The idea of significant Ancient North Eurasian (ANE) admixture in Caucasus Hunter-Gatherers (CHG) was rejected in the paper that introduced us to the CHG metapopulation (see page 3 here). But to me it seems like an obvious conclusion when looking at the positions of the CHG genomes on a typical West Eurasian Principal Component Analysis (PCA) plot. For instance, see here. Note their massive eastern shift relative to all of the other present-day and ancient Near Eastern samples, in particular the Anatolian Neolithic farmers from Mathieson et al. 2015. We'll probably find out what's causing this shift in the next major paper on Eurasian paleogenomics. But I'd say that the analyses below, based on D-stats and f3-stats, comparing CHG genome Kotias to the Anatolian farmers, provide persuasive evidence that CHG is indeed admixed with ANE or something very closely related. Perhaps surprisingly, the Itelmen people of eastern Siberia produce the most significant Z-score in D-stats of the form D(Chimp,X)(Anatolia_Neolithic,Kotias), where X is every population from North and East Eurasia and the Americas in my dataset likely to harbor ANE. Mal'ta boy or MA1, the main ANE proxy, is way down the list with a non-significant (<3) result. However, I'm pretty sure that a higher coverage sequence with over 500K SNPs would come through with the goods.
CHG admixture in early western Anatolian farmers