Gurun, K. | bioRxiv Science

bioRxiv2022

A genomic snapshot of demographic and cultural dynamism in Upper Mesopotamia during the Neolithic Transition

Upper Mesopotamia played a key role in the Neolithic Transition in Southwest Asia through marked innovations in symbolism, technology, and foodways. We present thirteen ancient genomes (c.8500-7500 calBCE) from Pre-Pottery Neolithic Cayonu in the Tigris basin together with bioarchaeological and material culture data. Our findings reveal that Cayonu was a genetically diverse population, carrying a mixed ancestry from western and eastern Fertile Crescent, and that the community received immigrants. Our results further suggest that the community was organised along biological family lines. We document bodily interventions such as head-shaping and cauterization among the individuals examined, reflecting Cayonus cultural ingenuity. Finally, we identify Upper Mesopotamia as the likely source of eastern gene flow into Neolithic Anatolia, in line with material culture evidence. We hypothesise that Upper Mesopotamias cultural dynamism during the Neolithic Transition was the product not only of its fertile lands but also of its interregional demographic connections.

genetics↗

bioRxiv2020

Human inbreeding has decreased in time through the Holocene

The history of human inbreeding is controversial. The development of sedentary agricultural societies may have had opposite influences on inbreeding levels. On the one hand, agriculture and food surplus may have diminished inbreeding by increasing population sizes and lowering endogamy, i.e. inbreeding due to population isolation. On the other hand, increased sedentism, as well as the advent of private property may have promoted inbreeding through the emergence of consanguineous marriage customs or via ethnic and caste endogamy. The net impact is unknown, and to date, no systematic study on the temporal frequency of inbreeding in human societies has been conducted. Here we present a new approach for reliable estimation of runs of homozygosity (ROH) in genomes with [≥]3x mean coverage across >1 million SNPs, and apply this to 440 ancient Eurasian genomes from the last 15,000 years. We show that the frequency of inbreeding, as measured by ROH, has decreased over time. The strongest effect is associated with the Neolithic transition, but the trend has since continued, indicating a population size effect on inbreeding prevalence. We further show that most inbreeding in our historical sample can be attributed to endogamy, although singular cases of high consanguinity can also be found in the archaeogenomic record. HighlightsA study of 440 ancient genomes shows inbreeding decreased over time. The decrease appears linked with population size increase due to farming. Extreme consanguineous matings did occur among farmers, but rarely.

genomics↗