close ancestor may have had misattributed parentage could be anomalous ethnicity admixture estimates at one of the major DNA testing companies.

Each company analyzes thousands of DNA markers and determines which combinations of those markers are most likely found in regions around the world. As such they can estimate where some of your recent ancestors lived or came from. Increasingly, companies are not only offering broad ethnicity estimates for larger regions (where ancestors may have lived in the last several hundred to thousand years) but they are also supplementing these reports with specific regions, groups, or migration patterns where a test taker’s ancestors likely lived in the last few hundred years. For more information on how this works, see our article on ethnicity admixture estimates.

Small amounts of ethnicity admixture from populations near to where your ancestors lived are common and even expected, but if you have significant percentages (higher than 5-10%) of ethnicity admixture from unexpected regions and you also have genetic connections to unexpected communities, groups or migration groups, this could suggest misattributed parentage somewhere in your tree.

The size of the unexpected percentage might help you estimate where the misattributed parentage occurred. For example, if your documented family tree is entirely British and you find surprise Jewish admixture, 50% might suggest that you have misattributed parentage, 25% might suggest that one of your parents has misattributed parentage, and 12% might suggest that one of your grandparents has misattributed parentage.

PRO TIP:

Before assuming anomalous ethnicity admixture estimate means misattributed parentage, test at a few major DNA testing companies. Each company maintains its own reference panel, and analytical algorithms for estimating ethnicity. By testing at multiple companies and paying attention to the overarching patterns, it is possible to get a better and more accurate idea of your ethnic origins. If the anomalous result persists across multiple companies, explore the possibility of misattributed ancestry further. Learn how to create your DNA Testing Plan.

Clue #2 Y-DNA Testing Anomalies

Another sign that you might have misattributed parentage at some point in your family tree is if Y-DNA testing uncovers anomalous connections or a lack of connections to expected family members.

Y-DNA (or the Y-chromosome) is the male sex chromosome and is passed from generation to generation in a pattern of direct-line paternal inheritance. Only males inherit a Y-chromosome. Therefore, it follows the same inheritance pattern as surnames in many western civilizations.

When males perform Y-DNA testing at Family Tree DNA, they can sometimes connect with other males who are related along their direct patriline. Sometimes these individuals are close relatives, related within a genealogical timeframe. Other times, these Y-DNA matches are distant relatives whose common ancestors lived before the advent of heritable surnames.

If you take a Y-DNA test and find no Y-DNA matches, it may be that other direct paternal relatives have not yet performed DNA testing.

If you believe other direct paternal relatives have performed DNA testing and you are not matching them, it could indicate that you or they have misattributed parentage somewhere along the direct paternal line.

If you have Y-DNA matches to many individuals with a different shared surname this could mean any of the following:

You could have misattributed parentage on your direct paternal line.
It may be that those relatives are descended from a common ancestor who had misattributed parentage or unknown parentage from direct paternal ancestors with a different surname.
And/or perhaps direct paternal relatives from your distant paternal ancestors have not yet performed DNA testing.

PRO TIP:

If you have Y-DNA test result anomalies, consider target testing known relatives who also descend from your proposed direct paternal ancestors. This can help you pinpoint the generation in which a case of misattributed parentage might have occurred. It can also help you determine if there is a case of misattributed parentage along your direct paternal line or if there might be other explanations for your lack of Y-DNA matches, or unexpected Y-DNA matches.

Clue #3 No shared DNA with close relatives who have also tested

A lack of shared DNA with a close relative who you know (or who you believe) also performed DNA testing can also be a sign of misattributed parentage or ancestry (either for you, or your known relative).

All relatives within the range of second cousins should share at least some DNA with each other. If a known sibling, first cousin, or second cousin has performed DNA testing and is not showing in your match list then ensure that the following are true:

The relative did indeed take and submit the DNA test.
The relative performed DNA testing at the same company where you also tested (companies maintain separate databases, so if a known cousin tests with a different company they will not appear as a match).
The relative has opted into DNA matching (some companies offer the option of performing an autosomal DNA test to obtain ethnicity estimates or other reports, but permit opting out of DNA matching).
The relative’s test results have completed processing (sometimes there is a delay in a cousin showing up in the match lists of others if their test results have just recently completed processing).
The relative is not using an alias or unidentifiable username (sometimes the cousin may be in your match list, but under a username that you do not recognize).

If all the above is true, then there may be a case of misattributed parentage for you or for your known relative. To determine which individual does not descend from the proposed common ancestors, consider the matches in each individual’s genetic test results.

Example Cousin Scenario 1 and 2

Imagine that you took a DNA test along with your paternal first cousin, Sharon. You are both proposed grandchildren of Paul and Helen Smith. When the test results complete processing, you find that you do not share DNA with Sharon. In this situation there are two main possible scenarios. Either you are not a descendant of Paul and Helen Smith (scenario 1), or Sharon is not a descendant of Paul and Helen Smith (scenario 2).

If you share DNA with other descendants or collateral relatives of Paul and Helen Smith, while Sharon does not, you can conclude that Sharon is not a biological descendant of Paul and Helen (scenario 1).
If Sharon shares DNA with descendants or collateral relatives of Paul and Helen which you do not match, then you are not a biological descendant of Paul and Helen (scenario 2).

In this case, it is also possible that neither of you descends from Paul and Helen or that one of you descends from the couple but there are no other tested descendants or collateral relatives. Those scenarios would require additional analysis and exploration.

Scenario 1: You do not share DNA with your proposed paternal first cousin, Sharon (red). You do share DNA with other documented first cousins and collateral relatives of your grandparents at appropriate levels (green) while Sharon does not. In this case, you can conclude that Sharon is not the biological granddaughter of Paul and Helen Smith. Either she is not the biological daughter of Susan, or Susan is not the biological daughter of Paul and Helen Smith.

Note that lack of shared DNA between known relatives strongly indicates a case of misattributed parentage for individuals who are expected to be related within the range of close family to second cousins. More distant relatives in the range of second cousins once removed to more distant relatives may have simply inherited different portions of their shared ancestors’ DNA and may not share DNA with each other.

PRO TIP:

To determine if this is the case for more distant known relatives, determine if you and your matches share DNA with other descendants or collateral relatives of the proposed common ancestors.

Clue #4 Lower than expected amounts of shared DNA with a known relative

Sharing significantly less DNA with a known relative than expected is another sign of possible misattributed parentage. If your known relative shares half the amount of DNA than would be expected given their proposed relationship, it may be that they are a half rather than a full relative.

To evaluate this possibility, utilize the evaluation tools through DNA Painter and the Shared cM Project to evaluate the amount of shared DNA.2

On the one hand, just because a proposed relationship is possible does not necessarily mean that it is likely. If a known relative is sharing a low amount of DNA explore the possibility of a half relationship.

On the other hand, some relatives just happen to share low amounts of DNA, and although there may be a small probability of a proposed relationship, someone must make up the 5% probability for specific relationship levels.

PRO TIP:

To determine if your known relative is a half-relative or to determine if they are just a low sharing full relative, explore the matches shared between you and them to determine if shared cousins include collateral relatives of both of your proposed common ancestors or only one of them.

Example Cousin Scenario 3, 4, 5

Imagine a different situation where you and your first cousin, Sharon, both perform DNA testing at the same testing company. When the results complete processing, you are found to share just 550 centimorgans with each other.

According to DNA Painter’s Shared cM Project 4.0 tool, this amount of shared DNA is much more likely between half first cousins (about 80-90% probability) than it is between full first cousins (about 10-20% probability).

In this situation there are three main possible scenarios:

You are a descendant of Paul and Helen Smith while Sharon is a descendant of only Paul or Helen (scenario 3)
Sharon is a descendant of Paul and Helen Smith while you are a descendant of only Paul or Helen (scenario 4)
Both of you are descendants of Paul and Helen but happen to share a low amount of DNA with each other given your proposed relationship (scenario 5).

If you have genetic cousins who are related through the ancestry of both Paul and Helen, while Sharon only has genetic cousins who are related through Helen and shares consistently low amounts of DNA with other descendants of Paul and Helen then you can conclude Sharon’s parent was not the biological child of Paul but was the child of Helen (scenario 3).

If Sharon has genetic cousins who are related through the ancestry of both Paul and Helen, while you only have genetic cousins who are related through Helen and you share consistently low amounts of DNA with other descendants of Paul and Helen, then you can conclude that your parent was not a biological child of Paul but was the biological child of Helen (scenario 4).

If both you and Sharon have genetic cousins who are related through the ancestry of both Paul and Helen, then you can conclude that you and Sharon are full first cousins but simply share low amounts of DNA given your proposed relationship (scenario 5).

Scenario 4: You share 550 cM of DNA with your paternal first cousin Sharon – an amount of DNA more typical of half first cousin relationships (orange). You share consistently low amounts of DNA with other descendants of Paul and Helen (orange) while Sharon shared appropriate amounts of DNA with the same individuals. Both you and Sharon share DNA with collateral relatives of your grandmother, Helen (green). While Sharon shares DNA with collateral relatives of Paul, you do not (red). In this case, you can conclude that your father, David, was not the biological son of Paul.

Clue #5 Close unknown genetic cousins

Another hallmark of cases of misattributed parentage is the presence of close genetic cousins (those sharing more than 200 cM) for whom no known or documented relationship can be determined in the context of your documented family tree or their documented family tree.

To determine whether you or your match have a case of misattributed parentage in your respective family trees, it is useful in these cases to consider the matches shared between you and the match to determine which family tree those shared matches support.

Example Cousin Scenario 6, 7

Imagine that you have a close genetic cousin, Mary, sharing 600 cM who has an extensive six-generation family tree associated with her test results. Based on the amount of DNA you share with each other; Mary should be related in the range of a first cousin to first cousin once removed.

You could have a case of misattributed parentage in your family tree and may biologically descend from Mary’s ancestors (scenario 6).
Mary could have a case of misattributed parentage in her family tree and could biologically descend from your ancestors (scenario 7).
Alternatively, you could both have cases of misattributed parentage in your trees and may descend from a shared common ancestor that is unknown to either of you (scenario 8).

If your shared matches to Mary are known descendants and collateral relatives of your paternal grandparents, Paul and/or Helen Smith, then we can conclude that Mary is also descended from Paul and/or Helen or one of their collateral relatives and that she has a case of misattributed parentage in her family tree (scenario 6).

Meanwhile, if your shared matches with Mary are all descended from a set of Mary’s second great grandparents, this would indicate that you are also descended from this same couple and that you have a case of misattributed parentage in your family tree (scenario 7).

If all shared matches between you and Mary do not have clear relationships to your respective proposed family trees, but instead form their own cluster of known relatives from a completely different couple, then it may be that both you and Mary have cases of misattributed parentage in your family trees (scenario 8).

Scenario 6: You have a close mystery genetic cousin, Mary, who has an extensive family tree associated with her test results, but no documented shared ancestors (yellow). You share 600 cM of DNA with each other which is typical of a first cousin, or first cousin once removed level of relationship. Mary shares DNA with other descendants and collateral relatives of both Paul and Helen Smith. In this case, you can conclude that Mary is also a descendant of Paul and Helen and has a case of misattributed parentage in recent generations of her family tree.

Clue #6 No genetic connections to a particular branch of your family

One additional clue that can signal a case of misattributed parentage is when your match list lacks representation of collateral relatives through a proposed ancestral line.

However, you should exercise caution in these situations to avoid jumping to a hasty conclusion. In this case, absence of evidence is not necessarily evidence of absence. Just because there are no matches from a particular line does not necessarily mean that you are not biologically descended from that family. Consider the following reasons there may be no genetic connections to a particular branch of your family.

Unrepresented family lines might be composed of several generations of small families that only had one or two children resulting in few living descendants to test in the first place.
Underrepresented families might be composed of recent immigrants from countries, regions and populations which are not well sampled in the database.
In other cases, family members from that line may not have performed DNA testing yet.

In these situations, it is useful to consider the family sizes, geographic origins, and other family details for the ancestral line that is missing in your test results.

If a lack of representation from a particular line accompanies one of the scenarios discussed above (no relationship to a known tested relative, lower than expected amounts of shared DNA with known relatives, or multiple genetic cousins with a documented relationship to each other but not to the test subject), then a case of misattributed parentage is likely.

Even so, the best way to explore the anomaly of missing representation is to target test relatives from that family line in order to test the hypothesis that the lack of matches is due to misattributed parentage at some point along that ancestral line rather than low testing representation from that family in the database.

Imagine that in your case, you have many matches who are related through the ancestry of your maternal grandparents, as well as many matches through the ancestry of your paternal grandmother, but you cannot identify any matches who are related through the ancestry of your paternal grandfather Paul Smith.

If Paul Smith was from a family of ten children and descended from a long line of large families in Colonial America, we might expect there to be at least some matches through this proposed ancestral line. Meanwhile, if Paul was the only child of an only child of an only child and was an immigrant from Germany (where DNA testing is not as prevalent), then the lack of genetic cousins from that ancestral line is more likely due to small family sizes and recent immigration from an underrepresented population in the testing databases.

