I was recently (well a few months ago at least) lucky enough to win a competition held by The Environment Institute at the University of Adelaide. The prize? A Genographic Kit from National Geographic.
What the hell is that? I hear you ask. Well I didn’t really know either when I won, I tend to just enter competitions impulsively, but after looking into it I’m glad I did and given this is my first post here at SciAm I figured it might introduce me a little further. My first post might not be about disease but I promise this will be a rare occurrence.
The Genographic Project (in its own words) “is seeking to chart new knowledge about the migratory history of the human species by using sophisticated laboratory and computer analysis of DNA contributed by hundreds of thousands of people from around the world”. Pretty cool huh.
So I received my unassuming little kit, followed the instructions and took two samples and sent them off.
Then I received my results. And a certificate.
The DNA that was sequenced was my mitochondrial DNA, which allows me to follow my maternal heritage backwards through time. Mitochondria, the energy factories within cells are only ever inherited from your mother in the egg that eventually becomes you after your father adds his genetic payload. Mitochondrial DNA sequencing is very common practice and probably the best way to track an evolutionary history.
My results indicate, first off, that I am part of Haplogroup H, the most common western European haplogroup. Not so surprising, as I know both sides of my family come from Ireland and Scotland, but using the mitochondrial sequence I can follow back my maternal lineage to the Mitochondrial Eve.
Mitochondrial Eve is the nickname given to the most ancient mitochondrial sequence which is consequently is also the common sequence to which all people on Earth can trace their maternal heritage back to. Mitochondrial Eve lived between 150,000 and 170,000 years ago in East Africa. Though humans have been around for about 200,000 years all other lineages of mitochondrial DNA died out and now only descendants of Eve remain.
From Eve, my lineage became part of the L haplogroup and specifically the L1 group. The L haplogroups represent the earliest divergence of mitochondrial Eve’s descendants. Eve’s descendants split into the L0 and L1 groups. Both these groups persist in Africa to this day predominantly in groups that live in hunter-gatherer groups and maintain a very traditionally African way of life but my L haplotype diverged further. From L1 another split produced the L2 haplogroup, which appeared to split and head west into more central Africa.
The L2 haplogroup now is very prevalent along the west coast of Africa but another quick split saw my maternal descendant diverge again and head north, out of Africa as part of the L3 haplogroup.
The L3 haplogroup originated approximately 80,000 yeas ago and represent the first group of modern humans to leave Africa. Leaving Africa was a big shift. It coincided with a change in climate that allowed the grazing animals hunted by my ancestors to migrate north across the Saharan gateway into southwest Asia and they followed. After making it to Asia the L3 haplogroup gave rise to a large portion of the Middle Eastern population but also further divergences such the next one in my lineage, the divergence to haplogroup N.
Haplogroup N continued their migration north into west Asia and the eastern Mediterranean, may have overlapped the Neanderthals that had preceded their migration, and eventually underwent a large number of divergences which predominate global populations. My lineage follows on from N to R.
N and R haplogroups actually stayed together and appear to have maintained close contact in what is now modern Turkey but R haplogroups also spread back to Africa as well as into what is now southern Russia. Eventually a divergent lineage of the R haplogroup, known as the pre-HV haplogroup also developed alongside N and R haplogroups. This makes the ‘near east’ a cradle of a number of haplogroups. It follows that these groups slowly spread to populate central and southern Asia as well as moving west into modern Europe.
The pre-HV haplogroup diverged again into the HV haplogroup, which certainly ran into the Neanderthals living throughout Europe. Competition for resources would have been fierce but modern humans could communicate easier, had better weapons and importantly the brains to exploit the Neanderthals and the environment, a combination that proved impossible for the Neanderthals to withstand.
The HV haplogroup broke further and my lineage continues into the H haplogroup which pushed for the west European coast and on the way spread the tools of agriculture but the onset of a cold snap approximately 20,000 years ago changed the genetic landscape of humans in Europe pushing them toward the equator again into Italy among other places to wait out the cold.
15,000 years ago the cold retreated and the H haplogroup populations exploded over Europe. Now between 40 and 60% of all Europeans are derived of the H haplogroup.
But that’s where my mitochondrial DNA lineage gets murky and so that’s where the analysis ends. The intention is to develop a clearer idea of more recent migrations by collecting more and more data which may tell me how my ancestors made it to Ireland as from there my maternal lineage is known. My ancestors come from Limerick before my grandmother emigrated to England and my mother from England to Australia as a child.
This Genographic Project is a monumental undertaking but the information is startling and wonderful. To be able to follow my lineage back 200,000 years is a rare and unique gift and easily the best prize I have ever won.