Haplogroup L7 is the newest mtDNA haplogroup! Here are some quick facts about haplogroup L7 and a reminder of what mtDNA haplogroups are all about.
Before we talk about this exciting new mtDNA haplogroup, let’s give the somewhat-neglected mtDNA a little love.
Did you know that mtDNA is responsible for launching us into this age of genetic genealogy?
It was mtDNA and its direct maternal inheritance pattern that first struck population geneticists as a valuable asset in telling the stories of ancient and modern humanity. Not only that, but this was history told from a woman’s point of view (which we know is very rare).
But recently, mtDNA has also been a good reminder of just how new this technology is, and just how much we still have to learn. A groundbreaking paper published this month in Nature by Meir et al (the “et al” includes my friend Roberta Estes! Way to go, Roberta!) reports a new lineage has been added to the mtDNA world tree: the L7 haplogroup.
Now let’s back up for just a second and talk about the mtDNA world tree. Just like your family tree, the mtDNA tree has roots and branches, each with its own particular place and time. Perhaps in your family the Hardingers are the ones from Maine between 1770 and 1890 and your Bristows are the ones from Louisiana between 1819 and 1910.
The mtDNA branches are similar, but in vastly expanded timeframes and geography. Each branch is called a haplogroup. Haplogroups H, J, and K, for example, are associated with European populations, while haplogroup L represents the earliest, African lineages.
But just as in your tree, there is still a hierarchy. There are still children and grandchildren, but again, instead of the 25-30 year generations that you see in your tree, the mtDNA tree boasts more like thousands or tens of thousands of years per generation. We see this hierarchy in the naming system of mtDNA. They use an alternating letter-number system that lets us know everyone’s relationships to the major branches.
So a lineage might be named H3a3b2d or L4c5d1. Each letter or number represents one mutation, or a group of mutations that mark a branch point in the lineage.
In general, it was thought that all the founding mothers of the tree had already been identified after 40 years of mtDNA research. Well, that’s not true exactly. We know that only about a quarter of all the mtDNA lineages that were once present on earth have made it all the way to 2022. But we had thought we had found all the early linages that still exist.
Thankfully, we were wrong.
L7 haplogroup joins the mtDNA world tree
Previously, there were six main African lineages from which all other lineages descended. They were conveniently named L1-L6. Now there’s another: L7.
Just to be clear, new branches are added to the mtDNA tree fairly often. But they are added much much further down the tree – more like adding twigs to branches. But this? This is creating an entire new limb!
Quick facts about mtDNA haplogroup L7:
- L7 is 100,000 years old: one of the oldest lineages known
- L7 has been carved out of L5 (it includes some DNA sequences formerly attributed to L5)
- L7 already has its own sub-branches: L7a, L7a1, L7b1 and L7b2
- Some of those sub-branches divide even further, for a total of 13 sublineages in L7
- To date, only 19 people in the world have been assigned to L7 (among the hundreds of thousands who have tested their mtDNA)
- Also, a 16,000 year-old DNA sample from Malawi has been identified as L7
- L7 has the highest occurrence so far in modern-day Tanzania (a neighbor of Malawi), with higher rates also seen in neighboring Kenya, Ethiopia, Sudan and South Sudan
This is such an exciting time to be a genetic genealogist! And it is such a good reminder that we know so much less than we think we do about how genetics has shaped humanity, and therefore our families.
Thank you and congratulations to Roberta and the rest of her scientific team for this breakthrough.
Are you L7? Or one of the others?
You can learn your haplogroup assignments through DNA testing specific to your maternal side (mtDNA) or your paternal side (YDNA). Where do you want to go first?