In either case, targeted testing of a documented relative could help confirm or refute the possibility of a case of misattributed parentage.

What Next?

While none of these signs in isolation or combination are proof of a case of misattributed parentage, if your test results fit one or more of these descriptions, it may be wise to at least consider the possibility of misattributed parentages somewhere in your family tree.

If you come across DNA test results that are anomalous because of ethnicity admixture, Y-DNA anomalies, lack of matching to known relatives, low amounts of shared DNA with known relatives, close genetic relationships to unknown relatives, or a lack of genetic connections to relatives from a particular branch in your family tree, use the tips in this article to pinpoint where a case of misattributed parentage may have occurred and then determine who your biological ancestors were.

If you need help, or even just want someone to review your work to make sure that you are correct in your conclusions, hire a professional genealogist at Legacy Tree to help you explore your biological heritage.

december 19, 2022 by Paul - Legacy Tree Genealogists Researcher Leave a Comment

Nine Tips for Successful Adoption Research with Genetic Genealogy

In this series of blog posts, we explore tips for successful genetic genealogy searches dealing with adoption research, unknown parentage, or misattributed parentage.

Approximately 7 million Americans (or 2% of the population) are adopted, and about 140,000 children are adopted each year. Meanwhile, nearly 60% of the U.S. population has had a personal experience with adoption, meaning that they themselves, a family member, or a close friend was adopted, had adopted a child, or had placed a child for adoption.[1] Though the statistics, processes, and documentation may vary, adoption is a common practice in many countries around the world. As a result, many genealogy researchers have recent obstacles in their family trees due to cases of adoption either for themselves or their immediate ancestors.

Genetic genealogy research is an important research avenue for adoptees or their descendants seeking to learn more about their biological ancestry. Even so, researchers should recognize document research avenues that might aid in the effort. Following are nine tips for using documentary and genetic evidence to identify biological parents in a case of recent adoption.

1. Gather as much background information, context, and records as you can to start your adoption research

To successfully identify an adoptee’s biological parents, it is first essential to obtain as much information as possible regarding the context of the adoptee’s conception and birth. This often involves seeking as much documentary evidence as possible.

Interview Those Involved

Individuals involved in the adoption process might be interviewed. The adoptee themselves may have heard information from their adoptive parents. Adoptive parents may be able to share some information regarding the biological parents. If adoptive parents are deceased or are unwilling to share information or if they do not have information to share, there are still some documentary research avenues that might be pursued.

Request Records

Depending on the state, adoptees, and in some cases their immediate family members, may be entitled to original birth certificates, non-identifying information from the adoption agency or the court that handled the adoption, or even the adoption file itself. These records can be immensely helpful for learning information about biological parents and their extended families. Even if non-identifying information was obtained previously, it may be worth requesting again as what is considered non-identifying can be subject to the interpretation of the worker handling the request. Also, an adoptee might consider working with a mutual consent registry to possibly connect with a biological parent. Some states sponsor an official registry, and other organizations maintain some registries.

In some international adoptions, records from the courts or agencies that processed the adoption can sometimes be obtained. Additional documents that might be sought include immigration records, naturalization records, passports, orphanage records, and original civil registration records from the country where an adoptee was born.

Request Records for non-identifying information

Historic Adoption

If researching a historic adoption, keep in mind that confidentiality was not applied to adoption records until about 1920. If an adoption occurred prior to widespread sealed/closed adoption laws, there may be public records relating to an adoption through the court, or newspaper legal notices. Even if records were sealed at a later date, those records are sometimes made available after a certain number of years. In cases where there are still restrictions on access to adoption records and original birth certificates, be sure to consider other sources such as orphanage records, newspaper notices, or agency records which may not be subject to the same restrictions.

Conception Analysis

In addition to the records discussed above, conception analysis is important for establishing context. Full term pregnancies typically range between 247 and 284 days of duration from conception (ovulation) to delivery with 80 percent of pregnancies lasting between 256 and 280 days.[2] Based on this information and bearing in mind the background information recorded in non-identifying information from an adoption file (which sometimes includes duration of the adoptee’s gestation), conception dates can be estimated. Also, remember that an adoptee’s birthplace was not always the same as the place of conception.

2. Be open minded regarding the accuracy of background information

False Information

While it is important to get as much information as you can regarding the context of an adoption, you should also keep in mind that not all information may be correct. Information on original birth certificates may have been falsified. Details from non-identifying information files can be incorrect. Background provided by adoptive parents and others can also be incomplete or false. These differences are sometimes due to intentional efforts to mislead or conceal information on the part of a biological parent, adoptive parent, or other party involved in the adoption process such as cases where a bio-mother attempted to conceal her identity, an agency participated in unethical practices in arranging the adoption, or an adoptive parent is actively discouraging a search.

Inaccurate Information

However, differences between expectations and reality can also be due to simple misunderstandings, miscommunications, or lack of knowledge. Adoptive parents may not be fully aware of the circumstances of an adoptee’s birth or may have been told false information about the bio-parents. A biological mother may have misidentified the biological father and provided information about the incorrect individual in interviews with social workers. Even in these cases, if the information is not entirely correct, the background information is still helpful in providing some clues and may include a grain of truth.

Use “Known” Parents for Research

Sometimes background information can reveal the identity of one or both of an adoptee’s biological parents. In these cases, it is still beneficial to extend the ancestral lines of “known” parents using document evidence to ensure that their family tree aligns with the family trees of genetic cousins. In some cases, a named parent on an original birth certificate or the parent described in an adoption file may not be the biological parent, or information regarding the parent may have been falsified. Extension of the family trees of “known” parents helps researchers detect such scenarios.

3. DNA Test at multiple companies

DNA Test at multiple companies, including 23andMe, Ancestry, FamilyTreeDNA and MyHeritage

Autosomal DNA Testing

When attempting to solve a case of adoption, genetic genealogy testing can help. We recommend starting with autosomal DNA testing at each of the major DNA testing companies: 23andMe, Ancestry, FamilyTreeDNA, and MyHeritage (note that MyHeritage and FamilyTreeDNA accept transfers of raw data from other testing companies). Raw data might also be transferred to GEDmatch, Geneanet and other companies that accept transfers of data. Each company maintains separate databases of tested customers and it is never known where the closest and most important genetic cousins might have tested. Other types of DNA can also be helpful for adoption searches.

X-DNA Testing

X-DNA (which is tested as part of autosomal DNA tests) can sometimes help narrow the search for common ancestors between an adoptee and a genetic cousin. 23andMe, FamilyTreeDNA and GEDmatch all report on shared X-DNA between matches.

Y-DNA Testing

For male adoptees, or direct paternal descendants of male adoptees, Y-DNA can be helpful for identifying potential surnames or direct paternal origins for a biological father (Y-DNA is inherited along the direct paternal line – the same inheritance pattern as surnames in some countries). FamilyTreeDNA offers Y-DNA testing and 23andMe reports on broad Y-DNA haplogroup categories which can sometimes be used for evaluating relationship scenarios to close genetic cousins.

Mitochondrial DNA Testing

For male and female adoptees, or for direct maternal descendants of female adoptees, mitochondrial DNA testing can sometimes aid in learning about a biological mother or direct maternal origins. FamilyTreeDNA offers mitochondrial DNA testing and 23andMe reports on broad mtDNA haplogroup categories which can sometimes be used for evaluating relationship scenarios to close genetic cousins.

4. DNA Target test others

In addition to testing yourself or the adoptee, it might be beneficial to test others to aid in your genetic genealogy search. If a test taker is the adoptee themselves, then it can sometimes feel like there are no targeted testing options. However, adoptees might consider working with genetic cousins to target test their older relatives in order to pinpoint the nature of a relationship. For example, if an adoptee has a close genetic cousin who does not yet have any other tested close relatives, they might work together to target test aunts, uncles, parents, cousins, and other relatives of the genetic match to determine which branch of the match’s family tree is the source of share DNA with the adoptee.

Often through genetic genealogy analysis, adoptees can narrow a list of bio-parent candidates down to a handful of individuals. To further determine the identity of a bio-parent, it may be necessary to target test living descendants or other close living relatives of those individuals.

5. Try to distinguish paternal vs. maternal relatives

In adoption cases, genetic genealogy analysis can quickly become overwhelming because adoptees are often searching for two unknowns: a biological father and a biological mother. As a result, all genetic cousins are potentially pertinent to the search and if there are a large number of them, then the search can quickly become overwhelming.

Sorting DNA matches based on their relationships to each other is a great approach for any genetic genealogy case, but it is particularly important in adoption cases. At the most basic level, efforts should be made to try and distinguish relatives of one parent from relatives of another.

If an adoptees parents have different ethnic origins, ethnicity estimates can sometimes help in this process. Y-DNA, mtDNA, and X-DNA evidence can also aid in this effort. AncestryDNA recently began separating match lists into parent 1 and parent 2 categories.

Other companies which provide segment data regarding genetic cousins (23andme, FamilyTreeDNA, MyHeritage and GEDmatch) can also be used to identify genetic cousins who are sharing DNA in the same chromosomal regions but on different sides of a test taker’s family tree. Organizing genetic matches in this way can make the search more straightforward and feasible.

6. Collaborate with genetic cousins

As mentioned previously, in adoption searches, collaborating with close genetic cousins can be an important targeted testing opportunity. Even beyond these benefits, collaborating with genetic cousins can save time in researching and extending family trees for key genetic matches. They may be aware of bio-parent candidates in their extended family. They may be able to provide information to help extend their family tree enabling identification of common ancestors with shared matches and identification of ancestral candidates. Further, by building a relationship with these genetic cousins, you may be able to gain an ally in your search. Communication with bio-parent candidates from within their own family may be more successful than cold-call attempts from outside their family.

It can be nerve-wracking to contact close genetic cousins and bio-family. For more recommendations on establishing contact, see our blog post on how to contact your birth parent or sibling or this blog post on how to get responses from your DNA matches

7. Be patient with yourself, your matches, and others in your collaboration efforts

As important as it may be to establish contact with close genetic cousins and bio-family, these efforts can certainly be emotional and stressful. We recommend taking it slow so that you, your bio-family, and your genetic cousins have sufficient time to process new information that can be life-changing. Keep in mind that you may have had several months or even years to process knowledge of your adoption, while it may be the first time that some of the people you are contacting have heard or learned about your experience and existence. For you and for them, consider some of these resources for DNA surprises in a family tree.

If you don’t receive immediate responses from the individuals you have contacted, give them some time before following up. Don’t assume that no response is a rejection. Particularly for genetic cousins, they may not have received or seen your communication through the company messaging system. You may have attempted contact through an outdated address, phone number or email. They may not regularly check their social media accounts. Alternatively, they may just need time to process the new information and decide how they are going to move forward.

8. Use DNA and documents in adoption research to find the right people in the right place at the right time

Once common ancestors and relationships are identified for clusters of genetic cousins, then researchers can begin the process of searching for connections between ancestral candidates and finding individuals who were in the right place at the right time to be the source of shared DNA with DNA matches.

In adoption research, be sure to focus on the conception date and context rather than the birthdate and birthplace as the two are often different. In some adoption cases, it may be possible to narrow down a pool of candidates to a set of siblings on one side and a set of siblings on the other side. It may even be possible to narrow down further based on Y-DNA, mtDNA and X-DNA. Even so, there may still be several candidates.

If targeted testing and collaboration efforts are unfruitful or impossible, consider narrowing a pool of candidates down further by comparing what is known about a family against non-ID information or other background context. Also try narrowing a pool of candidates based on geographic proximity and life situation at the time of context. For some ideas on how to do this, review our blog on finding the right people at the right place at the right time. While it may not always be possible to prove the identity of a biological parent with DNA, it may be possible to use document evidence to identify the most likely candidate from a particular family.

9. Have a professional genealogist review your adoption research work

Searching for biological parents in an adoption research case can be a stressful and emotional journey in self-discovery. Contacting bio-relatives can be nerve-wracking. Results of contact with bio-family can be joyous or heart-breaking. Because of these considerations you will want to make sure that you are as confident as possible in your conclusions in a bio-parent search before contacting bio-parents, siblings, or other relatives.

Our project packages offer an excellent opportunity for a professional researcher to review previous work you may have performed and identify other scenarios you may not have considered. Even if you have arrived at a valid conclusion, you will want to make sure that your reasoning is written in a clear and well communicated manner to put newfound family members at ease in their questions and concerns. Our experienced and professional genealogists at Legacy Tree have found that bio-families of an adoptee are often extremely interested in reviewing our reports to better understand how they were identified as close biological family of a client. By working with a professional researcher, you can move forward in contact with confidence, and you can make sure that you have correct and proven answers in the important search to identify your biological parents.

For assistance with your adoption research, or to verify the information you have found, contact the experts at Legacy Tree Genealogists.

