What are Haplogroups? And how can you use them effectively in your research?

Along with testing for ethnicity, health, and heritable traits, many of the major genetic testing companies also include haplogroup assignments with your results. Males inherit their patrilineal haplogroup through their Y-chromosome, which is passed down from their father’s father’s father etc. Males and females inherit their matrilineal haplogroup through their mtDNA, which is passed down from their mother’s mother’s mother etc. While fathers only pass down their Y-chromosome to their sons, mothers pass down their matrilineal haplogroup to all of their children. Try thinking of haplogroups as an unbroken chain that binds you, your parents, and your children from ancient times down to the present day.

Some companies like 23andMe and LivingDNA include your haplogroup assignment(s) along with your ethnicity breakdown. Other companies, like FamilytreeDNA, offer specialized testing along with access to large databases of testers where you can compare your results with others and potentially find matches. Some third-party companies, like WeGene, offer an inexpensive genetic analysis of your autosomal test results and supply you with health information along with a predicted haplogroup assignment.

From my experience answering questions about haplogroups in the various genetic genealogy Facebook groups, administrating multiple surname projects, and through my own client work, there is no other concept in genetic genealogy that creates more confusion and mis-information! So what is a haplogroup? How can you use this information more effectively in your research?

The technical definition of a haplogroup (taken from the ISOGG Wiki page is): “…a genetic population group of people who share a common ancestor on the patriline or the matriline. Haplogroups are assigned letters of the alphabet, and refinements consist of additional number and letter combinations.” (1) Another way to think about haplogroups is that they represent a shared common ancestor, and if both you and I share the same haplogroup, then we are cousins, albeit likely distant cousins. Since we don’t know our shared ancestor’s name, they are assigned alpha-numeric names upon their discovery.

The best analogy I have come up with to explain haplogroup assignments goes something like this: Imagine yourself on a very tall ladder. You are at the bottom rung, and Y-chromosome Adam or Mitochondrial Eve is at the top rung (this of course depends on which line you are testing, your patrilineal line or your matrilineal line). Some of the genetic testing companies, like 23andMe for example, only test about halfway down the ladder, which means the haplogroup assignment they give you stops short from reaching all the way down to you.

The haplogroup (or shared ancestor) 23andMe or LivingDNA assigns you likely lived 10,000 or more years ago. Other companies, like FamilytreeDNA, offer tests that (almost) cover the entire ladder, and will test for all of your haplogroups (or shared ancestors), starting with Genetic Adam or Eve and ending with you. The people who you share your most recent haplogroups with can be very useful in your research, especially since FamilytreeDNA maintains a database where you can contact your close matches and look at their family trees.

The other fascinating thing about haplogroups is that they can be roughly dated to a specific period of time and geographic region, which means that under the right circumstances you can assign haplogroups to known historical figures. A simple analogy of the dating calculation goes something like this: For Y-DNA testers (ie. males), every rung of the ladder is a new descendant haplogroup (or shared ancestor), who descends from the haplogroup (or shared ancestor) above them. If you test via a Next Generation Sequencing test like the Big Y-700 at FTDNA, the distance between rungs can be dated somewhere between eighty-two to one hundred and thirty-one years or so. (2)

For mtDNA haplogroups, mutations happen much more infrequently, and every rung may represent several thousand years or more. While not quite as useful, it can offer very important information, especially when little to nothing is known about that line. And the best part about haplogroup testing is that every person has one (or two if you are male). Along with yourself, testing siblings, parents, grandparents, cousins, aunts, and uncles will give you the haplogroup information for several of your genealogical lines, not just your own patrilineal or matrilineal line.

So what can you do with this information? If you are trying to test a hypothesis that the descendants of two potentially related lines are possibly related, you can test a living descendant from each line to see if they match each other. You can do this by comparing more ancient haplogroups at 23andMe or LivingDNA, or with more recent haplogroups through NGS testing at FamilytreeDNA. If you are looking for unknown genealogically relevant matches that may have already tested, then NGS testing at FamilytreeDNA is the way to go, hands down.

A few examples from my own experience:

Last year I had a breakthrough researching my patrilineal line thanks to a clue I discovered through my father’s autosomal matches, which led me to potentially identify my third great-grandfather’s birth parents back in the old country. In order to test this theory, I needed to identify and locate a living male descendant from a different branch of this same patrilineal line who would be willing to test. Fortunately, I was able to track one down and thankfully, he was willing to take a Y-DNA test at FamilytreeDNA. The results came back that we were a close match, and the paper trail was confirmed!

My matrilineal line ends with my 5th Great-Grandmother, Rebecca Hays, who I practically know nothing about. The only record I have located that mentions her name is her daughter’s death certificate. I don’t know when or where she was born, who her parents were, or when and where she died. Thanks to the Full Sequence mtDNA test at FamilytreeDNA, I now know that her matrilineal haplogroup was I4a, that she was most likely British, and I now have thirteen close matches with whom to compare my family tree with! That is a lot more information to work with than what I had before, which was just her name.

While haplogroup testing won’t solve every family riddle or break through every brick wall in your tree, it can definitely help you in your research, but only if you understand how it works. If the pursuit of genealogy is to discover your ancestors and learn more about their lives, then why stop when the paper trail runs out? Just because we don’t know their given names doesn’t stop us from being able to identify them through genetic testing. So what’s stopping you from learning about your paternal or maternal halpotype?

(1) ISOGG, ”Haplogroup,” ISOGG Wiki (https://isogg.org/wiki/Haplogroup : accessed 22 Aug 2019).

(2) Y-DNA Warehouse, “Next Generation Sequencing Statistics” (https://ydna-warehouse.org/statistics.html : accessed 22 Aug 2019).