3 Reasons to Test mtDNA

Diahan Southard

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Should you take an mtDNA test for genetic genealogy? Here’s a free video tutorial and 3 scenarios when mtDNA testing can help your family history.

DNA testing is becoming more and more integrated into our traditional genealogical research. Millions of people have completed some form of DNA test, and the idea that genetics can help in your genealogy is finally a commonplace notion.

However, in the wake of the widespread success of autosomal DNA testing at companies like Ancestry.com and 23andMe, the two other kinds of DNA tests are often overlooked. The Y chromosome DNA that traces a direct paternal line has gotten some attention, but the mitochondrial DNA test, or mtDNA, for direct female lines is still underutilized.

Introduction to mtDNA testing

mtDNA+Inheritance+Grapghic-01.jpg Your mtDNA is directly maternally inherited, meaning that you have the same mtDNA as your mother and all of your siblings. It is the same mtDNA as your maternal grandmother, and her mother, and so on, for ten generations or more.

Unlike autosomal DNA testing, mtDNA reliably reaches back past the fourth or fifth generation in your pedigree. But unlike YDNA tests, it doesn’t tell you how closely you are related to your mtDNA matches. So it’s a test that needs to be used strategically.

Here’s a quick video tutorial to help you better understand mtDNA testing, followed by 3 scenarios when you might want to turn to mtDNA.


3 Reasons for Taking an mtDNA test

1. Fading mtDNA line

Let’s say you have an ailing great aunt, or you yourself are one of the last remaining carriers of your mother’s mtDNA.

Having your mtDNA tested first and foremost creates a record of your direct maternal line. Just as you would obtain a birth certificate or marriage license for your ancestor to see what other important genealogical information it might contain, having a record of your mtDNA is an important part of documenting your maternal line.

2. Female ancestor with unknown ethnicity

Let’s say you have a female ancestor whose ethnicity is unknown. Perhaps you think she is Native American or African American.

Along with your mtDNA profile, which helps you make connections with others, taking an mtDNA test gives you a haplogroup, or a deep ancestral group. There are different haplogroups for different world regions and populations. Sometimes knowing your haplogroup can help either confirm or dispel a family rumor about the heritage of a particular ancestor. Though for most it will just verify what you already know, like confirming that your maternal line is from western Europe.

3. Total brick wall

Let’s say it feels like, in 1873, aliens deposited your female ancestor in Virginia! If you have tried every other avenue to discover your ancestor’s origins, and currently your best theory of her origins revolves around extraterrestrial beings, you can try mtDNA testing.

The results of the testing will provide you with a list of individuals who may share direct maternal line ancestry with you, and therefore might be related to this mystery ancestor. However, that shared ancestor could be as recent as 1873, or as distant as dates that require the postnominal “B.C.” So, it is more or less a shot in the dark. But hey, if you don’t shoot, you will definitely miss!

Next steps

In general, mtDNA testing should not be the first test you turn to when seeking out your ancestors. But it does have its place in your genealogical toolbox, especially as an option to test out a research theory, so don’t be afraid to pull it out once in awhile. You can test your mtDNA at Family Tree DNA*.

mtDNA+2nd edition.png If you decide to test, I highly recommend you also purchase my inexpensive-yet-valuable Mitochondrial DNA (mtDNA) for the Genealogist guide. It explains what this kind of test may tell you, what haplogroups really tell you, and how to understand and work with your matches, which is definitely a different experience than working with autosomal matches.

Take me to that Quick Guide!

Part of this article originally appeared at www.genealogygems.com. Revised and updated in 2019 and 2020.

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<a href="https://www.yourdnaguide.com/author/guideyourdnaguide-com" target="_self">Diahan Southard</a>

Diahan Southard

As founder and CEO of Your DNA Guide, Diahan Southard has been teaching people how to find family history answers in their DNA for several years, and she's been in the genetic genealogy field since its infancy. Diahan teaches internationally, writes for popular magazines, consults with leading testing companies, is author of Your DNA Guide–The Book, and producer of Your DNA Guide–the Academy, an online learning experience.


  1. Pam Cornwell

    Hi Diahan! It’s Pam Cornwell from summer 2021 Y-DNA class! For my birthday my kids got me a mtDNA Full Sequence test kit from FTDNA and I watched this so I could explain to them why it’s a great gift for them to have purchased for me. Love your videos and your style of thorough teaching!

    • Diahan

      So fun to hear from you Pam! So glad you are still doing the DNA!!

  2. Willie J Lenard

    My mother was kidnapped as a child and we I have exhausted all possible leads to finding her relatives. I would like to take the mtDNA exam; however, I would like to hire a counselor to assist me.

      • Mory

        How can I obtain my maternal grandfather and his mother and father and so on DNA also my paternal grandmother her mother and father and so on DNA?

        • Your DNA Guide

          Hi Mory – You should test your oldest living relatives on each line of interest! And if you are the oldest left, then you can test yourself. Also, test lots of relatives if financially possible. You all inherited pieces of your ancestors’ DNA, and by testing many different people, you can try to collect all of those pieces with a process called chromosome mapping. You can learn more about that here.

  3. joelle knopf

    To do mitochondrial DNA testing say on my grandmother’s line I have to find a female relative whose mother was from that direct female line. But if I want to find out more about my grandfather I have to find a male relative whose dad was a son of my grandfather is that right and then do YDNA is that right?

  4. Roberta

    I took an autosomal DNA test.
    Results showed I had no percent of Irish.
    However, my maternal great grandmother and grandfather were from Ireland.
    How can this be? Family matches show Irish names.
    Would an Mtdna test help?

  5. Terra

    I would like to use my mtdna results to compare my maternal grandmother’s dna to a second or third cousins dna on her paternal side because she wants to know if he was her father. Both cousins parents are dead and so are my grandparents. (I.e. my grandmother was the sister of her father.) What type of test should she take or should she have a son take test or is this not possible? My maternal grandmother would have passed mtdna to my mother and me ( I am female) my cousins mtdna would be different than mine but her paternal fathers mtdna should be the same but he is not living. The choices for testing are my second cousin or 1 of her 3 boys.. lol hope this makes sense and thank you for taking time to read..

    • Diahan Southard

      To compare mtDNA you need two people who descend in a line of only women down to the tester or match. A man receives his mtDNA from his mother but he does not pass it on, so your cousin will not have the mtDNA you are interested in. A session with one of our coaches can help you explore the options available to you.

  6. BEcky Forte

    I’m take a DNA Genealogy class right now and your short videos help me make sense of everything in a clear and concise way. Thank you!!!

  7. Ellen Schmidt

    I am adopted and I have no information about my biological parents. I have a heritage test and I guess I’m wondering if that’s the right DNA test I should take


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