[1] Adoption Network, “U.S. Adoption Statistics,” https://adoptionnetwork.com/adoption-myths-facts/domestic-us-statistics/, accessed August 2021.

[2] A.M. Jucik et al, “Length of Human Pregnancy and contributors to its natural variation,” Human Reproduction (Oxford, England), 2013 Oct; 28(10): 2848–2855, http://www.ncbi.nlm.nih.gov, accessed December 2022.

oktober 17, 2022 by Paul - Legacy Tree Genealogists Researcher 8 Comments

Five Ways to Use the New DNA Coverage Estimator Tool at DNA Painter

The DNA Coverage Estimator is now available and makes the process of identifying matching ancestors through DNA much simpler than ever before.

In April 2018, Legacy Tree Genealogists published an article by Paul Woodbury introducing the concept of DNA coverage – the amount of an ancestor’s DNA represented in a DNA database through the test results of their tested descendants. Different descendants of an ancestor inherit different portions of that individual’s DNA. Therefore, they have different shared segments and total amounts of shared DNA with key genetic cousins. They may even have altogether unique key genetic cousins not shared with other descendants of the target ancestor. By testing multiple descendants of a research subject, it is possible to maximize the coverage of that individual’s DNA in a database.

As part of our previous article, we presented several equations to help in calculating and estimating the coverage of an ancestor. Coverage estimates can be helpful for prioritizing DNA testing candidates, developing strategies for collaboration with existing genetic cousins, and estimating amounts of DNA an ancestor might have shared with a key match or group of matches. However, using the published equations has often been cumbersome and complicated. Further the set up of the equations has limited the scalability for calculating coverage estimates for descendants of large families.

Recently, Leah Larkin at the DNA Geek refined and simplified the original equations to a more intuitive approach (See her description of the math here). Using these revised equations, Leah and Paul worked with Jonny Perl (owner and developer of DNA Painter) to create the coverage estimator tool. (To learn more about the tool and how to use it, visit Jonny’s article at DNA Painter).

This tool makes coverage analysis much more straightforward and accessible for genealogists -no more complicated calculations or limitations on the number of descendants to include. Here are just a few ideas of how you might use the coverage estimator tool in your research.

1. Estimate Your Ancestor’s Coverage in a Single Testing Database

One way you might use the coverage estimator tool is by entering all of the tested descendants of a known ancestor at a single DNA testing company (no mixing and matching between databases) in order to estimate their coverage at that company. If you have used WATO previously, you might use the same tree structure and mark the individuals who have tested.

For example, in the attached screenshot, I have identified the five tested descendants of Susan at AncestryDNA. Their combined DNA tests account for approximately 78.9% of Susan’s DNA at that company.

Keep in mind that while including all of the tested descendants of a research subject at a particular DNA testing company can give you an idea of what the coverage of that ancestor is in that particular database, the only way to take full advantage of that coverage is to collaborate with and seek access to the test results of the other tested descendants.

Without access to DNA test results for other descendants, you will still be limited to the coverage created by your own DNA test results. You won’t be able to learn about the additional chunks of DNA that other descendants inherited (and by extension the amounts of DNA shared with key genetic cousins) or even the additional key genetic cousins that you don’t match but they do.

2. Prioritize the Genetic Cousins with Whom You Should Collaborate

Because you can only fully leverage the coverage of your ancestor’s DNA by obtaining access to the test results of other descendants, another way you might use the coverage tool is to take the tree you created for your ancestor’s tested descendants and unmark all individuals for whom you do not currently have test result access keeping only those for whom you do have access. This will estimate how much of your ancestor’s DNA you have access to through tested descendants (we could call it your active coverage).

The DNA Painter tool will identify which individual should be the next tester to maximize your active coverage. (In this case, these individuals are already tested, but this information might be interpreted to help you understand who you should reach out to and seek to collaborate with). If possible, you should try to work with those individuals to obtain access to their test results and thereby benefit from the additional perspective, segments, matches, and relationships that their test results can provide for the purposes of your research.

The tool will also reveal how much more helpful these individuals could be for increasing your coverage. If you attempt to collaborate with the highest priority individual and they decline to share test result access, you can mark them as “unwilling to test” in the data, and the tool will let you know who is the next best priority for collaboration.

In the same example from above, I have access to the test results of Elizabeth, Peter and Bernard, but not Matthew or Lillian, so I unmarked Matthew and Lillian as having tested. This reveals that my active coverage (the coverage based on the test results I actually have access to) is about 68.8%. The tool then tells me that the next best person to test (or in this case, the best person for me to work with for collaboration) would be Lillian. Getting access to her test results would increase my active coverage by 7.8%.

3. Prioritize the Relatives You Should Invite to Test or Transfer

To this point we have only considered already-tested descendants of a research subject ancestor, but the Coverage Estimator tool can also help you identify priorities for targeted testing or autosomal DNA transfers.

Consider adding other known descendants of your research subject to your chart. These individuals might not have performed DNA testing yet. On the other hand, they may have performed DNA testing, but at a different database.

When you add these people into your tree, the tool will identify who you should contact to invite to perform DNA testing (or to upload their test results from elsewhere) in order to maximize coverage. As in the case of collaboration prioritization described above, if individuals decline to test or transfer, you can mark them as “unwilling to test” and the tool will identify the next best candidates.

Alternatively, if they indicate that they are willing (but they haven’t done it yet, or you will need to wait for the results to process) you can mark that they are willing to test, and the tool will update to identify the next best testing or transfer option for you to consider.

There will be a decreasing return on investment as you test more relatives. As potential increases in coverage become smaller and smaller with each new testing candidate that agrees to test or transfer (or who declines), you might want to consider if the potential increase in coverage is worth it for your case.

Keep in mind that 1% of an individual’s DNA represents about 70 centimorgans of DNA. Is 70 centimorgans more coverage worth the cost of a test? You decide.

In our example case, imagine that Susan had another son, John, who has two living sons. When we add them to the tree, the tool will identify them as the next best testing candidates to invite to test.

4. Estimate the Amount of DNA Your Ancestor Shared with a Genetic Cousin

Once you have started to collaborate with living descendants of a research subject and have obtained access to their test results, arranged transfers of their results into a desired database or arranged targeted testing, you can take coverage analysis a step further to being reconstructing the DNA of your research subject ancestor and estimating how much DNA they might have shared with key genetic cousins.

Consider a scenario where you and several other descendants of your research subject are all sharing DNA with a key genetic cousin who might be related through the ancestor of your subject. If you are working with results at a company that reports on segment data, you might generate a comparison between the key match and all independent tested descendants of your research subject. Next, you can determine the total number of centimorgans that match shares on unique segments with all of the descendants of the research subject. S

Some tools that might help with this include:

>DNA Painter’s Centimorgan Estimator tool (take the start position of one segment and the end position of a partially overlapping segment and calculate the length of the composite segment)

>DNA Painter’s Distinct Segment Generator (copy and paste two or more segments that multiple family members share with a single match and get the cM values for each composite segment and the total shared cM).

Once you know how much DNA a match shares with all of the tested descendants of the research subject, divide the total number by the coverage estimate as a decimal (e.g. 70.1% = .701) and you can estimate how much DNA your research subject might have shared with the genetic cousin. From there, you can evaluate the likely relationship levels using DNA Painter’s Shared cM Project tool.

Estimates are…Estimates

Keep in mind that the estimates provided by the Coverage Estimator are just that – ESTIMATES. The true coverage of an ancestor may be lower or higher given that genetic inheritance is random. As such, you should be careful in making assumptions and conclusions based off of this data.

As a general rule, the closer relatives a research subject has and the more tested descendants they have from unique descent lines, the closer the coverage estimate will be to the true coverage of the subject. At the very least (assuming there are not multiple relationships between the descendants of the subject and the key match), engaging in analysis of unique shared segments can reveal the minimum amount of DNA that an ancestor would have shared with a key genetic cousin.

In our example case, I was able to get the test results of Elizabeth, Peter and Bernie transferred to GEDmatch.com. I also managed to collaborate with a key genetic cousin, Katy, and invite that individual to transfer their test results to GEDmatch. While Elizabeth was born in the 1930s, and Peter and Bernie were born in the 1960s, Katy was born in the 1990s (and may be a generation further removed from the common ancestors with Susan’s descendants).

Comparisons of Katy’s DNA against Elizabeth, Peter and Bernie reveals that she shares 351 cM of DNA on unique segments with Susan’s tested descendants. Assuming that all of this shared DNA came from a common ancestor between Katy and Susan, we can conclude that Susan and Katy would have shared at least 351 cM of DNA with each other.

However, the combined results of Elizabeth, Peter and Bernie only account for a portion of Susan’s DNA – about 68.8% of her DNA according to the Coverage Estimator tool. If we assume that the 351 cM of DNA that Katy shares with Susan’s descendants represents only 68.8% of the DNA she would have shared with Susan, we estimate that Katy might have shared approximately 510 cM.

With that level of sharing, we would expect that Katy is related to Susan at the level of a first cousin once removed or (given her age) possibly at the genetically equivalent level of a great-grandniece. For more information on navigating genetically equivalent relationships see our article on the subject.

The amounts of DNA that Katy shares with Elizabeth, Peter and Bernie separately corroborates this hypothesis, but the combined unique segments and application of coverage estimates provides stronger evidence of the proposed relationship at higher probabilities than any of the amounts of shared DNA between Katy and Elizabeth, Katy and Peter or Katy and Bernie.

5. Estimate the Amount of DNA Your Ancestor Shared with a Deceased Relative

In the case above, we considered a scenario where a group of descendants of a research subject were compared against a single genetic match. To take it one step further, you might also consider the unique shared segments between two groups of matches. You could calculate the coverage of the descendants of the research subject for whom you have test result access, and then in a new chart, calculate the estimated coverage of a candidate relative based on the relationships between the tested descendants of the candidate.

Use the same tools as were utilized in the previous recommendation (DNA Painter’s Centimorgan Estimator, and Distinct Segment Generator) to determine the segments that the research subject’s descendants share with the candidate relative’s descendants. Alternatively, you can get all individuals transferred to GEDmatch and use the Lazarus tool to identify the segments shared between both groups.

Next, divide by the coverage of the research subject (in decimal format) and divide again by the coverage of the relative candidate (in decimal format). In this way you can estimate how much DNA the research subject and the relative candidate would have shared in common with each other.

In our sample case, after transferring the test results of Elizabeth, Peter and Bernie to GEDmatch, we found a group of additional genetic cousins already at GEDmatch including a pair of siblings and their aunt (coverage of 68.8% for the common ancestor). All three matches descended from a woman named Laverna. Using the Lazarus tool with Elizabeth, Peter and Bernie in one group and these three matches in the other group, we found that Susan’s descendants shared 472.2 cM of DNA with the three descendants of Laverna. When we divided this by .688 (for Susan’s coverage) and by .688 (for Laverna’s coverage) we found that Susan and Laverna might have shared approximately 999 cM of DNA (100% probability of a first cousin or genetically equivalent relationship). Additional exploration revealed that Laverna was a great-niece of Susan (which is genetically equivalent to a first cousin relationship).

Again, keep in mind that these are estimates, the closer the descendants of each individual, the more independent descendants who have tested, and the higher the estimated coverage, the more accurate the estimates of how much DNA a research subject may have shared with a match or with another relative candidate.

Give it a try, use the Coverage Estimator tool to estimate the coverage of an ancestor’s DNA in any given testing database, to prioritize the individuals with whom you will collaborate, seek access to test results, invite to transfer or invite to test, and ultimately to help determine the amount of DNA your ancestor shared with a deceased relative.

If you have a tough DNA mystery you’d like to solve, our DNA experts can help! Contact us today for a free consultation to discuss which of our project options works best for you.

juni 15, 2022 by Paul - Legacy Tree Genealogists Researcher Leave a Comment

Introduction to Ethnicity Admixture

Paul Woodbury is a DNA team lead and professional researcher at Legacy Tree Genealogists where he has helped to solve hundreds of genetic genealogy cases. In this article, a reprint from an issue of NGS Magazine, Paul discusses how genetic ethnicity estimates can provide valuable clues for the composition of a test taker’s family tree. This article is published with permission.

Ethnicity is a grouping of people based on shared attributes like traditions, ancestry, language, culture, history, or religion.

Obtaining autosomal ethnicity admixture results is the primary reason many people perform DNA testing. The DNA testing companies recognize this interest and in recent years have made genetic ethnicity admixture estimates the focus of their marketing efforts.

In fact, autosomal DNA test results from the major companies include at least two elements: ethnicity admixture estimates and genetic cousin match lists. While the match lists are typically the most useful elements for genealogical research, ethnicity admixture estimates can provide significant context and clues regarding a test taker’s family tree.

What is ethnicity?

An ethnicity is a grouping of people who identify with each other based on shared attributes that distinguish them from other groups, such as traditions, ancestry, language, culture, history, or religion. Individuals of the same ethnicity often belong to the same population (all humans living in a geographic area), and in turn, may share a similar gene pool.

