By: Katy Rowe
Learn how mtDNA testing can uncover connections between testers who share a common matrilineal ancestor, regardless of where the records stop. Explore the benefits of mtDNA testing for tracing your direct maternal line and breaking down genealogical brick walls.
Are you struggling to make progress on your genealogy research? Have you hit a brick wall in tracing your family tree? Using mitochondrial DNA (mtDNA) testing may be the breakthrough you need.
By unlocking new avenues of research, mtDNA testing allows you to trace your direct maternal line and connect with others who share a matrilineal ancestor. Even if records are scarce or non-existent, mtDNA testing can help you break down genealogical brick walls and uncover new connections to your family history.
What is mitochondrial DNA?
Mitochondrial DNA (mtDNA) is found in most human cells inside the mitochondria but outside the cell nucleus. This type of DNA is inherited exclusively from your mother.
Because of its unique inheritance, mtDNA allows you to trace your direct maternal line through your mother, your grandmother, your great-grandmother, and so on.
mtDNA testing allows you to trace back to Mitochondrial DNA “Eve.” Eve lived about 150,000 years ago and is the matrilineal ancestor of all humans.
Due to its far reach, with mtDNA, you can discover matches who share a common matrilineal ancestor with you beyond the typical 5-6 generation time frame of autosomal DNA tests and, in turn, break more brick walls.
X-DNA vs. mtDNA
While the two are often confused, mtDNA and DNA from the X chromosome (X-DNA) are completely different. The X chromosome is found inside the cell nucleus, along with the other autosomal chromosomes (1-22) and the male Y chromosome.
Women inherit a randomly recombined X chromosome from their mother and a non-recombined X chromosome from their father. Men inherit a randomly recombined X chromosome from their mother and a Y chromosome from their father.
While X-DNA can be used to determine a shared common ancestor with other autosomal matches, it does not follow an exclusively matrilineal inheritance path, and due to random recombination, it can only reach back about 5-6 generations, similar to autosomal DNA.
Why does mtDNA only come from my mother?
Males do have mitochondria, but they only inherit them from their mother and cannot pass them on to their offspring. This is because when a fertilized egg is formed, the egg cell contributes the majority of the mitochondria that will be present in the resulting embryo, while the sperm cell contributes very few.
During fertilization, the sperm cell’s mitochondria are usually destroyed or left behind in the tail of the sperm, while the egg cell’s mitochondria go on to replicate and populate the cells of the developing embryo. As a result, all of the mitochondria in an individual’s body are ultimately derived from their mother’s egg cell.
This is why mtDNA is passed down exclusively through the maternal line and why it can be used to trace an individual’s direct maternal ancestry.
Understanding Your Complete mtDNA Haplogroup
While many autosomal DNA testing chips include enough mtDNA SNPs on them to provide you with a basic haplogroup, there’s so much more that comes with a strictly mitochondrial test like the mtFull Sequence.
Let’s stick with haplogroups for a minute. Sure, some autosomal DNA tests will provide you with a basic mtDNA haplogroup, but you’ll only receive your complete mtDNA haplogroup from a full sequence mtDNA test. What’s the difference? With a basic mtDNA haplogroup, you’re only getting part of the story.
Think of your haplogroup like an address. You have the root of the haplogroup (H, V, U, J, L, etc.). This tells you what country the address is in. With an autosomal test, that might be as specific as you get.
Past the root, haplogroups are divided into branches notated by alternating numbers and letters. With a mtFull Sequence test, your haplogroup won’t be just a root, like H, but instead, it could be H2a1a1. That’s a mouthful, but it gives you so much more information on your maternal story! Let’s think about the address again. If H is the country, then 2 is the state. The first a is the county, the first 1 is the city, the next a is the street, and the last 1 is the house number.
While your haplogroup migration path won’t be as specific as a city or a street, your full haplogroup can tell you the regions your matrilineal ancestors migrated from and to, if they were Native American, Jewish, or part of another cultural group, and by comparing with the self-reported Earliest Known Maternal Ancestor locations of other testers, the country your ancestors may be from.
Finding Useful mtDNA Matches
The other major benefit of mtDNA testing is that you receive mtDNA matches that share a common ancestor with you on your matrilineal line. While you can get a basic mtDNA haplogroup with some autosomal tests, you only receive autosomal matches with those tests, not mtDNA matches.
When it comes to traditional genealogy research about the women in your family tree, it’s easy to get stuck. Most societies were patriarchal and not matriarchal, and there are far more records pertaining to the men in our family trees than the women. Women’s names were changed with marriage, and you may not be able to find their birth surnames. In some cases, the mother’s name isn’t even recorded on birth certificates!
Matching with mtDNA testing uncovers connections between testers who share a common matrilineal ancestor, regardless of where the records stop. The test level you match at and the genetic distance, or the number of mtDNA mutation differences, between you and the match can help determine when you share that common matrilineal ancestry.
Genetic distance in mtDNA is limited right now but keep reading to find out how we plan to improve in the near future.
Tools for mtDNA Research
With the mtFull Sequence test, FamilyTreeDNA provides you not just a list of matches that share a common matrilineal ancestor with you, but also tools to discover who that ancestor is, expand your family tree, confirm family stories and legends, and break brick walls.
