Caucasus hunter-gatherer

Caucasus hunter-gatherer (CHG), also called Satsurblia cluster, is an anatomically modern human genetic lineage, first identified in a 2015 study, based on the population genetics of several modern Western Eurasian (European, Caucasian and Near Eastern) populations.
The CHG lineage is suggested to have diverged from the ancestor of Western Hunter-Gatherers (WHGs) probably during the Last Glacial Maximum (sometimes between 45,000 to 26,000 years ago). They further separated from the "Anatolian Hunter Gatherer" (AHG) lineage later, sometimes between 25-14,000 years ago during the late LGM period. The Caucasus hunter-gatherers managed to survive in isolation since the late LGM period as a distinct population, and display high genetic affinities to Mesolithic and Neolithic populations on the Iranian plateau, such as a Neolithic specimen found in Ganj Dareh. The CHG display higher genetic affinities to European and Anatolian groups than Iranian hunter-gatherers do, suggesting a possible cline and geneflow into Mesolithic and Neolithic Iranian groups and less into CHG.
At the beginning of the Neolithic, at c. 8000 BC, they were probably distributed across western Iran and the Caucasus, and people similar to northern Caucasus and Iranian plateau hunter-gatherers arrived before 6000 BC in Pakistan and north-west India. A roughly equal merger between the CHG and Eastern Hunter-Gatherers in the Pontic–Caspian steppe resulted in the formation of the Western Steppe Herders (WSHs). The WSHs formed the Yamnaya culture and subsequently expanded massively throughout Europe during the Late Neolithic and Early Bronze Age circa 3000-2000 BC.
Origins
Jones et al. (2015) analyzed genomes from males from western Georgia, in the Caucasus, from the Late Upper Palaeolithic (13,300 years old) and the Mesolithic (9,700 years old). These two males carried Y-DNA haplogroup: J* and J2a, later refined to J1-FT34521, and J2-Y12379*, and mitochondrial haplogroups of K3 and H13c, respectively. Their genomes showed that a continued mixture of the Caucasians with Middle Eastern populations took place up to 25,000 years ago, when the coldest period in the last Ice Age started.
CHG ancestry was also found in an Upper Palaeolithic specimen from Satsurblia cave (dated ca. 11000 BC), and in a Mesolithic one from Kotias Klde cave, in western Georgia (dated ca. 7700 BC). The Satsurblia individual is closest to modern populations from the South Caucasus.
Vallini et al. 2022 argues that the dispersal and split patterns of West Eurasian lineages was not earlier than c. 38,000 years ago, with older Upper-Paleolithic European specimens, such as Zlaty Kun and Bacho Kiro, being unrelated to Western Hunter-gatherers.
Margaryan et al. (2017) analysing South Caucasian ancient mitochondrial DNA found a rapid increase of the population at the end of the Last Glacial Maximum, about 18,000 years ago. The same study also found continuity in descent in the maternal line for 8,000 years.
According to Narasimhan et al. (2019) Iranian farmer related people arrived before 6000 BCE in Pakistan and north-west India, before the advent of farming in northern India. They suggest the possibility that this "Iranian farmer–related ancestry [...] was [also] characteristic of northern Caucasus and Iranian plateau hunter-gatherers."
Proto-Indo Europeans
The ancestry of the Yamnaya people can be mostly modelled as an admixture of Eastern Hunter-Gatherers (EHGs) and a Near Eastern component related to Caucasus hunter-gatherers, Iranian Chalcolithic people, or a genetically similar population. Each of those two populations contributed about half the Yamnaya DNA. According to co-author Andrea Manica of the University of Cambridge:
According to Jones et al. (2015), Caucasus hunter-gatherers (CHG) "genomes significantly contributed to the Yamnaya steppe herders who migrated into Europe ~3,000 BCE, supporting a formative Caucasus influence on this important Early Bronze Age culture. CHG left their imprint on modern populations from the Caucasus and also central and south Asia possibly marking the arrival of Indo-Aryan languages."
Lazaridis et al. (2016) proposes a different people, likely from Iran, as the source for the Middle Eastern ancestry of the Yamnaya people, finding that "a population related to the people of the Iran Chalcolithic contributed ~43% of the ancestry of early Bronze Age populations of the steppe". That study asserts that these Iranian Chalcolithic people were a mixture of "the Neolithic people of western Iran, the Levant, and Caucasus Hunter Gatherers".
Gallego-Llorente et al. (2016) conclude that Iranian populations are not a likelier source of the 'southern' component in the Yamnaya than Caucasus hunter-gatherers.
Wang et al. (2018) analysed genetic data of the North Caucasus of fossils dated between the 4th and 1st millennia BC and found correlation with modern groups of the South Caucasus, concluding that "unlike today – the Caucasus acted as a bridge rather than an insurmountable barrier to human movement".
CHG admixture was also found in South Asia, in a possible marker of the Indo-Aryan migration there.
Ancient Greece and Aegean
Beyond contributing to the population of mainland Europe through Bronze Age pastoralists of the Yamnaya, CHG also appears to have arrived on its own in the Aegean without Eastern European hunter–gatherer (EHG) ancestry and provided approximately 9–32% of ancestry to the Minoans. The origin of this CHG component might have been Central Anatolia.
See also
Prehistoric Caucasus
Notes
References
Sources
Further reading
External links
Caucasus Hunter-Gatherer ancestry and Indo-Hittite
Peopling of Europe
Last Glacial Maximum
Mesolithic Europe
Mesolithic Asia
Upper Paleolithic Europe
Upper Paleolithic Asia
Prehistoric Caucasus
CHG
Indo-European genetics
Hunter-gatherers of Asia
Hunter-gatherers of Europe