First, it is worth noting that test takers inherit DNA from people rather than places. While some are accustomed to describing their ethnicity admixture in terms of where their DNA came from, people actually inherit DNA from ancestors who lived in populations residing in specific locations rather than from the place where their ancestors lived.

This is an important distinction due to the long history of human migration. While an individual’s more recent ancestors may have lived in the same location for hundreds of years, earlier generations may have come from different and perhaps geographically distant populations—which might result in surprising ethnicity estimates based on genetic information.

Map of France showing Brittany, Alsace, and the Basque country, areas with distinct linguistic and cultural histories underscored by genetic differences in France as a whole. Modern boundaries do not always align with the boundaries of historic populations. Eric Gaba, “France location map-Departements-2015,” Wikimedia Commons (https://commons.wikimedia.org), CC Attribution-Share Alike 4.0 International license; labels added by author.

Ancestors of a test subject were members of the wider populations in which they lived. Some populations have been isolated from surrounding populations for hundreds to thousands of years due to language, geography, religion, or other factors.

When a population is isolated, the mutations and unique genetic markers generated and commonly held within the population differentiate it genetically from other populations. Other populations have had frequent interaction, migration, and gene flow with surrounding populations, making it difficult to determine which DNA corresponds to historical populations.

While genetic ethnicity estimates would ideally rely on historical DNA samples of individuals who were members of a population, limitations on historical DNA samples require inference of ethnicity based on current populations. However, the boundaries of modern states do not always align well with historically distinct populations.

For example, what is “French” DNA? Is it the DNA of the population of Brittany, which has strong historical connections to the Celtic populations of the British Isles? Is French DNA the DNA of the population of Alsace and Lorraine in eastern France, which has switched between French and German jurisdictions several times over the last several hundred years? Is French DNA the DNA of the Basques on the southern French border, who have been isolated by language and geography for thousands of years? Is French DNA the DNA of people who have lived for generations in and around Paris?

To answer such questions and provide ethnicity estimates, each genetic genealogy testing company relies on some basic principles.

How it works

While each company uses different approaches to provide ethnicity estimates, these methods share some of the same elements: curation of reference panels, the definition of populations, and probability assignment.

Principal Component Analysis is a process that reduces dimensionality. In the curation of reference panels, it is used as a quality control measure to isolate the unique genetic profiles associated with specific populations. Scotted400, “Principal Component Analysis of European Populations from the Genome Ukraine Project,” Wikimedia Commons (https://commons.wikimedia.org), CC BY 4.0 license. Ukrainian individuals are circled and colors reflect prior population assignments from European samples.

In order to determine ethnicity admixture and estimate the populations to which a test taker’s ancestors belonged in the past, the companies first identify individuals whose ancestors all lived in the same region. The companies use extant public databases as well as samples from their own databases to curate a reference panel of samples for individuals whose ancestry is from a single population.

In this effort, they seek unrelated individuals who do not share large segments or chunks of DNA with each other due to recent common ancestry. They also apply quality control measures such as principal component analysis (PCA) to remove outliers: individuals whose genetic ancestry does not coincide with their reported genealogical ancestry or whose genetic profiles are extremely dissimilar to other individuals from the same tested population. Through this process, DNA testing companies can identify markers of DNA that are only found or are predominantly found, in a single population or in a handful of closely associated populations.

Based on sampling methods, residences of test takers and their ancestors, and genetic similarity between the samples in a population, the companies define regions or populations with unique and distinct genetic profiles.

Each company defines populations and regions differently. At AncestryDNA, Danish admixture is sometimes split between Norway, Sweden, and Germanic Europe regions, while at Family Tree DNA, Denmark is included in both the Scandinavia and Central Europe designations.

Because companies use different reference panels, they define these regions differently, too. For example, an individual with several generations of ancestry in Denmark may be assigned Scandinavian ancestry by one company, Norwegian and Swedish ancestry by another company, and Germanic ancestry by another company, due to the ways regional boundaries are drawn and defined by the different companies.

While each company is typically able to distinguish between drastically different and geographically distant populations, some may not be able to distinguish as well between geographically adjacent or historically linked populations.

Currently, AncestryDNA’s reference panel has 45,000 samples, 23andMe has 14,000, and MyHeritage has 5,000.[1] Other companies have not reported the size of their reference panels, but they are probably smaller.[2] As more people from a population are tested and included in a reference panel, a more fine-tuned definition of populations becomes possible. Therefore, it is likely that as companies expand their reference panels to include more samples from individual populations, their ethnicity estimates will continually be refined into smaller populations.

“DNA Story for Private,” Ethnicity Estimate, updated, private database, Ancestry (https://ancestry.com)
“myOrigins,” ethnic makeup percentage for kit private, private database, FamilyTreeDNA (https://familytreedna.com)

Once a company has assembled a reference panel, it applies different algorithms and approaches to analyze a test taker’s data. Each testing company tests several hundred thousand markers of DNA across a tester’s genome called single nucleotide polymorphisms (SNPs), which are hotspots for genetic variability in human populations. Testing companies analyze a portion of these SNPs as part of ethnicity admixture estimation and consider the prevalence of particular SNPs in specific populations.

Ancestry and 23andMe chop a test taker’s DNA results into smaller chunks or windows of consecutive markers, compare each window to the reference panel and assign the chunk to the population in which its genetic profile is most likely to occur. These chunks and their corresponding assignments are then used to provide percentage estimates of ethnicity regions.

Genetic Communities, Recent Ancestor Locations, and Genetic Groups

Each testing company’s ethnicity estimates report percentages of DNA assigned to populations or regions where a test taker’s ancestors may have lived within the last thousand years. In addition, AncestryDNA, 23andMe, and MyHeritage have started supplementing these estimates with reports of locations and countries where a test taker’s ancestors may have lived more recently and migration patterns in which ancestors may have participated in the last few hundred years.

While broad ethnicity admixture estimates provide high-level context for an individual’s ancestry, these communities, groups, and locations can provide specific clues and hints for follow-up in a genealogical investigation.

Ethnicity estimates consider the prevalence of specific SNP markers in a population and assign percentages of ethnicity, based on similarity to a reference panel. The estimates might be anomalous or unrepresentative of expected ethnicity regions due to historical migrations or population characteristics.

Particular communities, locations, and groups are assigned based on networks of individuals who share large chunks of DNA from recent common ancestors as well as recent ancestral locations, communities, or migration patterns. These communities, locations, and groups are often much more accurate and representative of recent ancestral heritage, although percentages are not assigned to them.

A test taker’s assignment to an unexpected community, location, or group could be due to recent misattributed ancestry or a migration pattern associated with a particular area. A tester from Denmark may have connections to descendants of Danish immigrants to the United States, or a tester from Ghana may find connections to communities of descendants of enslaved communities in the Caribbean.

Why the differences?

Some individuals who test at multiple DNA testing companies receive different ethnicity estimates from them. These differences and changes are not a reflection of the validity of the underlying science, but rather the differences between the reference populations, algorithms, and approaches used by each of the companies.

Even if users test at a single company, it is likely that over the course of several years they will receive updates to their ethnicity admixture estimates. These updates inevitably cause some to complain of their “lost” ethnicities or decreases in their percentages.

Conclusion

In the end, ethnicity estimates are still estimates. As reference panels grow larger, and as companies refine their methods and algorithms for estimation, ethnicity estimates will continue to become more accurate and representative. Even so, ethnicity estimates as they currently stand can provide valuable context and clues for the structure and composition of a test taker’s family tree.

Legacy Tree Genealogists has been at the forefront of genetic genealogy research services for almost two decades. Our team of experts has solved DNA-related cases and can help you solve your family DNA puzzles! Contact us today for a free quote.

Sources

Catherine A. Ball, et al., “Ethnicity Estimate 2020 White Paper,” Ancestry (https://www.ancestrycdn.com/dna/static/pdf/whitepapers/Ethnicity2020_ white_paperV2.pdf). Eric Y. Durand, et al., “A scalable pipeline for local ancestry inference using tens of thousands of reference haplotypes,” updated 7 December 2020, 23andMe (https://permalinks.23andme.com/pdf/23-16_ancestry_composition.pdf). Esther, “Introducing our New DNA Ethnicity Analysis,” MyHeritage, 1 June 2017 (https://blog.myheritage.com/2017/06/introducing-our-new-dna-ethnicity-analysis).
Jayne Ekins, “DNA Ethnicity Estimation: Reference Panels,” Your DNA Guide (https://www.yourdnaguide.com/ydgblog/2019/6/6/dna-ethnicity-estimation-reference-panels).

maj 16, 2022 by Paul - Legacy Tree Genealogists Researcher 3 Comments

Eight Steps to Pursue with New Autosomal DNA Test Results

Paul Woodbury is a DNA team lead and professional researcher at Legacy Tree Genealogists where he has helped to solve hundreds of genetic genealogy cases. In this article, a reprint from an issue of NGS Magazine, Paul discusses steps a researcher could take to begin using DNA test results. This article is published with permission.

Several weeks after the submission of a DNA sample, the results finally arrive! An email appears announcing that the test has completed processing. It includes a link to sign in to review the test results. But what comes next? Where to start? The following are my recommendations for the first steps a researcher might take to begin using test results. This article provides a brief overview, and future columns will dig deeper into each of these topics.

Ethnicity estimates often identify the regions where a test taker’s ancestors lived in the last thousand years and more specific genetic communities associated with the ancestors in recent centuries. Courtesy of Ancestry.

Set up a profile and attach a family tree

First, if a profile has not been created, set one up. When considering what to include, review my previous article on this topic. [1]

Adding a profile image, answering questions regarding research interests, listing ancestral surnames, and attaching a family tree to the account can make DNA test results more useful. These items also help make test takers more approachable from the perspective of their newfound genetic cousins.

Review ethnicity admixture reports

Ethnicity admixture is one of the major reasons that people initially pursue DNA testing. Each of the testing companies invests attention, advertising, and marketing for this element. While these reports are typically not very helpful for genealogical research questions, they do provide a broad context for other genetic genealogy pursuits. They also provide a good introduction to DNA test results.

Often these results include ethnicity admixture regions indicating the broad geographic areas where a test taker’s ancestors may have lived within the last thousand years as well as more specific genetic communities or ancestral populations that may have been associated with the ancestors in recent centuries.

When evaluating ethnicity admixture reports, researchers might ask these questions:

▪ Does the test taker have significantly more than 50 percent admixture from a particular region? If so, both parents may have ancestry from that region since individuals inherit only 50 percent of their autosomal DNA from each parent.

▪ Does the test taker have an even split between two main ethnic regions? If so, one parent may be from one area and the other parent from the other.

▪ Given the documented family tree of the test taker, do the ethnicity results generally align with expectations? Keep in mind that some populations were historically admixed, so it is possible that admixture from an expected region has been assigned to a neighboring region or otherwise associated region.

▪ Are any admixture regions or results anomalous, given the context of the test taker’s family tree? Anomalous in this context means admixture that is 10 percent higher or lower than would be expected from particular regions and their neighbors.

▪ Do any genetic communities or more specific highlighted ancestral regions fit with what is known regarding the individual’s family tree?

If surprises occur in a test taker’s results, I recommend exploring the anomalies further before jumping to a hasty conclusion. Consider whether unexpected admixture regions might be associated with a known branch of the test taker’s family tree. Explore how the testing company organizes and categorizes specific regions and what ethnic admixture might be expected for individuals from those regions. If an aspect of test results still does not make sense, consider shared matches.

This chart demonstrates that close relationships have clearly defined ranges of amounts of shared DNA, while more distant relationships have more overlap in amounts of shared DNA. Blaine Bettinger, “The Shared cM Project – Version 4.0,” The Genetic Genealogist blog, https://thegeneticgenealogist.com. CC 4.0 Attribution License.

Review the closest genetic cousins

Perhaps the most genealogically useful part of a user’s DNA test results is the list of genetic cousins. Each company presents a list of individuals who are likely related to the test taker based on shared DNA. Shared DNA is measured in centimorgans (cMs), a measure of the likelihood of recombination as well as the number of segments individuals share with each other. The more total centimorgans a test taker and a genetic cousin share, the more likely that they share recent common ancestors.

Some ranges of shared cMs are much more likely for particular relationship levels than they are for others. For example, the amounts of DNA shared between siblings are much larger than the amounts of DNA shared between first cousins. However, with more distant relationships, distinguishing between relationship levels can be more difficult. A third cousin could share as much DNA with a test subject as a fourth cousin, and a fifth cousin could share as much DNA as an eighth cousin.

Each testing company organizes DNA match lists by default based on amounts of shared DNA, with the closest likely relatives listed first. The closest matches in a test taker’s list of genetic cousins are those for whom it is most likely possible to determine the nature of a relationship. Clicking through to view their profiles may give insight into their family trees.

