Artist's impression of an Upper Paleothic burial from Sunghir, Russia, issued by Cambridge University, credit Libor Balak, Anthropark

A paleolithic burial site in Russia has provided evidence that prehistoric humans formed complex mating networks to avoid inbreeding.

A new study examined genetic information from the remains of modern humans who lived during the early part of the Upper Palaeolithic, a period when modern humans from Africa first colonized western Eurasia, eventually displacing the Neanderthals who lived there before.

The humans buried at the site in Sunghir, Russia were no more closely related than first cousins. The findings suggest that they deliberately sought partners beyond their immediate family, and that they were probably connected to a wider network of groups from within which mates were chosen.

The work was carried out a research team led by the University of Cambridge (U.K.) and the University of Copenhagen, Denmark, and including SMU archaeologist David J. Meltzer, whose expertise includes the First People in the Americas. Their findings are reported in “Ancient genomes show social and reproductive behavior of early Upper Paleolithic foragers,” published in the Oct. 5, 2017 issue of Science.

The researchers’ work demonstrate that by at least 34,000 years ago, human hunter-gatherer groups had developed sophisticated social and mating networks that minimized inbreeding. The authors also hint that the early development of more complex mating systems may at least partly explain why modern humans proved successful while other, rival species, such as Neanderthals, did not. More ancient genomic information from both early humans and Neanderthals is needed to test this idea.

The human fossils buried at Sunghir are a unique source of information about early modern human societies of western Eurasia. Sunghir preserves two contemporaneous burials – that of an adult man, and that of two children buried together and which includes the symbolically modified remains of another adult.

To the researchers’ surprise, however, these individuals were not closely related in genetic terms; at the very most, they were second cousins. This is true even for the two children who were buried head-to-head in the same grave.

“What this means is that people in the Upper Palaeolithic, who were living in tiny groups, understood the importance of avoiding inbreeding,” said Eske Willerslev, a professor at St. John’s College and the University of Copenhagen, who was senior author on the study. “The data that we have suggest that it was being purposely avoided. This means that they must have developed a system for this purpose. If the small hunter and gathering bands were mixing at random, we would see much greater evidence of inbreeding than we have here.”

— University of Cambridge, SMU

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