DNA Testing for Genealogy – Getting Started, Part Two

Posted July 25, 2012 by Geni | 10 Comments

We’re excited to bring to you part 2 of  YourGeneticGenealogist.com blogger CeCe Moore’s DNA Testing for Genealogy series. For the next few weeks, she’ll be providing a great overview about DNA testing for genealogy. Enjoy!

Last week we discussed the Y-DNA test that only traces your direct paternal line back in time, but there’s good news for you women who felt left out. Did you know that there is also a DNA test that traces your direct maternal line back in time?  It is called a mitochondrial DNA (mtDNA) test.

 

Illustrating the path of Y-DNA in blue and mtDNA in red (credit: Angela Cone)

Mothers pass mtDNA to their children, both sons and daughters, but only females pass it on. Your mtDNA was inherited from your mother and from her mother and from her mother. No matter how far back in time you go, you only have one direct maternal ancestor in each generation and she is the one responsible for passing you your mtDNA.  Your mtDNA has followed this matrilineal path down through the generations for many thousands of years intact and virtually unchanged.

Mitochondrial DNA testing is a great tool for discovering more about the females in your family tree.  As all dedicated genealogists have undoubtedly experienced, female ancestors are frustratingly difficult to trace because of the fact that they traditionally change their surname with marriage.  So, for many of us, anything that may shed light on our female ancestors’ origins is welcome.  The value of mtDNA testing is in the simple fact that if two people share an exact mtDNA sequence, then those two people descend from a common female ancestor somewhere in the past. For each individual, your mtDNA will only reflect that of your direct maternal line, however following the same rule applied to Y-DNA, any female ancestor of interest can be followed down the tree to the present day in an attempt to find an appropriate direct maternal descendant for mtDNA testing.  For example, my third great grandmother Sarah’s origins are unknown. In order to gain more insight into her ancestry, I ordered a mtDNA test for my mother’s first cousin who is matrilineally descended from Sarah.

Without getting bogged down in technical details, there are two important aspects of mtDNA results for the genealogist just venturing into genetic genealogy. The first is the match list.

Matches

Upon completion of your test, you will receive a list of matches. Only exact mtDNA matches are relevant for genealogical purposes and the higher the resolution of the test, the better. (I suggest testing at least HVR1 and HVR2, called “mtDNA Plus” at Family Tree DNA.) The surnames on your list will likely all be different since they are not retained through female lines. The goal is to determine your shared ancestor with these matches. However, because mtDNA changes (mutates) very slowly and can be passed down virtually unchanged for thousands of years, your mtDNA may be identical to that of your very distant direct maternal ancestors. For this reason, it is often impossible to find the genealogical link to your matches. For example, I have an exact mtDNA match with whom I have compared direct maternal pedigrees back to the 1500’s without finding our common ancestor.

One unexpected side benefit of mtDNA testing for me is the personal connection that I have gained to my direct maternal ancestors’ homeland. In an attempt to discover our shared roots, my Finnish match mentioned above generously extended my direct maternal line back for many generations using the local parish records in Finland. These records are not online and I might not have ever had the opportunity to examine them in person. Although we never did find our shared ancestor, we have enjoyed a wonderful friendship and I feel a much more personal connection to my Finnish roots.

Haplogroups

Mitochondrial DNA can offer us a fascinating glimpse into the ancient origins and migratory patterns of our ancestors.  When you take a mtDNA test, the testing company will not only give you a match list, they will identify your haplogroup. Simply put, your haplogroup will be a letter assignment that groups you with those with whom you share the most similar mtDNA. Since certain haplogroups originated  in specific geographic regions, it is sometimes possible to extrapolate valuable information from these assignments that is genealogically relevant. For example, my haplogroup subclade appears to be found exclusively in those who matrilineally descend from Finnish women. In my case, I already had knowledge of my Finnish direct maternal line, but one of my matches was brick walled in Colonial America in the early 1700’s, so this was very illuminating for her family.