When reviewing the match list of a test taker, researchers might consider these questions:

▪ Have any close relatives of the test taker performed DNA testing? Do they appear in the match list as would be expected?

▪ Do any known relatives share amounts of DNA consistent with their proposed relationships? Keep in mind that half-relatives share half the amount of DNA that would be expected for a full relationship. To evaluate amounts of shared DNA, review the Shared cM Project Calculator at DNA Painter. [2]

▪ Are there any close genetic cousins (sharing more than 200 cM) who are unknown? Do they have family trees that help reveal their likely relationship?

If close tested relatives do not appear in a match list or share less DNA than would be expected, or if unknown close matches appear, consider the possibility of misattributed parentage for either the test subject or the relative. Follow the next steps to aid in determining how they might be related.

Consider shared matches

Interpretation of autosomal DNA test results is established on the principle that when two individuals share DNA with each other, they share a common ancestor. When those two individuals also share matches in common, those shared (or in-common-with) matches are often related through the same ancestral lines.

Analysis of these clusters of shared matches can help researchers categorize groups of matches with specific lines of ancestry and quickly determine how an unknown relative might be related to a test taker.

Identification of these groups can also aid in organizing and filtering a match list to isolate genetic cousins who may be related through a line of interest and whose relationships, in turn, may be pertinent to answering a genealogical research question. This approach for considering shared matches is most effective in non-endogamous populations, where it is most likely that individuals share only a single relationship. [3]

Microsoft Office products include a SmartArt feature in a hierarchy format which researchers can utilize to create relationship charts between genetic cousins.

Contact genetic cousins

Once a researcher has determined the likely relationship for an unknown relative or at least determined through which branch of a test subject’s family they are likely related to, it can be beneficial to contact that person to request additional information regarding his or her family tree. When a genetic cousin’s relationship is difficult to determine, collaboration between two individuals can help in the successful determination of the connection.

Each DNA testing company offers avenues for contact with genetic cousins which can aid in establishing relationships of collaboration and cooperation to solve genealogical problems. Even for those genetic cousins whose relationship is known, it may be helpful to establish contact to learn about records, photographs, stories, and information passed down to them through their family or obtained through another person’s family history research efforts.

Take notes

Each testing company offers an interface for annotating important information about genetic cousins. Researchers might record the exact relationship to an individual once it is determined when they attempted contact with the genetic cousin, the maiden name of someone using her married name, or the full name of someone using a vague username. They might even note the relationship path between the test taker and the match to aid in future interpretation.

Even if researchers choose not to record notes in the company interface, they should organize their analysis of relationships using their own note-taking system. They might also create charts to visualize relationships between genetic cousins such as the Smart Art chart shown here.

Exploration of shared matches to genetic cousins can help in the organization of matches into clusters of related individuals. Research can then focus on groups of matches most likely pertinent to a research question. Shutterstock license.

Search and filter

Each company offers several sets of search functions and filters to aid in organizing and interpreting match lists. Users can search for surnames reported in family trees, usernames, or ancestral surname lists. They might search for locations where their ancestors lived. They might filter the list based on shared DNA, shared ethnicity admixture regions, when an individual appeared as a match, or where a match currently lives.

Exploring these filters can help identify more distant matches who may be related through particular ancestral lines or may share surnames or localities of interest in their family trees.

Explore other company tools

Besides the research avenues listed above, each company offers additional features and tools to aid in the analysis and interpretation of DNA test results. 23andMe offers reports on Y-DNA and mtDNA haplogroups, which might suggest further insights, and reports on physical traits and health information, depending on the test purchased.

Ancestry offers a dot-labeling feature for organizing matches into groups. Its ThruLines seek to identify all genetic cousins in a list showing descent from the reported ancestors of the test subject.

MyHeritage offers an AutoCluster tool to help identify clusters of genetic cousins. Its Theories of Family Relativity generate hypotheses of potential relationship paths between a test taker and genetic cousins.

FamilyTreeDNA, 23andMe, and MyHeritage all offer chromosome browsers to aid researchers in determining and analyzing exactly which segments of DNA are shared between test takers and their matches.

Conclusion

These are some of the first steps a researcher might take when exploring newly processed autosomal DNA test results. In future articles, I will describe each step in more detail and explore other options for using DNA test results to solve genealogical problems.

Getting a DNA test is a great way to start your genealogy journey; however, completing that journey requires hard work and access to the latest tools and services. If you’ve taken a test and need assistance analyzing the results, or if you have a genealogy question you think DNA might be able to answer, we would love to help! Contact us today for a free quote!

References

Paul Woodbury, “Foundations for Genetic Genealogy Success: Profiles and Family Trees,” NGS Magazine, October-December 2020, 61.
Jonny Perl, “The Shared cM Project 4.0 tool v4,” DNA Painter (https://dnapainter.com/tools/sharedcmv4, accessed 11 February 2021).
Endogamous populations have been isolated historically due to geography, language, or religion, resulting in multiple shared ancestors or descent from the same ancestors multiple times. Consequently, a large number of genetic cousins share DNA with many other members of the endogamous population, perhaps through independent relationships.

april 18, 2022 by Paul - Legacy Tree Genealogists Researcher 2 Comments

Where to Test? Genetic Genealogy Testing Options

Paul Woodbury is a DNA team lead and professional researcher at Legacy Tree Genealogists where he has helped to solve hundreds of genetic genealogy cases. In this article, a reprint from an issue of NGS Magazine, Paul discusses four major DNA testing companies’ tools and their benefits. The article is published here with permission.

Four major DNA testing companies offer genetic genealogy testing—23andMe, AncestryDNA, FamilyTreeDNA, and MyHeritage— and there are several smaller testing companies. Each company has unique benefits, advantages, and insights to offer the serious genealogist.

This article reviews (in alphabetical order) each of the major companies and some of the features they offer as of late 2020. For more detailed and continually updated comparisons of testing companies, read the International Society of Genetic Genealogy’s “Autosomal DNA Testing Comparison Chart.”*

23andMe

23andMe provides a $99 autosomal DNA test dedicated to ancestry analysis and a health + ancestry test for $199. Though the main focus of the ancestry test is autosomal DNA, 23andMe tests also include data regarding the X-chromosome, Y-DNA, and mitochondrial DNA haplogroups. More detailed analysis of the underlying data is possible through the browse raw data and download raw data functions.

The 23andMe ethnicity chromosome painting shows not only ethnicity admixture percentages, but also which segments of DNA originated from particular populations. © 23andMe, Inc. 2020. All rights reserved and distributed pursuant to a limited license from 23andMe.

With twelve million customers, 23andMe maintains the second largest database of tested users. The company sells kits in fifty-six countries leading to decent representation from international populations. Connecting with users who have tested at 23andMe is possible by opting into the DNA Relatives features of the database. In establishing a profile, users have significant control over the information that is available to matches.

Ethnicity estimates at 23andMe are widely regarded as among the most useful for genealogical research given their general accuracy and the company’s ethnicity chromosome painting which enables the formulation of hypotheses of relationship. For example, if two large segments of DNA in the same overlapping region on both of an individual’s chromosomes are assigned the same ethnicity admixture, it is likely that both parents have ancestry from that region. Alternatively, if a particular ethnicity is only found in long segments on a single copy of each chromosome pair, it is likely that only one parent has admixture from that particular region.

Ethnicity assignments on the X-chromosome or X-chromosomes can help in understanding which lines may be the source of DNA from unique ethnic regions. Recent updates have aided in tying ethnicity estimates to specific countries, regions, and communities. The company permits users to download segment data associated with ethnicity estimates.

The 23andMe match list is currently capped at fifteen hundred matches. For more matches, it is necessary to purchase an upgrade. Filters for the match list enable users to search for individuals not only by username, surname, ancestral surname, or ancestral location, but also by haplogroup, though some filters are currently only available in the upgraded version. Other unique features of the 23andMe interface include its Family Tree view of a match list which incorporates amounts of shared DNA and haplogroup data to estimate how matches might fit into a larger family tree, thus offering a head start on hypothesized relationships.

23andMe’s Family Tree view of the match list considers amounts of shared DNA between a test subject and matches, amounts of shared DNA between matches, and haplogroup data to estimate the nature of genetic relationships and the structure of a test taker’s family tree relationships with close matches. © 23andMe, Inc. 2020. All rights reserved and distributed pursuant to a limited license from 23andMe.

One of the strengths of the 23andMe platform is the ability to determine which genetic cousins are shared in common with a test subject and the amounts of DNA they share with each other. Another advantage is the ability to perform direct shared segment comparisons between individuals who are sharing genomes with a test subject or who are participating in open sharing.

In terms of segment analysis, 23andMe is the only testing company to report the presence of fully identical regions shared between two individuals, which assists in the evaluation of sibling relationships. These features of chromosome comparisons make 23andMe particularly helpful when working with the test results of individuals belonging to endogamous populations.

AncestryDNA

The $99 AncestryDNA test is an autosomal test dedicated to ancestry analysis. An AncestryHealth test which includes all ethnicity and matching features is available as an upgrade from the AncestryDNA test or as a separate kit option. While the test includes markers from the X-chromosome, Y-chromosome, and mtDNA, only autosomal DNA is utilized in the creation of reports. Raw data is downloadable from Ancestry, but match list data is not.

With more than eighteen million customers, AncestryDNA has the largest database of tested users. AncestryDNA kits are sold in thirty-four countries including the United States, Canada, Australia, and much of Europe. Currently, its strongest markets are in English-speaking countries.

Connecting with other users who have tested is possible through Ancestry’s messaging system and inclusion in match lists. Unlike other companies, AncestryDNA does not share information regarding the exact underlying segments of DNA shared between a test taker and matches—a feature that some consider an advantage given the medical, physical, and other traits that can sometimes be inferred based on shared segment data.

AncestryDNA provides tools for organization and clustering with colored dot labels. This example shows how one researcher used dots to assign genetic cousins to particular branches of his family tree. Courtesy of Ancestry.

AncestryDNA offers easy and straightforward means of sharing match list information with collaborators working on the same research problems. Descendants of a research subject inherit different portions of that individual’s DNA, so obtaining access to the test results of multiple descendants can help in achieving a clearer picture of relationship patterns.

AncestryDNA’s ethnicity estimates are helpful for genealogists given their continuous development and improvement in accuracy. In particular, the Genetic Communities feature is helpful for identifying recent migrations and groups with which an individual’s ancestors may have been associated.

Match lists at AncestryDNA are limited to those sharing more than 8 centimorgans of DNA with a test subject. Sophisticated matching algorithms help to prioritize the most pertinent matches based on shared DNA and cutting out shared DNA on unreliable segments or in pile-up regions. Recently, as part of the match list experience, AncestryDNA also has provided information on pre-algorithm total shared DNA, longest segments, and probabilities of relationship based on shared DNA.

AncestryDNA includes features for sorting, labeling, clustering, and otherwise organizing DNA matches using colored dots. Using these labels, it is possible to organize matches based on their relationships to each other into clusters of related individuals. Once organized, these groups can be further explored to identify common ancestors, surnames, locations, or populations connecting the members of a group.

Family trees attached to the test results of AncestryDNA customers fuel the creation of ThruLines reports, which show the connections between genetic cousins and a test subject even when those genetic cousins have limited family trees. Courtesy of Ancestry.

Because AncestryDNA is part of the Ancestry company, the integration of records, family trees, and matching technologies greatly enhances the AncestryDNA experience. When users attach family trees to their test results, these trees generate shared ancestor hints and shared surname and location hints. The ThruLines feature enables discovery of relationship hypotheses based on family trees of genetic cousins regardless of the size of those trees. Even if a match’s family tree is limited, Ancestry can use data from its large collection of user-submitted trees to extend ancestral lines to identify possible connections and hints for review.

FamilyTreeDNA

FamilyTreeDNA is the only genetic genealogy testing company to offer Y-DNA tests and mitochondrial DNA tests that are genealogically conclusive; it also offers tools for interpretation and evaluation of Y-DNA and mtDNA evidence. Its most advanced Y-DNA test, Big-Y, enables customers to participate in ongoing research and refinement of the human Y-chromosome phylogenetic tree. Besides Y-DNA and mtDNA tests, the company offers a $79 Family Finder autosomal DNA test. While it has not entered the health testing market, FamilyTreeDNA has opened up to collaboration with various law enforcement agencies. Though this development has raised concerns for some, others deem this development an advantage and a benefit.

FamilyTreeDNA is the only company that offers genealogically useful Y-DNA and mitochondrial DNA tests in addition to autosomal DNA offerings. Courtesy of FamilyTreeDNA.

Although FamilyTreeDNA maintains a smaller database of autosomal DNA test results (just over one million customers), the fact that its test is sold in most countries and territories results in a more international customer base. The ability to transfer test results to FamilyTreeDNA from other testing companies provides an easy and cost-effective way of exploring another testing pool or taking advantage of segment analysis tools not available elsewhere. While other companies limit communication with matches to in-house systems, FamilyTreeDNA enables connection between researchers through direct contact information.

