Draft talk:Genetic history of West Eurasians

71.84.230.170

Just wanted to let you guys know that 71.84.230.170 is just an IP address for the internet I used while accessing Wikipedia with school campus Wi-Fi. Other people have edited under this IP. Sausage Link of High Rule (talk) 21:03, 1 September 2022 (UTC)

A bit confused about Basal Eurasians

If Mesolithic European hunter-gatherers split off from Basal Eurasians before they split off from East Eurasians, wouldn't that make West Eurasian more of a geographic thing (very distinct lineages in an area mixed to form one population) than a distinct genetic lineage since some populations dubbed West Eurasian (i.e. Natufians, Neolithic Iranians) have heavy amounts of Basal Eurasian ancestry? Wouldn't Mesolithic European hunter-gatherers have had to split from Basal Eurasians after they split off from East Eurasians for West-Eurasian to be a lineage basal to East Eurasians? (Unless, of course, West-Eurasian doesn't include Basal Eurasians) Or are these populations dubbed West Eurasian in spite of the Basal Eurasian ancestry, instead acknowledging the non-Basal Eurasian ancestry? Honestly I am rather confused about this. Sausage Link of High Rule (talk) 05:29, 17 September 2022‎ (UTC)

Hey, Sausage Link of High Rule, a good question. If I may add my commentary here, it is more accurate to say that "West-Eurasians" formed by varying degrees of admixture between "Basal-Eurasians" (true "West-Eurasians") and a lineage (simply "Eurasian"?) which split slightly later from "eastern non-Africans/East-Eurasians". Before that merging, there were no West-Eurasians in any modern day sense. But do not forget the split times! After the OOA, so called Basal-Eurasians stayed in the Middle East, while the remainder humans migrated towards Iran. There, shortly after the Basal-Eurasians diverged, they again split (a population ancestral to Mesolithic Europeans). Distinctive East-Eurasians only evolved in South Asia after both groups already diverged from them. You can compare that with this diverging pattern proposal:[1]. If we go by geography, Basal-Eurasians are the "true West-Eurasians", while modern West-Eurasians are characterized by this "basal western ancestry" and a kind of "neo-West-Eurasian ancestry", which diverged from the yet largely undifferentiated human core population, somewhere on the Iranian plateau, before the formation of proper East-Eurasians. Another (warning original research!) proposal I heard of suggests that Basal-Eurasians = Real West-Eurasians, while modern West-Eurasians recived varying degrees of (deep) East-Eurasian like admixture (different amounts than basal vs neo). Similarly explaining the shift of Europeans towards eastern populations, compared to Middle Easterners, which have more hypothetical Basal ancestry. Its quite complex, but actually no one can say for sure. Hopefully more papers will be published. I know one which may interest you: [2]. It simply seems that basal eurasians (middle easterners) simply split before paleolithic europeans split from East-Eurasians (varying time dephts...), but modern West-Eurasians (Middle Easterners and Europeans) formed from these two early split populations.

Deep population structure of western Eurasians

"Our study comprises the largest genomic dataset on European hunter-gatherers to date, including 113 imputed hunter-gatherer genomes of which 79 were sequenced in this study. Among them, we report a 0.83X genome of an Upper Palaeolithic (UP) skeleton from Kotias Klde Cave in Georgia, Caucasus (NEO283), directly dated to 26,052 - 25,323 cal BP (95%). In the PCA of all non-African individuals, it occupies a position distinct from other previously sequenced UP individuals, shifted towards west Eurasians along PC1 (Supplementary Note 3d). Using admixture graph modelling, we find that this Caucasus UP lineage derives from a mixture of predominantly West Eurasian UP hunter-gatherer ancestry (76%) with ~24% contribution from a “basal Eurasian” ghost population, first observed in West Asian Neolithic individuals29 (Extended Data Fig. 5A). Models attempting to reconstruct major post-LGM clusters such as European hunter-gatherers and Anatolian farmers without contributions from this Caucasus UP lineage provided poor admixture graph fits or were rejected in qpAdm analyses (Extended Data Fig. 5B,C). These results thus suggest a central role of the descendants related to this Caucasus UP lineage in the formation of later West Eurasian populations, consistent with recent genetic data from the nearby Dzudzuana Cave, also in Georgia30."

Its still a preprint, but may be usefull once it is published...Bharat99x2 (talk) 10:05, 17 September 2022 (UTC)

Thank you for this insight! I'm still a little confused though. Does this mean WHG and ANE aren't "true West Eurasian", and are rather more of "neo-West Eurasian" or para-East Eurasian population compared to Basal Eurasians? Sausage Link of High Rule (talk) 04:48, 18 September 2022 (UTC)

It seems to me that the term West-Eurasian, in common use, more so refers to the group that split from East-Eurasians later on, or on the modern populations of Western Eurasia, while Basal Eurasian is kind of its own thing, a hypothetical lineage is basal to both West and East Eurasians. Sausage Link of High Rule (talk) 22:31, 20 September 2022 (UTC)