 Geographic origins and migration patterns of mtDNA haplogroups

If you decide to take a mtDNA test for genealogy, let me suggest that you go into it with patience and tempered expectations. Identifying a common ancestor with your matches may prove to be impossible since your connection may be before genealogical time. Additionally, even though mtDNA mutates slowly, your individual signature may still be quite unique. Therefore it is not unusual to have zero exact matches in the database simply because only a small percentage of the population has tested thus far. Time will, undoubtedly, bring more matches as increasing numbers of people become interested in testing.

Although much can be learned from our mitochondrial DNA and my own mtDNA testing experiences have been very positive, it is not my first choice for the female genealogist wanting to take her first DNA test.  Join me next week for a discussion on my personal favorite type of DNA testing for genealogy – autosomal DNA.

(Update: Read part 3 here).

CeCe Moore is a professional genetic genealogist and writes the popular blog Your Genetic Genealogist. She is the Southern California Regional Coordinator for the International Society of Genetic Genealogy and the administrator of the organization’s DNA Newbie Yahoo Group. CeCe serves as an “Ancestry Ambassador” to 23andMe and on the advisory board of the Mixed Roots Foundation and is a member of Mensa. Her favorite genetic experiment is her seven-year old son, Nicolas.

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  • Mkdarlal

    Thank you for this great information.  I am looking forward to more.  My interest in this is not so much for geneology purposes but for finding out what my ancestry is.  I am adopted and have been told that the adoption agency falsified records, made up birth dates and blood lines.  I have been told I’m from an American Indian background so I’m hoping to find out soon if that is true and hopefully find out what tribe.

    • CeCe Moore

      @Mkdarlal – You should join the AdoptionDNA Yahoo Group. There are some great search angels, adoptees, birth parents and others working together to use DNA to discover the biological families of adoptees who cannot find their roots any other way. I hope you continued to read this series to determine which DNA test would be best for you.

    • ALi

      let us know what you found?

    • soconfused

      adopted here too and hoping for the same. Good luck!!!

  • Enokh

    I also have a Finnish mtDNA connection who swears that there is a connection although I cannot see it. On paper I have some very remote Finnish connections. The only perfect match I have is to my brother. Though impossible, of several hundred mtDNA connections it would be nice to be able to slide each one into a time slot. Also it would be helpful if women would universally make use of their maiden surname, and if DNA companies would do a better job of suggesting that to women. I have run into cases where women think it is OK to put adoptees in trees without clarification. It is always wise to ask everyone — did you take the test, and if a woman, did you use your maiden name. Otherwise you may fly where the wild goose flies!  

  • Enoch Haga

    I have found the situation to be exactly as you describe. My only perfect match is my brother. In addition I have a Finnish match. I have been in contact and he swears we are related. Now I believe him! I also have very remote Finnish ancestry documented on paper — but too far back to find my adopted mother!

  • kevgood

    g/o/d/d/a/m/n/ you, geni. cease and desist from publishing the profile you posted without my consent. my ancestors were killed by hitler and his stooges. i am not interested in publishing my family history on the worldwideweb. cease and desist from compiling a personal profile based loosely on my alleged ancestry/heritage. cease and desist and/or face punitive damages. you may hide your contact information from users of your commercial product, making it difficult but not impossible to track you down, but I and my attorneys can track you down even while your site tries to hide your own contact information. – signed, extremely p/i/s/s/e/d

  • Dawn

    Ancestry.com shows my mtDNA to matches in numerous haplogroups with 0 differences which I’m not all sure these are valid results especially given that FTDNA has always had 0 matches. What would you think of these results? Thanks for your great blog!

  • Jerri Rudloff

    Great information…I see you’re a Mensan as am I…I’ve joined the Genealogy SIG and found some distant connections, but it is mostly males who enter the discussions…my autosomal has me 73% Scandinavian…My maternal G-grandparents were from Denmark but the rest are ‘English’… reading a book about the origins of the British, the author states what a high percentage of Brits are Danish in origin..so I suppose my numbers are not surprising…Looking forward to reading more of your information…Jerri in California

  • Mia

    I look forward to taking this DNA study and cross referencing this with Ancestry and 23 nd me …I am a child of Holocaust Survivors and I grew up without extended family…my parents passed early on..so, for me,,,gathering these wonderful family pieces to the puzzle will be exciting….I would love to find family……all the best…always;;;) M