Stone Age Burial Site Reveals Deep Family Trees and Complex Social Structures

Sweden - Ekhbary News Agency

Stone Age Burial Site Reveals Deep Family Trees and Complex Social Structures

A remarkable discovery at the Ajvide archaeological complex on the Swedish island of Gotland is challenging long-held assumptions about family structures in Stone Age societies. Researchers investigating genetic relationships among individuals buried at the site, which dates back approximately 5,500 years, have found that burial companions were not always close relatives. Instead, many individuals shared genetic links indicating they were second or third-degree relatives, such as cousins or aunts/uncles and nieces/nephews, rather than just parents, children, or siblings.

This finding, published in the journal *Proceedings of the Royal Society B Biological Sciences*, suggests a more intricate social organization among these hunter-gatherer communities than previously understood. "Surprisingly enough, the analysis showed that many of those who were buried together were second- or third-degree relatives, rather than first-degree relatives—in other words, parent and child or siblings—as is often assumed," stated Helena Malmström, an archaeogeneticist at Uppsala University and lead author of the study. "This suggests that these people had a good knowledge of their family lineages and that relationships beyond the immediate family played an important role."

The study focused on four graves within the Ajvide site, a location known for its well-preserved evidence of a hunter-gatherer culture that thrived as agriculture was becoming widespread across much of Europe. The team extracted DNA from the bones and teeth of the deceased to determine their sex and familial connections. The degree of shared DNA allowed them to reconstruct kinship relationships: first-degree relatives share approximately 50% of their DNA, second-degree relatives (like half-siblings or grandparents and grandchildren) share about 25%, and third-degree relatives (such as cousins or great-aunts/uncles) share around 12.5%.

The genetic analysis yielded intriguing details about the relationships within these ancient graves. In one instance, a 20-year-old woman was found buried alongside two young children. The DNA confirmed the children were full siblings, and the woman was likely their aunt or half-sister, highlighting a multi-generational family unit or extended kinship network within the burial context.

Another grave contained the remains of a young girl next to her adult father. While the original placement of the father's remains might have been altered, the genetic link is clear. A third grave revealed two children related at the third degree, likely cousins, and a fourth grave contained a young woman and a girl, also third-degree relatives, possibly a cousin or great-aunt pairing.

These four graves are part of a larger funerary site at Ajvide, which includes 85 known burials, with eight identified as shared graves. "The analyses provide insight into social organisation in the Stone Age," commented Paul Wallin, an expert on the Ajvide burial ground. The ability to determine sex from DNA (based on X and Y chromosomes) and then map familial links provided a detailed picture of social connections.

The preservation of these hunter-gatherer graves is exceptionally rare, making such kinship studies invaluable. "As it is unusual for these kinds of hunter-gatherer graves to be preserved, studies of kinship in archaeological hunter-gatherer cultures are scarce and typically limited in scale," noted Tiina Mattila, a population geneticist at Uppsala University and co-author of the study. This research significantly expands the scope and depth of our understanding.

Looking ahead, the research team plans to conduct interdisciplinary studies on over 70 individuals from the same site. They anticipate further insights into the life histories, burial customs, and complex social organization of these ancient peoples. This ongoing work promises to paint an even richer picture of Stone Age life, emphasizing the enduring significance of family and kinship ties across millennia.

Ekhbary News Agency