Steppe Maykop: a buffer zone?

Unfortunately, the ancient data from the Wang et al. preprint still haven't been released online. As I've already pointed out many times, the manuscript conclusion looks horribly contrived (for instance, see here), but the data are awesome, and most of the preprint is quite solid.

One thing that I'd really like to do is to compare in detail each of the ancient populations from the preprint to groups of present-day and ancient speakers of Indo-European and Caucasian languages. What's the bet that, by and large, Eneolithic steppe will show strong links to Indo-Europeans, while Eneolithic Caucasus and Maykop to Caucasians?

But pending the release of the data, all I can do is look at what the authors have done with it.

Intriguingly, their analyses suggest that the Eneolithic steppe genotype may have vanished from the steppes abutting the Caucasus by at least 3500 BC. It seems to have been replaced there by a more heterogeneous gene pool, with both more easterly and southerly genetic affinities, associated with the Steppe Maykop archeological culture.

So who were the Steppe Maykop people and why did they show up, rather suddenly, in the North Caucasus steppes to seemingly clear out the Eneolithic steppe population from the region? I have a theory about that.

Both archeological and ancient DNA data show that the North Caucasus was being colonized by groups from Transcaucasia during the Eneolithic. But apparently this wasn't an entirely smooth and safe process, because these southern settlers were forced to build elaborate fortifications to keep the natives at bay. Indeed, at the site of Meshoko, in the Northwest Caucasus, there is evidence of such a fort being overrun and its community replaced, probably by a nearby indigenous group (see here).

On the other hand, during the Bronze Age Maykop period, the relations between the settlers from the south and the steppe peoples were apparently much more peaceful. So much so, in fact, that Maykop settlements weren't fortified. However, this was also the period when the North Caucasus steppes were home to the Steppe Maykop people.

So here's my theory: either by chance or design, Steppe Maykop territory was a buffer zone between Maykop and the potentially aggressive natives of the steppes to the north. I'm not necessarily suggesting that the Steppe Maykop people were foreign mercenaries hired by Maykop chiefs, but, in any case, they may have benefited economically in a variety of ways by keeping Maykop settlements safe.

Around 3000 BC, both Maykop and Steppe Maykop disappeared. The latter was replaced by the Yamnaya culture. I don't know much about this process. It may have been mostly driven by environmental impacts from climate change. But the fact that the Steppe Maykop population didn't contribute much, if any, ancestry to the Yamnaya people in the region suggests to me that it was a hostile takeover by Yamnaya.

Interestingly, the spread of Yamnaya into the North Caucasus steppes saw the return of the Eneolithic steppe genotype to the region, albeit in a modified form, with admixture from Middle Neolithic European farmers (see here).

See also...

Yamnaya: home-grown

A potentially violent end to the Kura-Araxes Culture (Alizadeh et al. 2018)

Y-haplogroup P1 in Pleistocene Siberia (Sikora et al. 2018 preprint)

Over at bioRxiv at this LINK. Below is the abstract, emphasis is mine. Two of the (unrelated) males from Yana RHS belong to Y-haplogroup P1 and mitochondrial haplogroup U2. Note that P1 is ancestral to Y-haplogroups Q and R.

Far northeastern Siberia has been occupied by humans for more than 40 thousand years. Yet, owing to a scarcity of early archaeological sites and human remains, its population history and relationship to ancient and modern populations across Eurasia and the Americas are poorly understood. Here, we report 34 ancient genome sequences, including two from fragmented milk teeth found at the ~31.6 thousand-year-old (kya) Yana RHS site, the earliest and northernmost Pleistocene human remains found. These genomes reveal complex patterns of past population admixture and replacement events throughout northeastern Siberia, with evidence for at least three large-scale human migrations into the region. The first inhabitants, a previously unknown population of "Ancient North Siberians" (ANS), represented by Yana RHS, diverged ~38 kya from Western Eurasians, soon after the latter split from East Asians. Between 20 and 11 kya, the ANS population was largely replaced by peoples with ancestry from East Asia, giving rise to ancestral Native Americans and "Ancient Paleosiberians" (AP), represented by a 9.8 kya skeleton from Kolyma River. AP are closely related to the Siberian ancestors of Native Americans, and ancestral to contemporary communities such as Koryaks and Itelmen. Paleoclimatic modelling shows evidence for a refuge during the last glacial maximum (LGM) in southeastern Beringia, suggesting Beringia as a possible location for the admixture forming both ancestral Native Americans and AP. Between 11 and 4 kya, AP were in turn largely replaced by another group of peoples with ancestry from East Asia, the "Neosiberians" from which many contemporary Siberians derive. We detect additional gene flow events in both directions across the Bering Strait during this time, influencing the genetic composition of Inuit, as well as Na Dene-speaking Northern Native Americans, whose Siberian-related ancestry components is closely related to AP. Our analyses reveal that the population history of northeastern Siberia was highly dynamic, starting in the Late Pleistocene and continuing well into the Late Holocene. The pattern observed in northeastern Siberia, with earlier, once widespread populations being replaced by distinct peoples, seems to have taken place across northern Eurasia, as far west as Scandinavia.

Sikora et al., The population history of northeastern Siberia since the Pleistocene, bioRxiv, posted October 22, 2018, doi: https://doi.org/10.1101/448829

See also...

Ust'-Ishim belongs to K-M526

Greeks in a Longobard cemetery

I designed a new Principal Component Analysis (PCA) to help me test the fine scale genetic affinities of post-Bronze Age ancient samples from Southern Europe and surrounds. Below is a version of this PCA with a selection of the most Southern European-related ancients from this year's Amorim et al. and Veeramah et al. papers (for background reading, see the posts and comments here and here). The relevant datasheet is available here.

A number of people in the comments at this blog and elsewhere were especially curious about the potential genetic origins of the three most Near Eastern-shifted individuals from the Amorim et al. dataset: CL25, CL30 and CL38. Judging from my new PCA, it seems likely to me that this trio came to North Italy from the pre-Slavic invasions Aegean region. In other words, I'd say they're probably Roman era Greeks or their descendants, who, unlike most present-day Greeks, don't harbor any Slavic ancestry. That's because they cluster very strongly with present-day Greeks from Crete, and also more or less sit on a cline running from present-day mainland Greeks to Cypriots.

See also...

Mediterranean PCA update

Celtic vs Germanic Europe