On your Matches list, you’ll be able to view your matches’ family trees, their Earliest Known Maternal Ancestors (EKMA), and those ancestors’ locations. While you may not recognize the names of your matches, their family trees are the first thing you should check to find a connection.
FamilyTreeDNA offers both a Family View and Pedigree View for family trees. mtDNA is passed down matrilineally (mother, mother, mother, etc.), so the Pedigree View is going to be helpful here since you can easily follow that direct maternal line. Look for ancestors you recognize on that direct maternal line.
You’ll also want to check out your matches’ EKMA locations. You can do both on the Matches page (there’s a column for this information for each match) and on the Matches Map.
The Matches Map plots your matches’ EKMA locations on a map and is divided by the different test levels and color-coded by genetic distance.
Personally, I can only trace my direct maternal line back to Paducah, Kentucky, prior to the Civil War. However, my matches on the Matches Map have their EKMA locations in Ireland and Scotland.
Finding the connection between Kentucky and Ireland or Scotland may be difficult. But when I look back at my Matches list, I notice there are several other matches that entered the EKMA name and dates but not a location. This is why they are not showing up on the Matches Map, but I still have options. I can determine those ancestors’ locations through my matches’ family trees or by emailing them and asking.
By contacting my matches and asking for specific information about their EKMA, I could also learn more from those matches about my direct maternal line.
Make sure you’re filling out your Earliest Known Ancestor names and locations as well as your Family Tree as best you can!
For more about how to use these mtDNA tools to break brick walls, including success stories, check out this great presentation by genetic genealogist and Millon Mito Project team member Roberta Estes from Rootstech 2022.
The Benefits of Testing Outside Your Direct Maternal Line
Maybe your brick wall isn’t on your direct maternal line. Maybe it’s on your father’s mother’s direct maternal line, or maybe you don’t know your maternal grandfather’s mother. Taking an mtDNA test yourself will only provide matches on your matrilineal line (your mother, her mother, her mother, etc.).
You can find other people in your family tree who descend matrilineally on the line where your brick wall is and get them to take the mtFull Sequence test and help you find the answers.
Check out this presentation by Group Projects Manager Janine Cloud from Rootstech 2023 to learn how she confirmed her third great-grandmother’s matrilineal line was Native American by testing her cousin’s mtDNA.
The Million Mito Project will revolutionize mtDNA testing and tools.
The Million Mito Project was launched in 2020 as a collaborative effort between FamilyTreeDNA’s Research and Development Team and the scientific portion of the Genographic Project.
The current mtDNA haplotree is Phylotree version 17, which was built with a little over 24,000 academic and privately submitted samples, some of which only had partial mtDNA results. The last update was in 2016, and there are no plans to update again.
The goal of the Million Mito Project is to pick up where the Phylotree left us in 2016, analyze more mtDNA sequences, and reimagine the mtDNA haplotree, or Mitotree. By examining more mtDNA data and applying the processes that allowed FamilyTreeDNA to build the world’s largest Y-DNA haplotree—the Tree of Mankind—we can also create the world’s largest Tree of Womankind.
For an in-depth look into this research, check out this great presentation from FamilyTreeDNA’s population geneticist, Dr. Paul Maier, from Rootstech 2022. For less science-focused information on the Million Mito Project, this presentation by Janine Cloud has you covered.
Most, if not all, of the haplogroups and branches from the Phylotree are very old; the Time to Most Recent Common Ancestor (TMRCA) for the branch is estimated at thousands of years ago. Just matching someone with the same haplogroup as you is not helpful for determining when your genealogical common ancestor was or who they were (although other mtDNA tools can help).
The Million Mito Project is building the Mitotree by using new sequence data—20 times more data than the Phylotree used. That data will create new branches and, most importantly, younger branches.
The more refined branching on the new Mitotree will be able to provide you with a better TMRCA with your mtDNA matches, with many estimated within a genealogical timeframe.
We can look at this example of haplogroup U5a2b2a. On the left, the “before” image is from the Phylotree. With the Phylotree, there’s barely any definition downstream of this branch, which is estimated to be 5000 years old.
The “after” image on the right is from the Million Mito Project’s research. Analysis of all the additional sequences at U5a2b2a today allows us to refine this branch further into new subclades with a TMRCA estimated between 2500 and as close as 500 years ago.
The Future of mtDNA Research
Additional sequencing—meaning more testers with mtFull Sequence results—will allow us to refine these subclades and the TMRCA even further, like we already do today for the Y-DNA haplotree.
This means more matches for everyone, better TMRCA estimates between you and your matches, and improved tools like an mtDNA version of Discover™, making it even easier to break those brick walls!
If you haven’t taken our mtFull Sequence test yet, get it today and get a head start on breaking brick walls before more updates are available within the next year.
About the Author
Katy Rowe
Product Manager at FamilyTreeDNA
Katy Rowe has always been interested in genealogy, inspired by her maternal grandparents, who told her stories about their family and family history when she was little. After studying anthropology and history in college, she joined FamilyTreeDNA in 2015 and became the Trainer for Customer Support. Katy created and improved training processes and was fundamental in the creation of the Big Y Specialist team. In September 2021, she became Product Manager and has focused closely on improving FTDNA’s genetic genealogy products.