Recent updates to FamilyTreeDNA ethnicity admixture reports have improved the estimates. In contrast to other companies that report shared ethnicities between matches as part of the match list, FamilyTreeDNA includes this information in its ethnicity report.

In addition to filters and sorting mechanisms available at some other companies, the FamilyTreeDNA matchlist enables sorting by largest segment, matches shared in common with a subject and a match, and matches not shared in common with a subject and a match. Filtering by largest segment can be helpful when working with test results for individuals in endogamous populations. Filtering match lists by individuals shared in common or not in common with a particular match can be helpful for quickly identifying other individuals likely related through the same ancestral line as the match as well as ancestral lines other than the line on which the match is related.

FamilyTreeDNA’s chromosome browser offers the opportunity to compare segment data (including X-DNA) and permits application of different centimorgan thresholds. This application is useful for cutting out the small segments FamilyTreeDNA includes in the calculations of total shared DNA and for raising thresholds to higher levels for evaluation of pertinent matches in endogamous populations. The chromosome browser also enables downloads of all segment data shared with genetic cousins which can be analyzed in spreadsheets.

FamilyTreeDNA provides platforms for collaborative projects with surname, geographic, haplogroup, and other focuses. For example, the Mayflower project managed by the General Society of Mayflower Descendants is dedicated to identifying the Y-DNA and mtDNA haplotypes of Mayflower passengers and their direct line descendants. Courtesy of FamilyTreeDNA.

FamilyTreeDNA offers platforms for collaborative group projects run by volunteer administrators. The subjects of these collaborative projects include surname studies, geographic localities, haplogroups, and descendants of particular individuals.

MyHeritage

The $79 MyHeritage DNA test is an autosomal DNA test. The platform tests markers on the Y-chromosome, X-chromosome, and mtDNA, but these details are not included in customer reports. As with other companies, MyHeritage permits downloads of raw data and match data.

The MyHeritage chromosome browser tool enables true triangulation analysis: identification of segments of DNA shared between a test subject and at least two other DNA matches. Courtesy of MyHeritage.

While MyHeritage is a relative newcomer to the genetic genealogy testing scene, it has experienced remarkable growth. As of late 2020, more than four million customers had tested in their database. Since MyHeritage markets and ships worldwide, the company often holds the best matching results for individuals outside English-speaking countries. Like FamilyTreeDNA, MyHeritage accepts transfers of autosomal DNA data from other testing companies, offering an easy and cost-effective means of exploring another testing pool or taking advantage of additional analysis tools.

Connecting with other users at MyHeritage is possible through its integrated messaging system. The company does not offer the option to share access to test results, but its transfer system permits management of multiple kits under a single account. In this way, MyHeritage enables exploration of research questions from the unique perspectives provided by different descendants of a research subject.

The MyHeritage Auto Cluster, provided to users through collaboration with Jan-Evert Bloom of Genetic Affairs, is an excellent resource for quickly grouping genetic cousins into meaningful groups for meaningful analysis of shared ancestors, surnames, locations, and populations. Courtesy of MyHeritage.

Since MyHeritage offers access to documentary research collections and offers tools for tree-building, its database has a relatively high percentage of tested customers with attached family trees to aid in interpretation of relationships. Ethnicity estimates at MyHeritage are in a process of continual refinement and include some categories not found elsewhere, including differentiation between unique Jewish populations.

MyHeritage match lists offer a range of analytical tools, filters, searches, and sorting options. When users connect their test results to family trees, it is possible to generate Theories of Family Relativity, SmartTree Matches, and lists of shared surnames and locations. Theory of Family Relativity analyzes the family trees of a subject and the family trees of matches and identifies possible connections between them through the assistance of other trees and record collections. MyHeritage not only reports which genetic cousins are shared matches but also identifies how much DNA those individuals share with each other. This feature is particularly helpful for prioritization of matches in endogamous populations.

The MyHeritage chromosome browser tool enables identification of truly triangulated segments (segments of DNA that a test subject and at least two matches share with each other). MyHeritage has also partnered with developer Evert-Jan Bloom of Genetic Affairs to provide cluster reports for users through the AutoCluster feature. Relationships between genetic cousins are identified as colored squares in a matrix and are grouped with other individuals who share the same matches. Clusters are often composed of individuals who descend from the same ancestral couple or who have ties to the same community or population. Analysis of clusters can assist in identifying which genetic cousins are related through which family lines and which might be pertinent to a research question.

Where to test? Everywhere!

Due to the unique features, tools, and insights that test-takers can obtain at various companies as well as the different genetic cousins with whom they might connect in the separate testing pools, there is a benefit to testing at any and all of the major DNA testing companies.

This article summarizes the nuts and bolts of pricing, testing types, database size, international reach, collaboration opportunities, ethnicity estimates, match list features, and analysis tools. Other considerations that might guide testing choices include privacy options, involvement with third parties (health, pharmaceutical, and law enforcement), and sampling methods.

As the major testing companies and perhaps other companies continue to develop and grow in the future, it is likely that additional considerations will affect prioritization of which company or companies to utilize for genetic genealogy research. For now, the unique advantages of the major companies merit consideration of testing at each or at least testing and transferring into all four databases.

Getting a DNA test is a great way to start your genealogy journey; however, completing that journey requires hard work and access to the latest tools and services. If you need some assistance, our genealogists will work with you to discover your family history. Contact us today for a free quote!

*“Autosomal DNA Testing Comparison Chart,” International Society of Genetic Genealogy Wiki (https://isogg.org/wiki/Autosomal_DNA_testing_comparison_chart : accessed October 2020).

juli 7, 2021 by Paul - Legacy Tree Genealogists Researcher Leave a Comment

Foundations for Genetic Genealogy Success: Profiles and Family Trees

Our own Paul Woodbury follows up on his article about the journey of a DNA sample with a discussion of how profiles and family trees are the foundations for genetic genealogy success. This article is a reprint from a recent issue of the National Genealogical Society Magazine and is published here with permission.

In my previous article, “From Spit to Screen: The Journey of a DNA Sample” I described the journey of a DNA sample from the moment a sample is taken to the moment a test taker receives notification that their test results are ready for review. From mailing to completion of processing, a customer may need to wait several weeks or months until their test results are ready to be used for genealogical research. Still, even while waiting, test takers can perform several tasks to create a strong foundation for future genetic genealogy research success. Creating a detailed profile, preparing lists of ancestral surnames or locations, and uploading a family tree can encourage collaboration, open doors of discovery for others. These steps can also lead to efficient corroboration of proposed family trees, and spur genealogical discovery once test results complete processing.

A detailed profile can help avoid unwanted communication centered around questions of identity and instead guide and invite collaboration on research topics and families of interest.

A test taker’s profile is akin to a job application or resume; it is a tool that helps convince genetic cousins that they do want to work and collaborate with the user. Collaboration is an essential element of all genealogical research, including genetic genealogy, where many genealogical mysteries are solved using the details, information, and family trees shared in the profiles of genetic cousins. While a strong profile can certainly help others in their journeys of genealogical discovery, it can also help a user themselves, by encouraging and inviting efficient and focused collaboration. Each DNA testing company offers the option to customize a profile with an image, description, and explanation of research interests.

When a test taker’s profile includes a photo, genetic cousins may consider the user more approachable and open to contact. When a test taker’s profile includes additional details such as age, residence, interests, family surnames, or other information, this can help other genetic cousins avoid unnecessary communication just to figure out a user’s identity. As a result, those with more complete profiles often experience less unwanted communication centered around identity and instead invite more helpful communication centered around specific research questions and goals for genealogical research. At the same time, the information that a user wishes to share should be balanced against their privacy preferences and comfort level.

In addition to profile images and descriptions, each DNA testing company offers additional options to enhance a user’s profile:

23andMe

At 23andMe, users have the option of publishing their current residence, places where their ancestors were born (including survey results regarding their four grandparents), surnames in their family tree, and links to online family trees at other sites. While 23andMe prompts users to fill out these profile items when they are setting up an account, these responses can be edited at any time by reviewing and editing a user’s account settings and their “enhanced profile.” The current residences reported by 23andMe customers in their profiles are used to create the map view of a user’s genetic cousin match list: a demonstration of the geographic distribution of genetic cousins.

The results of the grandparent birthplace survey are published on user-profiles and can aid others in quickly determining which ancestral lines may be the source of a shared relationship. In addition to the results of this survey, users can publish a list of other birthplaces from older generations. These, too, are published on a user’s profile and are searchable within the database of genetic cousins. For example, performing a search at 23andMe in the “DNA Relatives” list for “Alabama” will return all individuals who have reported Alabama as a birthplace for one of their ancestors.

23andMe customers may also provide a list of family surnames in conjunction with their test results. These surnames are also searchable in the general database, along with the names of genetic cousins. For example, a search of the “DNA Relatives” list for the Woodbury surname will return all individuals with the Woodbury surname listed in their profile of ancestral names. Still, it will also return all matches carrying the Woodbury surname regardless of whether it is included in their profile list or not. 23andMe users can provide a link in their profile to an online family tree. Because 23andMe no longer supports their tree-building tools, users must link their family tree to outside sources. These links can greatly assist others in identifying common ancestors and determining the nature of a genetic relationship. Finally, 23andMe customers can share an introduction and description to be published and shared with their matches.

When users at 23andMe report their current residence, it enables other users to analyze the geographic distribution of their genetic cousins.

Users can adust other publication preferences at 23andMe in the settings and preferences for a user’s involvement in the DNA Relatives database. These adjustments include how your name is shown, whether or not to display your birth year, the sex you wish to be displayed, as well as if you would like to display your ethnicity percentages and matching DNA segments. These latter display features can be helpful to others in determining the nature of a relationship.

MyHeritage

Users of MyHeritage are asked to fill out a member profile that displays their age and country of residence. Nevertheless, the most useful foundation and preparation that test-takers can pursue here is linking a family tree to their test results. When MyHeritage test-takers link a family tree to their test results, the website will generate hints regarding shared ancestors (SmartMatches) between the trees of common matches. MyHeritage’s Theory of Family Relativity will also take the details from trees and compare them against their larger database of trees and records to propose theories of how two individuals might be related. The details are compared even if the proposed common ancestors between two individuals are not included in their respective family trees. When MyHeritage users attach family trees to their test results, the website will also generate lists of shared surnames and shared ancestral locations described in the match list and match profiles. Users can search for specific surnames or can filter by shared surnames or locations.

When a user and their genetic cousin both attach family trees to their DNA test results at MyHeritage, the website will report lists of common surnames, Smart Matches, and common ancestral locations as part of that genetic cousin’s entry in the match list and genetic cousin profile.

Ancestry

At Ancestry.com, customers can adjust their account profile to show their age, residence, languages, family history experience, and research interests. These details can help encourage collaboration and correspondence with researchers sharing similar interests. Publishing residences also enables the map view of DNA test results where users can see the geographic distribution of their genetic cousins.

When users attach family trees to their test results at Ancestry, the website will generate ThruLines reports of other genetic cousins also descending from commonly reported ancestors.

Beyond the basic member profile, users can also adjust settings related to how they appear in others’ match lists as part of the DNA settings, including their display name and if other users can see their ethnicity estimate and genetic communities.

Perhaps the most useful setting at AncestryDNA is the ability to link a test to a family tree. AncestryDNA will generate hints regarding shared ancestors with other genetic cousins when users link family trees to their DNA test results. They will also present genetic cousins who also descend from shared ancestors as part of their ThruLines tool. AncestryDNA’s ThruLines incorporates data from the family trees of matches and utilizes other family trees to link matches to each other even if their common ancestor is not in both family trees. Finally, when users link a family tree to their AncestryDNA test results, Ancestry will highlight shared surnames and locations in the family trees of other genetic cousins, offering clues regarding likely sources of shared DNA. These shared surnames and shared locations are searchable as part of the AncestryDNA search and filter functions.

Family Tree DNA

Family Tree DNA customers can fill out a profile, introduction, and other associated information in their account settings. Customers here should ensure that they publish an updated email address to enable communication with DNA matches. Family Tree DNA also offers the option to select an account beneficiary who can continue to manage the account and any remaining DNA sample if a test taker dies.

When a user and their genetic cousin both publish lists of ancestral surnames at Family Tree DNA, shared surnames between the user and their match will appear in bold on the user’s match list.

Under the “Genealogy” section of Family Tree DNA’s account settings, users can add a list of ancestral surnames and associated locations as well as information on their earliest known maternal and paternal ancestors. Surname and location information is beneficial when exploring genetic cousin match lists as any surnames shared in common between a test taker and a match is listed in bold. These surname lists can also be queried as part of Family Tree DNA’s surname searches and filters. Meanwhile, user-provided information on the earliest known paternal and maternal relatives can greatly aid in the interpretation of Y-DNA test results and mitochondrial DNA test results. Y-DNA is inherited from father to son in a direct line of paternal inheritance. Mitochondrial DNA is inherited from a mother to her children in a direct maternal line of inheritance. Therefore, one should focus on the earliest known patrilineal (the father of the father the of father) ancestor and earliest known matrilineal (the mother of the mother of the mother) ancestor as opposed to the earliest known paternal relative or the earliest known maternal relative from any ancestral line.

