Characterizing the genetic history of admixture across inner Eurasia
The indigenous populations of inner Eurasia, a huge geographic region covering the central Eurasian steppe and the northern Eurasian taiga and tundra, harbor tremendous diversity in their genes, cultures and languages. In this study, we report novel genome-wide data for 763 individuals from Armenia, Georgia, Kazakhstan, Moldova, Mongolia, Russia, Tajikistan, Ukraine, and Uzbekistan. We furthermore report genome-wide data of two Eneolithic individuals (~5,400 years before present) associated with the Botai culture in northern Kazakhstan. We find that inner Eurasian populations are structured into three distinct admixture clines stretching between various western and eastern Eurasian ancestries. This genetic separation is well mirrored by geography. The ancient Botai genomes suggest yet another layer of admixture in inner Eurasia that involves Mesolithic hunter-gatherers in Europe, the Upper Paleolithic southern Siberians and East Asians. Admixture modeling of ancient and modern populations suggests an overwriting of this ancient structure in the Altai-Sayan region by migrations of western steppe herders, but partial retaining of this ancient North Eurasian-related cline further to the North. Finally, the genetic structure of Caucasus populations highlights a role of the Caucasus Mountains as a barrier to gene flow and suggests a post-Neolithic gene flow into North Caucasus populations from the steppe.
https://www.biorxiv.org/content/biorxiv/ear...327122.full.pdfFigure 6. The Greater Caucasus mountain ridge as a barrier to genetic exchange. Barriers (brown)
857 and conduits (green) of gene flow around the Caucasus region are estimated by the EEMS program. Red
858 diamonds show the location of vertices to which groups are assigned. A strong barrier to gene flow
859 overlaps with the Greater Caucasus mountain ridge reflecting the genetic differentiation between
860 populations of the north and south of the Caucasus. The barrier becomes considerably weaker in the
861 middle where present-day Ossetians live.
Рисунок 6. Горный хребет Большого Кавказа как барьер для генетического обмена. Барьеры (коричневые)
857 и проходы (зеленый) потока генов вокруг региона Кавказа оцениваются программой EEMS. красный
858 показывают расположение вершин, которым назначены группы. Сильный барьер для потока генов
859 перекрывается с горным хребтом Большого Кавказа, отражающим генетическую дифференциацию между
860 популяций севера и юга Кавказа. Барьер становится значительно слабее в
861, где живут нынешние осетины.