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The Who, What, Where, and Why of Genetic Genealogy Testing

April 17, 2015 by Paul - Legacy Tree Genealogists Researcher 20 Comments

Genetic Genealogy TestingIn the future, genetic testing will become an increasingly integral part of the fields of family history and genealogy. Even now, genetic testing is sometimes considered necessary as part of the reasonably exhaustive search required for the genealogical proof standard.

In this introduction to DNA testing for family history purposes, we'll outline how DNA tests work, provide an explanation of the tests available and the companies that offer them, and finally, explain what results you can expect and how they can be used to answer family history questions.

The Companies

There are four main companies that offer tests which are useful for family history. In order for a DNA test to be useful for genealogical investigation, it must analyze informative markers on the DNA and it must connect the results to a database of other tested individuals. Although there are many companies that offer DNA testing for some type of ancestry analysis, only four of these companies meet the aforementioned criteria:  MyHeritage DNA, Ancestry.com, Family Tree DNA, and 23andMe.

Taking the Test

Each of these companies use a similar collection method. After a customer purchases a test, they will receive a kit in the mail. Ancestry.com and 23andMe both use a saliva collection tube, whereas MyHeritage DNA and FamilyTreeDNA both use a cheek swab. These non-invasive collection kits do not require the subject to draw blood. They are simple to use and come with a detailed set of instructions.

MyHeritage DNA, 23andMe and Ancestry.com require creation of an account in order for the test to be fully processed. FamilyTreeDNA will request an email address where the results can be sent.

Test Types

There are three types of tests offered for family history purposes: Y-chromosome tests, mitochondrial DNA tests, and autosomal DNA tests. The meaning behind these names will be explored below in the section titled “DNA Types.”

All four companies offer an autosomal DNA test, and this is the only test offered at Ancestry.com, MyHeritage DNA and 23andMe. FamilyTreeDNA’s autosomal DNA test is called the “Family Finder.” In addition to the Family Finder autosomal DNA test, FamilyTreeDNA also offers several Y-chromosome and mitochondrial DNA tests.

Although 23andMe includes some analysis of the Y-chromosome and mitochondrial DNA as part of their product, this analysis only investigates the very deep ancestry of these DNA types. Sometimes deep ancestry information can offer clues, but it does not provide enough information to draw genealogical conclusions.

The test results from each of the companies differ from one another in some aspects, but have some basic shared elements. When your test results are ready, you will receive a notification to your email and you will be able to view them by logging into your account. Autosomal tests include ancestral ethnicity estimates as well as a list of genetic cousins or matches who are estimated relatives based on the amount of DNA that you share in common with them. Each company offers different tools for additional analysis of autosomal DNA test results. MyHeritage allows users the option to upload their raw DNA from other companies in order to receive an ethnicity report and genetic matching in their database.

Y-DNA and mitochondrial DNA tests also include some basic information about the geographic distribution of your DNA types, and also include a list of relatives based on the markers that you share in common. These test results also include a summary of the mutations on your own Y-chromosome or mitochondrial DNA that make them unique from other lineages.

DNA Types

The Y-chromosome is only carried by males and is inherited in a line of direct paternal descent. A male receives his Y-chromosome from his father who inherited it from his father, and on and on. Occasional mutations help to distinguish different Y-chromosome lineages. Because surnames are often inherited in a similar pattern in many cultures, two individuals with the same surname and similar Y-chromosome signatures share a common direct line paternal ancestor. Likewise, two individuals with different surnames but who share the same Y-chromosome signature share a common direct line paternal ancestor. This situation may be indicative of a “non-paternal event (NPE),” which could include an undocumented adoption, illegitimacy, a surname change, or any number of other situations which might result in the paternal surname not being passed to both lines of descent.

Mitochondrial DNA is carried by both males and females, but it is only passed on by females. Therefore, mitochondrial DNA is inherited along the direct maternal line. An individual receives their mitochondrial DNA from their mother who received it from her mother. Occasional mutations help to distinguish different mitochondrial DNA lineages. If two individuals share a mitochondrial DNA signature it may be indicative of shared maternal ancestry. Because mitochondrial DNA is much smaller than any other type of DNA, and because it undergoes fewer mutations over time, it is harder to make genealogical discoveries with this type of test. It is best used to offer support for genealogical hypotheses.

Autosomal DNA tests analyze portions of the DNA that are inherited both paternally and maternally. Each person receives half of their autosomal DNA from their mother and half from their father. Autosomal DNA undergoes a process called recombination, which shuffles the maternally and paternally inherited copies of DNA before passing them on to the next generation. Each person receives exactly half of their autosomal DNA from each parent, but only approximate percentages can be applied to more distant generations of ancestors due to the random nature of recombination. Each individual shares about 25 percent of their DNA with each grandparent and half that amount for each subsequent generation. Individuals who share large identical segments of autosomal DNA most likely share a recent common ancestor.

