The archaeological site of Ajvide in Sweden, dating back approximately 5,500 years, is renowned for its particularly well-preserved graves. At that time, while agriculture was becoming widespread in Europe, communities in the north maintained a lifestyle based on seal hunting and fishing.
Thanks to scientists from Uppsala University, the DNA of ten individuals from four collective graves has been analyzed. Their work, published in Proc Biol Sci, shows that people buried together were often distant relatives, such as cousins or uncles.
Ancient graves at Ajvide in Sweden provide new clues about social life in the Stone Age. DNA analysis indicates that hunter-gatherers took extended family relationships into account during burials. Here, a girl and a young woman were third-degree relatives.
Credit: Johan Norderäng
This is a surprise for the researchers. To illustrate this point, one burial contained a young woman accompanied by two children who were not hers, but probably her nephews or nieces. Another grave also held two children, a boy and a girl, identified as cousins by genetic analysis.
These burial configurations demonstrate that knowledge of family lineage extended beyond the immediate nuclear family. Thus, second- or third-degree relationships held an important place in the rites, a sign of social recognition of extended bonds.
To establish these kinships, the researchers compared the proportion of shared DNA. First-degree relatives, such as parents and children, share approximately 50% of their DNA, while cousins share about 12.5%.
This discovery thus provides a new angle on the social organization of hunter-gatherers. It indicates that communities placed importance on extended kinship networks, which could solidify group cohesion and chances of survival.
Going forward, this pilot project plans to examine more than 70 additional individuals from Ajvide. The objective is to refine the understanding of the life stories and burial traditions of these ancient populations.