Finally, Family Tree DNA offers the option to upload or build a family tree to associate with a user’s test results under the “MyTree” section. Surnames included in a tree are not searchable in the Family Tree DNA database as the surname lists are. Also, the inclusion of a family tree does not generate automated hints at Ancestry or MyHeritage. Nevertheless, searches can be performed in individual trees for specific names or surnames to quickly locate the position and identity of a common ancestor. Thus, the inclusion of family trees at Family Tree DNA can still help others better determine the nature of their shared relationship to a test taker.

Profile and Family Tree

Setting up a detailed profile at each DNA testing company and, where possible, attaching a family tree to DNA test results lays a strong foundation for future success in genetic genealogy research efforts. A well-crafted profile can direct and invite desired collaboration. The inclusion of residence information can reveal the geographic distribution of DNA matches. Lists of surnames and ancestral locations can generate hints and enable database searching for others. Finally, linked family trees can generate hints of relationship, ease interpretation of key genetic cousins, and aid in identifying which genetic cousins are most likely related through ancestral lines of interest. Users should only share after considering their comfort level and privacy preferences, and each company provides multiple options for setting individual preferences to align with personal privacy concerns.

Regardless of how much a user chooses to share or not share, consideration of these steps stands to benefit all genetic genealogy researchers. As more test takers share details regarding their age, residence, origins, ancestry, and genealogy, all benefit from more readily helpful information, which unlocks the doors to genealogical analysis, interpretation, and discovery.

Getting a DNA test is a great way to start, but completing the journey requires hard work, collaboration, and access to the latest tools and services. If you get stuck and need some assistance, our genealogists will work with you to find success. Contact us today for a free quote!

maj 12, 2021 by Paul - Legacy Tree Genealogists Researcher 1 Comment

From Spit to Screen: The Journey of a DNA Sample

One of our researchers, Paul Woodbury, describes the journey of a DNA sample from the instant the sample is taken until it is analyzed in the laboratory. The following article is a reprint from the July-September 2020 issue of the National Genealogical Society Magazine and is published here with permission.

This 23andMe collection kit and similar AncestryDNA collection kits rely on saliva collection. Hong Chang Bum, “IMG_0901” (https://www.flickr.com/photos/hongiiv/3128937011). Attribution-NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0) license.

How does DNA testing actually work? How can spitting into a tube result in an ethnicity estimate, a list of genetic cousins, and other DNA data? This article reviews the technology that enables genetic genealogy and the five-step process that transforms a saliva sample into a comprehensive genetic report: collection, extraction, amplification, testing, and data analysis (1).

Collection

Complete copies of the human genome are carried by most of the trillions of cells in the human body. While red blood cells and some skin, hair, and nail cells do not carry nuclear DNA, nearly any other type of cell can be sampled for DNA analysis.

In the early days of genetic genealogy testing, companies utilized blood samples. Now, most genetic genealogy testing companies collect DNA through less invasive and more convenient spit or cheek swab kits. The DNA obtained from these kits originates from white blood cells in saliva and buccal epithelial (cheek) cells.

Most DNA testing companies discourage testers from eating, smoking, drinking, chewing gum, brushing teeth, or using mouthwash in the half-hour before taking a DNA test. While foreign particles from food, liquids, toothpaste, and tobacco do not alter DNA, they can mask it or cause it to degrade(2).

Testing companies also warn against activities that might cause cross-contamination of a sample. For swab collection kits like those used by Family Tree DNA and MyHeritage, testers should be careful not to drop the swab in anything that might contaminate the sample, touch the collection swab with their hands, or brush it against other objects. When performing spit collection tests like those utilized by AncestryDNA and 23andMe, testers should try to collect all the necessary saliva at once to avoid contamination from foreign materials in the air.

DNA testers should register their kit with the corresponding testing service to ensure later access to the test results. Some labs will not process kits that have not been registered.

This now obsolete National Genographic collection kit is similar to Family Tree DNA and MyHeritage collection kits which rely on buccal swabs. Paulo O, “Genographic Kit andAntares info kit” (https://www.flickr.com/photos/brownpau/8653415433). Attribution 2.0 Generic (CC BY 2.0) license.

While DNA can sometimes last very long in the right environment, degradation can occur due to proteins that destroy DNA, foreign materials like food, bacteria, and other chemicals, or large fluctuations in temperature. To prevent degradation and to keep DNA intact from the time it is collected to the time it is ready to be analyzed, sample collection kits typically include a liquid buffer solution.

These solutions stabilize the cells, sometimes include antibacterial elements, inhibit the activity of proteins that would degrade the DNA, and preserve the DNA in a stable pH solution which is not as easily affected by fluctuations in temperature. With such a solution, DNA can be preserved while it is prepared, mailed, stored, and eventually processed by a lab.

Isolation and Extraction of DNA

Every DNA collection sample has hundreds of thousands of cells, each carrying a copy of the tester’s DNA, but these samples also contain proteins, chemicals, fats, water, and a host of other biological materials. Before DNA can be analyzed, it must be isolated from all of these other materials.

First, cells are broken open with a detergent. Cells are held together by a membrane composed of two layers of fat called a lipid bilayer. Just as detergents interact with fats in water, they interact with the lipids in cell membranes to break them open and release the contents of the cell into a solution.

Next, certain cellular components are destroyed. Cells carry proteins that interact with DNA as well as other proteins that destroy free-floating DNA. Cells also include free-floating RNA, which is similar to DNA and can cause problems in later DNA analysis. To overcome these problems, a protease (an enzyme that destroys proteins) and an RNAse (an enzyme that destroys RNA) are added to the sample.

Finally, salt is added to the mixture to make all the debris from the proteins, lipids, and RNA clump together. When the solution is centrifuged (spun in a circle at very high speeds), this debris clumps together and collects at the bottom of a sample tube, leaving the DNA floating in the solution.

After most of the debris is removed from the sample, the DNA is further isolated from the detergents, proteins, salts, and reagents used in the first step. Alcohol is added to the sample, and since DNA is insoluble in alcohol, a subsequent round of centrifuging isolates the DNA in a clump at the bottom of the test tube. The DNA has been isolated.

In order to obtain a sufficient amount of DNA for testing, companies amplify the DNA from the original sample through Polymerase Chain Reaction protocols. Enzoklop, “Polymerase chain reaction” https://commons.wikimedia.org/wiki/File:Polymerase_chain_reaction.svg). Creative Commons Attribution-Share Alike 3.0 Unported license.

Amplification

The technologies used by genetic genealogy testing companies require a large amount of DNA for successful analysis—much more DNA than what is present in the initial sample provided by a customer. For this reason, labs utilize Polymerase Chain Reaction (PCR) protocols to amplify or copy the DNA being analyzed. DNA replicating proteins, free-floating DNA bases, and DNA primer sequences are added to a sample to create an environment conducive to DNA replication.

Next, the sample is submitted to several cycles of temperature variations. During this process, the DNA denatures or “melts” into single strands, DNA primers bind to complementary strands of DNA, and DNA polymerase (a DNA-building and replicating protein) recruits free-floating bases and extends the DNA, making a new copy.

In the first temperature variation cycle, one strand of DNA duplicates into two strands. The number of copies of the DNA doubles with every cycle, and within a few hours, it is possible to obtain millions of copies of a test taker’s DNA from the initial sample.

Testing

At this point, the way in which DNA is tested depends on the type of DNA test being performed. Autosomal DNA tests, Y-DNA tests, and mtDNA tests are treated differently. Because autosomal DNA testing is the most common type of testing, this article reviews the protocols for SNP chip microarrays.

Single Nucleotide Polymorphisms (SNPs) are locations in DNA that are known to be hotspots of variation in the general population. Rather than testing all of an individual’s DNA, testing companies typically test between 400,000 and 700,000 SNP markers across the genome. Because each individual has two copies of DNA—one from the mother and one from the father—there are three possibilities for a genotype at any given SNP marker: both copies could carry one variation, they could both carry the other variation, or they might carry different variations.

For example, if an SNP marker has two typical values of C or G, it is possible that an individual could have a genotype of CC, GG, or CG. An individual with the same SNP variation on both copies of DNA is homozygous at that location. A person with different variations on the two copies of DNA is heterozygous at that location.

Genetic genealogy tests rely on SNP Chip testing to query SNP markers for a test taker. Each testing company uses chips manufactured by Illumina, a biotechnology company. These “chips” are glass plates with microscopic silicon beads attached to predefined and indexed locations(3).

Each silicon bead, in turn, has several copies of a manufactured short single-stranded segment of DNA attached to it. These short sequences are complementary to a sequence in human DNA immediately preceding the location of a SNP.

In order to test SNP locations, a tester’s sample is treated to shear or break the DNA into smaller fragments and denatured to make it single-stranded. Next, the DNA is washed over the chip, where it binds with the complimentary manufactured DNA just short of the location of the SNP. Then DNA Polymerase and modified A, T, G, and C nucleotides with fluorescent tags are introduced. The sample DNA is washed away, leaving the manufactured strands with one more base and fluorescent tags indicating which base has been added.

The chip is then submitted to a laser reader, which causes the DNA strands to fluoresce red (homozygous for one variation), green (homozygous for the other variation), or yellow heterozygous). A scanning software records and interprets the fluorescence. It determines the color of each locus, determines what the fluorescence means for that location, and then uses the index to associate the result with a corresponding location in the genome.

Finally, the software program records the values, A, T, G, or C, that have been detected for each of the 500,000-700,000 locations that have been analyzed into a raw data file.

Once the DNA has been extended by one fluorescently labeled base, it is submitted to a laser scan. Green indicates homozygosity for one version of the SNP, red indicates homozygosity for the other version of the SNP, and yellow or orange indicates heterozygosity. Each color for each site is interpreted by software and associated with a particular location in the genome. Kat Masback, “Microarray, AV-0101-5194 Dr. Jason Kang, NCI (Lance Miller)” (https://www.flickr.com/photos/[email protected]/3341761068). Creative Commons Attribution-ShareAlike 2.0 Generic license.

Data Processing

Autosomal DNA raw data results are composed of a list of several hundred thousand marker locations and two base values (A, T, G, or C) for the corresponding locations (one maternal and one paternal). In and of themselves, these values have limited usefulness for genealogical research. It is a comparison against reference datasets and customer databases that generate the most useful elements of genetic genealogy tests: ethnicity admixture estimates and cousin matching.

Ethnicity admixture estimates for autosomal DNA tests are obtained by comparison of a raw data file against a “reference panel” of samples for individuals with known ancestry from particular regions of the world. Prevalence of DNA marker values in specific populations is used to assign portions of a test taker’s DNA to different ethnicities or regions.

Autosomal DNA matches are identified by comparing the markers of a test subject against the markers of other tested customers in the database. When two individuals share long sequences of consecutive markers on at least one DNA copy, they share a “segment” of DNA from a recent common ancestor. Based on the size, location, and the number of segments two individuals share, it is possible to estimate how closely two individuals are related to each other.

Conclusion

Once raw data has been incorporated into a company’s system and compared against other customers and reference datasets, the test taker receives a notification that DNA test results have completed processing. From spit to screen, the DNA sample has been collected, isolated, amplified, tested, and processed to provide the researcher with useful information for a genealogical investigation.

Websites cited in this article were viewed on 8 June 2020.

1. “What Happens To My DNA Sample At The Lab?” 23andMe (https://customercare.23andme.com/hc/en-us/articles/202904590-What-Happens-to-My-DNA-Sample-at-the-Lab).

3. “Infinium™ Global Screening Array-24 v3.0 BeadChip,” Illumina (https://science-docs.illumina.com/documents/Microarray/infinium-globalscreening-array-data-sheet-370-2016-016/infinium-commercial-gsa-ds-370-2016-016.pdf).

Getting a DNA test is a great way to start your genealogy journey, but what comes next? Hire a professional at Legacy Tree and our genealogists will work with you to discover your family history. Contact us today for a free quote!

februar 1, 2021 by Paul - Legacy Tree Genealogists Researcher 2 Comments

The Biological Journey of DNA Inheritance: Meiosis to Fertilization

Understanding the biologial journey of genetic inheritance can help in the interpretation of DNA evidence for genealogy research.

*This article originally appeared in NGS Magazine, and is reprinted with permission.

Different DNA inheritance paths can help solve genealogical mysteries. These unique inheritance patterns provide important context for interpretation of DNA test results and enable genealogical discoveries, but why is DNA inherited the way it is? What underlying biological processes explain the inheritance patterns of different types of DNA? What are the natural laws that govern genetic inheritance paths?

