It has been known for a long time that the Caucasus must have hosted many (at least partially) isolated populations, probably helped by geographical boundaries, setting it apart from open Eurasian areas.
David Reich writes in his book the following about India:
The genetic data told a clear story. Around a third of Indian groups experienced population bottlenecks as strong or stronger than the ones that occurred among Finns or Ashkenazi Jews. We later confirmed this finding in an even larger dataset that we collected working with Thangaraj: genetic data from more than 250 jati groups spread throughout India (…)
… Read the rest “Dzudzuana, Sidelkino, and the Caucasus contribution to the Pontic-Caspian steppe”
Preprint Paleolithic DNA from the Caucasus reveals core of West Eurasian ancestry, by Lazaridis et al. bioRxiv (2018).
We analyzed teeth from two individuals 63 recovered from Dzudzuana Cave, Southern Caucasus, from an archaeological layer previously dated to ~27-24kya (…). Both individuals had mitochondrial DNA sequences (U6 and N) that are consistent with deriving from lineages that are rare in the Caucasus or Europe today. The two individuals were genetically similar to each other, consistent with belonging to the same population and we thus analyze them jointly.
(…) our results prove that the European affinity of
… Read the rest “Palaeolithic Caucasus samples reveal the most important component of West Eurasians”
Some interesting excerpts from Wang et al. (2018):
An interesting observation is that steppe zone individuals directly north of the Caucasus (Eneolithic Samara and Eneolithic steppe) had initially not received any gene flow from Anatolian farmers. Instead, the ancestry profile in Eneolithic steppe individuals shows an even mixture of EHG and CHG ancestry, which argues for an effective cultural and genetic border between the contemporaneous Eneolithic populations in the North Caucasus, notably Steppe and Caucasus. Due to the temporal limitations of our dataset, we currently cannot determine whether this ancestry is stemming from an existing natural genetic
… Read the rest “Steppe and Caucasus Eneolithic: the new keystones of the EHG-CHG-ANE ancestry in steppe groups”