rolloff analysis of Lezgins as Sardinian+Burusho

I have carried out rolloff analysis of Lezgins, a Northeast Caucasian population that is of particular interest due to it being modal for the "Dagestan" component whose long-distance relationships with Western Europe and South Asia have triggered a great deal of followup investigation on my part.

The Lezgins are also interesting for other reasons: they may be one of the populations related to the Kura-Araxes culture; they possess a high frequency of Y-haplogroup R1b, so they may be related to the migration that brought this haplogroup into Europe from West Asia.

In my previous analysis of the French using the same reference populations, I speculated that their signal of admixture may involve admixture between a Sardinian-like and a West Asian population in Asia itself circa 7,000 years ago, followed by a later expansion into Europe. And, in my analysis of Lithuanians and Ukrainians, I discovered a somewhat less "old" signal of admixture involving South Asian+North European references with a mean value of 5.5-6.3ky for the various population pairs.

The exponential fit for the Lezgins can be seen below:

The admixture time estimate is 198.773 +/- 70.649 generations or 5,760 +/- 2,050 years. This is not very precise, but seems consistent with the two phenomena described above. It also seems to contrast with the much younger signal for Armenians.