I obtain f3(French; Sardinian, Burusho) = -0.002652 (Z=-13.541) on the basis of 446,917 SNPs. This is the strongest signal of admixture in the French that involves a population that is high on the "West_Asian" component whose influence I have been investigating.
I thus carried out rolloff analysis using the French as a target population and the Sardinians and Burusho as reference populations. The exponential fit can be seen below:
The jackknife gives 239.556 +/- 50.553 generations for this admixture, which corresponds (assuming a generation length of 29 years) to 6,950 +/- 1,470 years.
Analysis of autosomal DNA from the Tyrolean Iceman and a Neolithic TRB farmer from Sweden have revealed an absence of the West Asian ancestral component and a Sardinian-like Neolithic population c. 5ka in Europe. This population may have extended to at least to the Balkans in space and down to the Iron Age in time.
In my opinion, the simplest explanaton for the evidence is that the admixture picked up by rolloff took place in West Asia itself c. 7ka, and then this population begun its movement into Europe at some post-5ka time period.
Importantly, the K=12 Caucasus component appears as a mixture of the K=7 West_Asian and Southern components. The former (West_Asian) is the most important one in the Burusho, and the latter (Southern) is the most important one in Sardinians.
European Neolithic farmers, of presumably West Asian origin only possessed Y-haplogroup G2a out of the wide variety of haplogroups found in West Asia today. They also lacked the West_Asian component which is modal in West Asia today. There is also physical anthropological evidence from Greece and Anatolia, for an introduction of new population elements during the Bronze Age.
These facts combine to make me believe that there were population movements across West Asia which preceded the Indo-European invasion of Europe during late pre-history. That event is then best seen as an extension of a broader Eurasian phenomenon that affected substantially both the western parts of Asia and Europe.
Taking all the evidence into account, I hypothesize that:
- a "Southern"/"Atlantic_Med"/Sardinian-like population substratum existed in West Asia, and this spawned the early European Neolithic.
- a new "West_Asian"/Burusho-like population arrived from the east, perhaps associated with the Halaf/Hassuna cultures, or from some other unknown center of dispersal in the Transcaucasus or Iran. Mobility may have been encouraged post-8.2 kiloyear event.
- these two elements began mixing ~7 thousand years ago in West Asia
- the admixed population expanded at some post-5ka period into Western Europe.
(Obviously, more rolloff analyses are needed to study these ideas; the current one took about ~3 days, which was a little faster than I expected.)
Related (?): Is Burushaski Indo-European?
Image credit: Don Perrault (source)