Monday, August 7, 2017

Ancient Mesopotamian mtDNA

Once again, ancient DNA evidence shows that the paternal Y-DNA makeup of a population is more prone to shifting than its maternal mtDNA population. It is particularly notable that there is not a strongly discernible shift towards Caucasian/Iranian mtDNA as this shift is visible in the Y-DNA and autosomal DNA of the region in the same time period, as shown by other recent ancient DNA work.

This suggests in this particular case that greater Syrian population genetic change in the Holocene has been driven by male dominated introgression among elites, rather than by gender balanced folk migration. This sample does not, however, include population genetic shifts attributable to the rise of the Islamic Empire or the Ottoman period, which did occur (giving rise to east Eurasian admixture in Turkey, for example) and may have been more gender balanced.
North Mesopotamia has witnessed dramatic political and social change since the Bronze Age, but the impact of these events on its demographic history is little understood. 
Here we study this question by analysing the recently excavated Late Iron Age settlement of Çemialo Sırtı in Batman, southeast Turkey. Archaeological and/or radiocarbon evidence indicate that the site was inhabited during two main periods: the first half of the 2nd millennium BCE and the first millennium BCE. Çemialo Sırtı reveals nomadic items of the Early Iron Age, as well as items associated with the Late Achaemenid and subsequent Hellenistic Periods. 
Mitochondrial DNA (mtDNA) haplotypes from 12 Çemialo Sırtı individuals reveal high genetic diversity in this population, conspicuously higher than early Holocene west Eurasian populations, which supports the notion of increasing population admixture in west Eurasia through the Holocene. Still, in its mtDNA composition, Çemialo Sırtı shows highest affinity to Neolithic north Syria and Neolithic Anatolia among ancient populations studied, and to modern-day southwest Asian populations. Population genetic simulations do not reject continuity between Neolithic and Iron Age, nor between Iron Age and present-day populations of the region. Despite the region's complex political history and indication for increased genetic diversity over time, we find no evidence for sharp shifts in north Mesopotamian maternal genetic composition within the last 10,000 years.

Note that the "Europe" tag is not because Turkey is in Europe, but because of its relevance to European genetics as a potential place of origin of European population genetics.

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