The last hunter-gatherers of Western Europe lived on the Atlantic coast during the Mesolithic. Some of the most emblematic sites of this era are Champigny or Hoedic and Téviec, located in the south of Brittany (France).
They are open-air sites that are best known for their rich and exceptionally well-preserved burial sites. Dozens of people were buried in the common graves of these places, especially the tomb of two young women who died violently and who were buried under a roof of antlers with their bodies decorated with jewelry made of shells.
All these skeletons have now allowed us to discover more details about the social customs of the Stone Age, including the strategy that hunter-gatherers followed to avoid incest in communities where blood relations and kinship were not so important.
Researchers at Uppsala University have carried out a new genetic study of the remains of 10 individuals and discovered that several different families lived together. “This was probably a deliberate system to avoid inbreeding,” they say in an article published in the journal Proceedings of the National Academy of Science (PNAS).
The analysis of Finnish specialists has made it possible to obtain biomolecular data from human skeletons dating back approximately 6,700 years, a time in which the last hunter-gatherers of Western Europe coincided in time with the arrival of farmers who were taking control of the continent.
“This offers a new picture of the last nomadic populations of the Stone Age. Our research provides a unique opportunity to analyze these groups and their social dynamics,” says Professor Mattias Jakobsson, who led the study.
About 7,500 years ago, the last hunter-gatherer populations of Western Europe encountered Neolithic farmers and were gradually replaced and assimilated. The coexistence of these groups has raised many questions about the extent to which they interacted with each other.
Previous analyzes based on isotopic data have suggested that late nomadic communities deliberately assimilated women from the new agricultural society of the Neolithic. But Uppsala experts disagree with this hypothesis and claim that hunter-gatherers mixed with other hunter-gatherer tribes, but not with farmers.
“Our genomic analyzes show that, although these groups consisted of few individuals, they were generally not closely related. Furthermore, there were no signs of inbreeding. However, we know that there were different social units – with different eating habits – and a group pattern emerged that was probably part of a strategy to avoid incest,” says researcher Luciana G. Simões.
The well-known Téviec and Hoedic sites, excavated between 1928 and 1934, contain numerous tombs in which several people were buried together. This is unusual in Mesolithic cemeteries and so it was previously assumed that being buried in the same tomb meant that individuals were biologically related.
“Our results show that in many cases – even in the case of women and children in the same grave – the individuals were not genetically connected. This suggests that there were strong social ties that had nothing to do with biological kinship and that these relationships remained important even after death,” says Dr. Amélie Vialet, from the National Museum of Natural History.
These latter collectors “were part of a network of people who maintained exogamous practices (they looked for spouses from other tribes or people from other localities or communities). Partner exchange networks also seem to be exclusive to the feeding group,” the study authors point out.
“The low intragroup biological relationship prevented consanguineous mating, despite the small population size of the Late Mesolithic hunting groups,” they add. Exchange with neighboring tribes, furthermore, was limited to other hunter-gatherers, excluding Neolithic farmers.