The X-chromosome is one other type of DNA that has a unique inheritance pattern. Males have one X-chromosome from their mother. Females have two X-chromosomes: one from their mother and one from their father. The X-chromosome undergoes recombination in females, but not in males. Though the X-chromosome cannot be assigned to a specific line of descent, it can be used to eliminate individuals from a person’s tree as possible common ancestors to their matches. The X-chromosome is tested at each of the companies as part of their autosomal DNA tests.

Reasons to Test

Genetic genealogy tests can help confirm or refute genealogical hypotheses, open up new avenues of research, or they may not be helpful at all. However, as the databases grow and as more people test, the last result in this list is becoming increasingly uncommon.

DNA testing can be useful for answering questions regarding adoption, illegitimacy, unknown or mis-attributed parentage, name changes, immigration, and many other instances of difficult-to-trace ancestry.

While DNA tests have the ability to help investigation in these difficult situations, they also have the ability to reveal well-kept family secrets. Whenever a DNA test is taken, the subject should recognize the possibility of discovering previously unexpected relationships through undocumented adoptions and illegitimacies. Many times the discovery of these events can be surprising and may drastically change the way you view and approach your family history. Testing companies and private researchers do not claim responsibility for these discoveries and the impact that they may have on individuals and families.

Genetic Genealogy Success

Many adoptees have successfully identified their birth parents through genetic testing and other available resources. However, genetic testing can also be helpful for genealogical questions. Many have successfully used Y-DNA testing in conjunction with autosomal DNA and the historical record to identify fathers of illegitimate ancestors. Others have used autosomal testing to overcome recent genealogical brick walls. Yet others have used mitochondrial DNA to support descent from common maternal ancestors and to confirm or refute family legends regarding African or Native American ancestry.

In one recent case, we were able to reveal the identity of a client’s 2nd great grandfather through autosomal testing. A concealed illegitimacy had prevented previous contact with this part of the client’s family and as a result of DNA testing, we were able to extend the client’s ancestry several generations. Though we were able to answer the client’s research question, this research also opened new avenues of investigation since no member of the family has yet been able to determine the origin and parentage of their common 2nd great-grandfather who was born in the early 1850s in Missouri. DNA testing and collaboration with these newfound cousins may help to reveal this individual’s ancestry through future research.

Applications of DNA testing to genealogical investigation are many and varied, and they are also frequently successful. However, even when tests do not yield immediate results, as more people test and more matches are identified, genetic genealogy tests become sources that keep giving.

Our resident DNA experts would be happy to help you analyze and make sense of the results you get from any of the major DNA testing companies. Get started by requesting a free quote today.

Filed Under: Adoption & Genetic Genealogy Tagged With: DNA, genetic genealogy, genetic testing

About the Author

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Paul - Legacy Tree Genealogists Researcher
From a young age, Paul Woodbury fell in love with genealogy research. To pursue his passion for this field, he studied genetics and family history at Brigham Young University. To aid in his desire to share his knowledge with others, he has also received a masters degree in instructional design and educational technology from the University of Utah. Paul currently works as a DNA team lead at Legacy Tree Genealogists where he has helped to solve hundreds of genetic genealogy cases. In addition to genetic genealogy, Paul specializes in French, Spanish, and Scandinavian research and regularly presents on topics for these areas. is a graduate of Brigham Young University, where he studied genetics and family history. He specializes in genetic genealogy (DNA research), French, Spanish, Swedish and Norwegian genealogy research.

Comments

  1. Corinne Pollman says

    April 20, 2015 at 11:22 pm

    Thank you for keeping us newbies informed about whats happening in the field.

    Reply
  2. Connie Gray says

    April 21, 2015 at 12:15 am

    DNA testing is being used by adoptees to reunite with biological family. Do you take those cases as well?

    Reply
    • blankJessica - Legacy Tree Genealogists President says

      April 21, 2015 at 12:21 am

      Yes, we do and we love being able to help in that way.

      Reply
  3. Alice MacDonald Long says

    April 21, 2015 at 6:33 am

    Family Tree DNA also has a test – the “Big Y” where they test many more markers than other tests. A male cousin did this test which takes longer to get the results, but we now know much more because we have a very large surname group that all tested.

