Thursday, June 29, 2017

Armenia's mtDNA Gene Pool Basically Unchanged Since The Mesolithic

A new review of ancient mtDNA in the Southern Caucasus mountains region reveals that the make up of this gene pool has changed little over the last 10,000 years despite the introduction of agriculture and the appearance of multiple archaeological cultures over that time period.

On one hand, this isn't terribly surprising, since the mtDNA mix in a region tends to be more stable over long periods of time than the Y-DNA mix and autosomal genetics of the same region. On the other hand, most of Europe saw a dramatic shift in mtDNA frequencies with the arrival of the Neolithic revolution, and another in the late Neolithic/early to middle Bronze Age period when there were mass migrations from the steppe.

The Caucasus, in contrast, have not seen a major mtDNA turnover which is consistent with the perception that it is a refugium in which direct ancestors of ancient populations have more staying power than they do elsewhere.

mtDNA is inherited by children solely from their mothers, so this mtDNA continuity implies that any changes in the gene pool in the Southern Caucasus mountain region over the last 10,000 years must have derived mostly from male dominated migrations (which the Y-DNA pool of the region suggest did indeed take place on at least a few occasions in some locations).

The fact that this mtDNA pool is not dominated almost entirely by a few clades of mtDNA haplogroup U is also notable, because this clade is dominant among most hunter-gather populations of Europe during the Mesolithic, probably because these populations were derived from a small number of refuges that weathered the Last Glacial Maximum period. Apparently, the refuge from which the repopulation of Europe took place was not the one in the Caucasus.

UPDATE July 10, 2017:

Davidski identifies some serious methodological flaws that detract from this conclusion. Basically, all ancient DNA samples are lumped into one group despite the fact that the 52 samples span 8,000 years of time. He sees shifts in the gene pool in the early Bronze Age looking at the raw data.



Nirjhar007 said...

Quite remarkable isn't it?.

andrew said...

Yes. Particularly because state formation in Armenia comes late and there are lots of indications of migrations.