Genealogical DNA testing is tremendously popular, and for good reason. Sometimes the written records just aren’t there, or are tough to find, and DNA can help fill in the gaps.
The most common DNA test for genealogy is autosomal testing, but that’s not the only type available. Mitochondrial DNA (mtDNA) testing offers different information which may be key in uncovering your past.
Let’s take a look at what mtDNA is, how it’s different, and why an mtDNA test is right for you. We’ll also look at which company’s mtDNA test has the most to offer when it comes to genealogy (spoiler alert, the best mtDNA test is from FamilyTreeDNA).
What is mitochondrial DNA testing?
DNA is found in every cell in your body. And even though the exact same DNA is found in every cell, you have more than one type of DNA. They can be tested differently, and tell you different things.
Most genealogical DNA tests look at autosomal DNA, which examines the autosomes found in the cell’s nucleus. This is passed down in roughly equal amounts from each of your parents, and is a mixture of both. Your parents’ DNA is a mixture of their parents, and so on back through time.
On the other hand, mtDNA is found outside of the nucleus, and it is much shorter and simpler. And unlike autosomal DNA, it only comes from one parent, your mother. Your mtDNA is a virtually exact copy of your mother’s, which she got directly from her mother, and so on through the generations.
Because it doesn’t get mixed in each generation, mtDNA changes very, very slowly over time. Even slower than Y-DNA. That means it can be used to trace your direct material line back for thousands of years.
What makes testing mtDNA different?
Testing mtDNA works basically the same as testing autosomal DNA, except it deals with a much smaller piece. Autosomal DNA has around 3.2 billion base pairs, while mtDNA has only 16,569 base pairs on average. That makes it a lot easier to spot the tiniest changes.
In theory, mtDNA is passed down as a perfect copy through each generation. In fact, it could remain exactly the same for dozens of generations. But over long enough periods of time, minor changes take place. The more differences between two peoples’ mtDNA, the further back they are related.
Calculations made in 2013 based on estimated mtDNA mutation rates claim that every living person on Earth can trace their ancestry back to a single common ancestor who lived about 150,000 years ago, the so-called “Mitochondrial Eve.”
Boys have mothers, too
Even though mtDNA is passed down purely from women, it is passed on to all of a woman’s children, including her sons. Brothers and sisters both share the same mtDNA passed on from their mother, and both males and females can have mtDNA testing done.
However, because mtDNA is only passed on by women, an mtDNA test will not tell you anything about your male ancestors. It won’t even tell you anything about your female ancestors except in a direct matrilineal line: your mother, her mother, her mother’s mother, and so on.
How mtDNA testing works
Depending on the exact test you take, mtDNA testing looks at one or more of three regions:
- HVR1: a small set of base pairs at the end of the DNA strand
- HVR2: a small set of base pairs at the beginning of the DNA strand
- Coding region: the large central portion of the DNA strand
HVR stands for Hyper Variable Region, and refers to the fact that the two ends of the mtDNA tend to change more often than the center. Keep in mind that by “more often,” we’re still talking as little as once every ten, twenty, or even fifty generations.
An HVR1 or HVR2 test (or a combined HVR1/HRV2 test) will do a good job of tracing your ancestry. However, for the most accurate and useful results, look for tests that include the coding region, too. It may change more slowly, but it does change. Testing all three regions is usually called a “full sequence” test, and is your best option.
Like other DNA tests, you begin by taking a genetic sample. For FamilyTreeDNA, that involves swabbing the inside of your cheeks, though some companies may have you collect saliva in a vial instead. Once the sample is taken, sealed, and shipped off to the lab, it takes them about six to eight weeks to process it.
What does a mitochondrial DNA test show?
The main result you will receive is called a haplogroup, which is a group of people who can all trace their lineage to a common ancestor. Each major haplogroup is identified by a letter, followed by one or more numbers or letters that narrow them down into smaller groups.
Because the mitochondrial DNA is so short, a full sequence test can look at every single base pair, identifying your haplogroup with almost perfect accuracy.
Important! Both mtDNA and Y-DNA tests will provide a haplogroup result, but they are not the same. In some cases, the two tests even use the same labels (such as K2), but they mean completely different groups of people. If you get both tests done, be sure not to get the two results confused.
Your mtDNA test will also give you a list of matches. Unlike Y-DNA, this list isn’t particularly useful for genealogy. That’s because even an exact match can be hundreds of years to the common ancestor and beyond the genealogical paper trail.
How mtDNA tests help
On the surface, mtDNA tests may seem limited. After all, it only traces one single line of ancestry. But it tells you a lot.
Mitochondrial DNA testing lets you peer into the distant past. Compared to an autosomal DNA test, which can take you back a couple hundred years, mtDNA takes you back thousands of years. Think you ancestors have always been Scottish? Your mtDNA results may reveal they were Scandinavian invaders who settled in Scotland a thousand years ago.
Anywhere records are scarce or missing, mtDNA testing can provide you with clues. For those with Native American ancestors, this can be especially important. Native American haplogroups are very distinct from most others. If your mtDNA haplogroup matches those historically found in North or South America, you can be confident that you have some Native American ancestry, even if you haven’t found the written records to prove it.
Mitochondrial DNA testing for genealogy
If you get your testing done by a company dedicated to genealogy, such as FamilyTreeDNA, you will have the option of sharing your results with other researchers, and you’ll be able to see which of them have matching results. That can be a tremendous help when it comes to finding distant cousins. And because they cared enough about genealogy to get tested, there’s a good chance they will have research that can quickly grow your family tree.
FamilyTreeDNA also has a variety of projects, including haplogroup projects. These let you directly connect with other interested researchers and share information and resources. Most haplogroup projects also try to create maps to trace their ancestors through time.
Who does mtDNA testing?
FamilyTreeDNA will likely be your best choice when it comes to genealogical mtDNA testing. Their test is affordable (currently $139), and because their primary focus is on genealogy, they will provide you with the best resources to connect your DNA with your family tree.
23andMe’s autosomal DNA test does include your mtDNA haplogroup, but there are two things to consider. First, they identify only major haplogroups, while FamilyTreeDNA breaks it down into the smallest subgroup possible. That extra level of detail can mean a lot. Second, FamilyTreeDNA’s greater focus on traditional genealogical research makes it easier to connect your results to specific ancestors.
Ancestry.com is great for many things, but they don’t offer mtDNA testing at all.
mtDNA testing for adoptees
Many adoptees now turn to DNA testing to find their birth parents, but mtDNA can’t be used to prove maternity. Keep in mind that you may have an exact mitochondrial match with thousands, or even millions, of people. An exact match does not prove you are mother and child, only that you have a common ancestor sometime in the past couple thousand years.
On the other hand, if the mtDNA results don’t match, that can be used to disprove maternity. While a tiny difference might be possible between mother and child, there is no possible way they don’t match.
The only reliable test for maternity (or paternity) is an autosomal DNA test.
No studying required
An mtDNA test is one of the easiest tests you’ve ever taken. Just follow the instructions in the kit, and you’ll get a perfect result every time.
Discovering your maternal haplogroup can open up a world of possibilities. It helps you trace your ethnicity, determine where your ancestors likely lived over time, and can connect you with other genealogists and family historians tracing the same ancestral lines.
No matter where you are in your family search, you can benefit from an mtDNA test. And when it comes to mtDNA testing, your best bet is FamilyTreeDNA. Order your kit today, and start digging up your ancient maternal roots.