    Reply
    • blankJessica - Legacy Tree Genealogists President says

      April 21, 2015 at 9:46 pm

      Hi Alice, Great to hear that the “Big Y” was successful for you! Although this article focused on the most common and most regularly successful tests, in the future we could delve more deeply into more specific Y chromosome tests and outcomes.

      Reply
      • Ingrida says

        January 7, 2017 at 10:35 pm

        Dear Jessica, What would be your outcomes ..re;DNA ? do you have anything in mind or there are some proposed plans? thank you. Ingrida

        Reply
        • blankJessica - Legacy Tree Genealogists President says

          January 10, 2017 at 3:10 am

          Hi Ingrida! Please contact us at [email protected] and we can talk about helping you with your DNA needs.

          Reply
  4. Allison - Legacy Tree Genealogists Project Manager says

    April 21, 2015 at 6:22 pm

    Excellent essay on the basics of DNA and DNA testing. The writing was clear and easy to follow and helped make DNA understandable. As databases for DNA testing grow, it will be fascinating to watch genealogy brick walls, those that had previously been unsolvable mysteries, crumble and become resolved.

    Reply
  5. katalena smith says

    April 23, 2015 at 7:59 am

    I’m 14 and my grandmother was taken from a native american tribe when she was a baby she has always wanted to know if she has siblings can you please help being able to help my grandmother would mean the world to me. thanks

    Reply
    • blankJessica - Legacy Tree Genealogists President says

      April 27, 2015 at 12:01 am

      Hi Katalena! We would love to help. You can learn more about what we offer here: http://www.legacytree.com/ready-discover-story, then contact us with more details.

      Reply
  6. Charles M. says

    May 14, 2015 at 1:54 pm

    This is a great intro!

    I’ve added a link to this page to my website’s Resources section.

    Reply
  7. gwen lundry says

    May 16, 2015 at 12:07 pm

    who do I context to get the DNA kit and does this just go on the mothers side or fathers
    side too to fine where you come from ? and I was told American Indian also. thanks
    gwen

    Reply
    • blankJessica - Legacy Tree Genealogists President says

      May 17, 2015 at 9:33 pm

      Hi Gwen,

      You can do autosomal tests (which give information on both the mother’s and father’s sides) at AncestryDNA, 23andme, or Family Tree DNA. They will provide you with an ethnicity estimate which will give you an estimated percentage of Native American DNA.

      Reply
  8. JoBeth Halferty says

    April 30, 2017 at 11:43 am

    There are no more males in the line I am trying to research. How can I find out if I am related, the line came through my grandmother.

    Reply
    • Amber Brown says

      May 1, 2017 at 7:11 pm

      First make sure that you have exhausted research on all male descendants of the line you are attempting to research even if they may not be descended through the same line you are. If the ancestor of interest was a great grandparent, perform autosomal DNA testing for yourself. If they were a second great grandparent, find two descendants from unique descent lines to perform autosomal DNA testing. For a third great grandparent, find three and so on. If you would like a more detailed testing plan within the context of your family tree, feel free to order a DNA Analysis.

      Reply
  9. Jacqueline Koscheski says

    May 17, 2018 at 10:11 pm

    I had a bad experience with my reunion. At this point, all I want to know is am I french, Irish or German! I did the Helix and it was a joke! Nothing about what I want to know and after many requests via email, they still will not clarify the results with me! Without spending a small fortune, what can I do?

    Reply
    • Amber - Legacy Tree Genealogists says

      May 17, 2018 at 11:40 pm

      We would be happy to assist you! Please submit a consultation request form here, and a member of our team will contact you to discuss the specifics of your research goals.

      Reply
  10. Dianne Level says

    November 26, 2018 at 12:37 pm

    I have 3 living sons. Their father is deceased and all other relatives except for their aunt (my husband’s sister). We have been trying to research my husband’s line but keep hitting a brick wall before his grandfather who migrated to Ohio from Virginia on foot at at he age of 12. What type of DNA test can we have done that may give us some answers.

    Reply
  11. Terri Lucas says

    March 26, 2019 at 3:04 pm

    Sisters and I took an ancestry test and when we got the results it seems that the older sister is not considered a close relative. She won’t let me pursue it but I’m so curious I’m wondering if I have any direction to go without having her results and no family history to go on.

    Reply
    • Amber - Legacy Tree Genealogists says

      March 27, 2019 at 8:59 am

      Surprises in our DNA results can be unsettling. While it is possible to conduct additional research to help find answers, we suggest you and your sister take some time to process the findings. Perhaps in time she will be willing to reconsider her current stance. We’ve put together a list of resources that can help individuals when they receive unexpected DNA test results. Good luck to you both!

      Reply

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