Genealogists commonly utilize historical, social, governmental and legal context to understand and interpret the records created regarding ancestors. Just as an understanding of the laws of a particular time period and place can aid in interpretation of records created for an ancestor, understanding the biological laws governing genetic inheritance can help in later interpretation of DNA evidence for genealogical purposes.

An Introduction to DNA

DNA is composed of four bases: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). Long strands of these bases pair with each other (A with T and G with C) to form a double helix. Attribution: Zephyris, “DNA Structure+Key+Labelled,” https://en.wikipedia.org/wiki/File:DNA_Structure%2BKey%2BLabelled.pn_NoBB.png. CC-SA 3.0

DNA provides the blueprint for all life and is written with four biological “characters” called bases: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). These bases are linked together in long strands to form an “instruction manual” for the human body. To protect this important biological code from damage, the strands of DNA align with complementary strands: A pairing with T and G pairing with C. The result is a double helix structure composed of millions of “basepairs.” A human genome (or a complete set of human DNA) contains approximately 6.4 billion basepairs.

Genetic Records, Archives, Transcription and Translation

The human genome is like an instruction manual that is divided into twenty-three “volumes” known as chromosomes. There are two “editions” of each volume of the instruction manual: a paternal edition inherited from an individual’s father, and a maternal edition inherited from an individual’s mother. The instruction manual also includes an “addendum” of mitochondrial DNA. The twenty-three chromosome volumes which form the majority of the genome instruction manual are housed as a single collection in an “archive” called the nucleus. The mitochondrial DNA addendum, meanwhile, is stored outside of the nucleus in locations called mitochondria.

Most human DNA, including a copy of all twenty-three pairs of chromosomes, is stored in the nucleus of the cell which serves as a type of cellular archive. Meanwhile, each mitochondrion has multiple copies of the mitochondrial DNA and most cells have multiple mitochondria. Attribution: OpenStax, “Animal Cell and Components,” modified, https://commons.wikimedia.org/wiki/File:0312_Animal_Cell_and_Components.jpg. CC-A 4.0

The human body is composed of trillions of cells and each of those cells (with a few exceptions) has a nucleus with a copy of the paternal and maternal editions of all twenty-three chromosome volumes. Each cell also has multiple mitochondria which serve as cellular powerhouses; each mitochondrion carries multiple copies of the mitochondrial DNA addendum. Though each cell contains a complete genome instruction manual, only parts of the manual are read depending on the type of cell. As with historic archives, consultation of the original DNA records is not possible outside of the nucleus archive. Instead portions of the DNA instructions read by specialized protein machines which “transcribe” select portions of the genome into RNA copies. These RNA transcriptions can be distributed outside of the archive and “translated” into sequences of amino acids. Chains of amino acids interact with each other to form proteins. The shape of proteins governs their function. Processes for reading, transcribing and translating mitochondrial DNA are similar to those employed in the nucleus.

Portions of the DNA are transcribed in the nucleus into RNA copies, These RNA strands can be transported out of the nucleus and used as a template for translation from RNA code to protein synthesis. Attribution: Dhorspool, “Central Dogma of Molecular Biochemistry with Enzymes,” https://commons.wikimedia.org/wiki/File:Central_Dogma_of_Molecular_Biochemistry_with_Enzymes.jpg. CC-SA 3.0

Mitosis, Meiosis, Mutations

Human bodies grow, change, and develop through the continual replacement and division of cells – a process called mitosis. When a cell divides, the entire genome is copied. Each edition of each chromosome volume is replicated and bound with its duplicate at a part of the DNA strand called the centromere. Then, the nucleus is demolished. Next, a copy of each edition of each chromosome volume is distributed to opposite sides of the cell. Two new nuclei (archives) are built around these new copies of the instruction manual, and the cell then divides into two new cells. Thus, each daughter cell carries a complete copy of the genome. This process of genetic replication and division occurs millions of times each day.

During mitosis or cell division, DNA is replicated and a complete set of the genome is sent to the two resulting daughter cells. Attribution: Ali Zifan, “Mitosis Stages,” https://commons.wikimedia.org/wiki/File:Mitosis_Stages.svg. CC-SA 4.0

Mitochondria replicate independently within each cell and contain multiple copies of mitochondrial DNA. When a mitochondrion becomes too large, it divides in half. Some copies of the mtDNA are included in one new mitochondrion and some copies are preserved in the other. When a cell divides, some mitochondria remain in one cell and other mitochondria remain in the other.

Given how often the genome is replicated, it is no surprise that sometimes errors are made in the replication of DNA. Some errors or mutations can have a detrimental effect and might lead to cell death. Others might affect the shape of a protein and its resulting function or prevalence. Other mutations have little to no effect and are passed on to descendant cells. The introduction of occasional mutations makes genetic genealogy possible. Any human individual shares approximately 99.9% of their DNA with all other humans. It is the .1% variation between humans and the associated inherited mutations that enable investigation, analysis and determination of the closeness of genealogical relationships.

Usually, when cells divide, a complete copy of the genome is passed on to both daughter cells. However, this is not the case for germ-line cells: sperm cells and egg cells. A process called meiosis results in sperm and egg cells with just a single edition of the genome rather than the two editions held by most other cells. Meiosis starts in much the same way as mitosis. Each chromosome is duplicated so that there are two copies of each edition of each of the twenty-three chromosome volumes. The two copies of each edition are bound together at the centromere. However, instead of separating to opposite sides of the cell, the paternal editions of each chromosome pair off with the maternal editions of each chromosome and become closely associated. A process called recombination often results in parts of a maternal edition of any given chromosome being swapped with corresponding parts of a paternal edition of the same chromosome.

After this exchange of information, the nucleus disintegrates, and the altered editions of each chromosome are pulled to opposite sides of the cell. One set of altered editions is pulled by its centromere to one side of the cell and the other set of altered editions is pulled by its centromere to the other side of the cell. The cell divides and the resulting cells divide again. During this second round of cell division, there is no replication of the editions and instead, an edition of each chromosome volume is pulled to opposite sides of the cell. The result of meiosis is four cells with a single edition of each chromosome volume – half the normal amount carried by most cells. In females, one large egg is created with three smaller cells which typically die. In males, four sperm cells are created. In any given cell the single edition of any given chromosome volume could be the maternal edition, could be the paternal edition, or could be (and often is) a compilation of information pulled from both the maternal and paternal edition of the chromosome.

During meiosis, DNA undergoes recombination, and the undergoes two cell divisions. The result is four cells with one copy of each chromosome – half the normal amount for a typical human cell. Attribution: Ali Zifan, “Meiosis Stages,” https://commons.wikimedia.org/wiki/File:Meiosis_Stages.svg, CC-SA 4.0

Sex Chromosomes – Special Editions

Human DNA is divided into twenty-three sets of chromosomes. Each chromosome has two “editions” one maternal and one paternal.

Chromosome volumes 1-22 are very similar regardless of the edition consulted (maternal or paternal). The paternal and maternal editions of chromosome volume 23, meanwhile, can be quite different. In females, the paternal and maternal editions are X-chromosomes which are fairly similar. In males, meanwhile, chromosome volume 23 has two very different editions: A maternal X-chromosome edition and a much smaller paternal Y-chromosome edition. When meiosis occurs in females, the X-chromosomes line up and undergo normal recombination. The resulting four cells from the process each contain an X-chromosome. In males, meanwhile, the Y-chromosome and the X-chromosome line up but only undergo very limited recombination. Therefore, the Y-DNA and X-DNA are passed on essentially unchanged to daughter cells. Two of the four cells resulting from meiosis in males will contain Y-chromosomes and two will contain X-chromosomes.

Fertilization

During the process of human reproduction, millions of sperm cells approach an egg in a race to fertilize it. When an egg and a sperm combine, they form a zygote which has the potential to eventually develop into a human being – the next generation. If the sperm cell carried a Y-chromosome, then the resulting zygote could develop into a biological male. If the sperm cell carried an X-chromosome, then the resulting zygote could develop into a biological female.

While sperm cells do carry mitochondria and associated DNA, when the sperm cell penetrates the egg, the cellular contents of the sperm (including the mitochondria) are destroyed. Thus, except in rare cases, the only surviving mitochondrial DNA originates from the egg and is thus maternally inherited. The nucleus from the sperm, however, remains intact until it merges with the egg’s nucleus at which point the process of cell division can begin in the development of a fetus.

Genetic Inheritance and DNA: Y-DNA and X-DNA Inheritance

Y-DNA and X-DNA inheritance can be explained by the process of meiosis. In males, this process results in the creation of four sperm, two of which carry a Y-chromosome and two of which carry an X-chromosome. In females, the process of meiosis results in the formation of an egg cell which contains an X-chromosome. If the fertilizing sperm contains a Y-chromosome the resulting fetus will be male. If it contains an X-chromosome the resulting fetus will be female.

X-DNA inheritance and autosomal DNA inheritance can also be partially explained by the process of recombination in which each maternally inherited chromosome aligns with each paternally inherited chromosome and might exchange or shuffle genetic material into novel chromosome variants or editions. As a result, while each individual inherits 50% of their DNA from each parent in the form of a complete set of paternal and maternal chromosomes. Inheritance from more distant generations of ancestors is more random. For this same reason, X-DNA might, but may not necessarily be inherited from a specific subset of ancestors related through maternal lines or alternating maternal-paternal lines.

Mitochondrial DNA inheritance can be explained by the mechanics of fertilization which preserve mitochondria and associated DNA from egg cells but destroy mitochondria and associated DNA from paternal sperm cells.

Understanding these basic laws of genetic inheritance can help in the interpretation of DNA evidence for genealogy research.

Do you have a genetic genealogy mystery you would like help resolving? Contact Legacy Tree Genealogists today. Our team is experienced at utilizing DNA evidence from all major testing companies in combination with thorough records research to break down the genealogy “brick walls” in your family tree.

How to Understand Your Closest Autosomal DNA Test Matches

How do companies create and prioritize your autosomal DNA test match lists?

Evaluation of Closest Genetic Cousins (Over About 200 cM) Using Autosomal DNA Test Matches

Do you recognize any of your closest autosomal DNA test matches?

Do your matches have surnames or family trees that clarify their likely relationship?

Do your close-known relatives share appropriate amounts of DNA?

Do your first cousins share amounts of DNA appropriate for first cousins, or could they be half-first cousins?

Do you have too many close autosomal DNA test matches?

Do you have no close matches?

6 Signs of Misattributed Parentage in Your Genetic Family Tree

Clue #1 Unexpected Ethnicity Results

PRO TIP:

Clue #2 Y-DNA Testing Anomalies

PRO TIP:

Clue #3 No shared DNA with close relatives who have also tested

Example Cousin Scenario 1 and 2

PRO TIP:

Clue #4 Lower than expected amounts of shared DNA with a known relative

PRO TIP:

Example Cousin Scenario 3, 4, 5

Clue #5 Close unknown genetic cousins

Example Cousin Scenario 6, 7

Clue #6 No genetic connections to a particular branch of your family

What Next?

Nine Tips for Successful Adoption Research with Genetic Genealogy

1. Gather as much background information, context, and records as you can to start your adoption research

Interview Those Involved

Request Records

Historic Adoption

Conception Analysis

2. Be open minded regarding the accuracy of background information

False Information

Inaccurate Information

Use “Known” Parents for Research

3. DNA Test at multiple companies

Autosomal DNA Testing

X-DNA Testing

Y-DNA Testing

Mitochondrial DNA Testing

4. DNA Target test others

5. Try to distinguish paternal vs. maternal relatives

6. Collaborate with genetic cousins

7. Be patient with yourself, your matches, and others in your collaboration efforts

8. Use DNA and documents in adoption research to find the right people in the right place at the right time

9. Have a professional genealogist review your adoption research work

Five Ways to Use the New DNA Coverage Estimator Tool at DNA Painter

1. Estimate Your Ancestor’s Coverage in a Single Testing Database

2. Prioritize the Genetic Cousins with Whom You Should Collaborate

3. Prioritize the Relatives You Should Invite to Test or Transfer

4. Estimate the Amount of DNA Your Ancestor Shared with a Genetic Cousin

Estimates are…Estimates

5. Estimate the Amount of DNA Your Ancestor Shared with a Deceased Relative

Introduction to Ethnicity Admixture

What is ethnicity?

How it works

Genetic Communities, Recent Ancestor Locations, and Genetic Groups

Why the differences?

Conclusion

Eight Steps to Pursue with New Autosomal DNA Test Results

Set up a profile and attach a family tree

Review ethnicity admixture reports

Review the closest genetic cousins

Consider shared matches

Contact genetic cousins

Take notes

Search and filter

Explore other company tools

Conclusion

Where to Test? Genetic Genealogy Testing Options

23andMe

AncestryDNA

FamilyTreeDNA

MyHeritage

Where to test? Everywhere!

Foundations for Genetic Genealogy Success: Profiles and Family Trees

23andMe

MyHeritage

Ancestry

Family Tree DNA

Profile and Family Tree