Neolithic family trees reveal social organization of prehistoric community

Around 12,000 years ago, the Neolithic lifestyle emerged in the Near East, shifting from hunting and gathering to farming. This transition led to the development of settled societies with new social customs based on wealth, resulting in the formation of social hierarchies. As farming spread to western Europe, societies became more complex, evident in their funerary practices.

One notable site is Gurgy “Les Noisats” in the Paris Basin region of northern modern-day France, a significant Neolithic funerary site without a monument. Researchers from the PACEA laboratory in Bordeaux, France, and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, used new DNA analysis methods to study the individuals buried there. Their findings revealed two extensive family trees, offering insights into the lives of the prehistoric community. The study has been published in the journal Nature.

Massive family trees

The study conducted by scientists involved analyzing various data sources from 94 individuals buried at Gurgy. They used genome-wide ancient DNA data, strontium isotope ratios, mitochondrial DNA (maternal lineages), Y-chromosome data (paternal lineages), age-at-death, and genetic sex. The analysis allowed them to reconstruct two family trees.

The first family tree linked 64 individuals across seven generations, making it the most extensive pedigree reconstructed from ancient DNA up to that point. The second family tree connected twelve individuals over five generations. These findings provide valuable insights into the ancestral relationships and social structures of the prehistoric community at Gurgy. The research sheds light on the lives of individuals buried there and enhances our understanding of ancient societies.

Reconstructed family tree of the largest genetically related group in Gurgy: The painted portraits are an artistic interpretation of the individuals based on physical traits estimated from DNA (where available). The dotted squares (genetically male) and circles (genetically female) represent individuals who were not found at the site or did not provide sufficient DNA for analysis. Credit: Drawing by Elena Plain; reproduced with the permission of the University of Bordeaux / PACEA

According to Stéphane Rottier, the archaeo-anthropologist who led the excavation between 2004 and 2007, the evidence found during the excavation pointed towards a strong control of the funerary space. Overlapping burials were rare, suggesting that the site was managed by a group of closely related individuals or at least by people who had knowledge of the burial locations. The study revealed a positive correlation between spatial and genetic distances, indicating that individuals were likely buried near their relatives. This finding provides significant insight into the social dynamics and familial connections within the prehistoric community at the Gurgy “Les Noisats” site.

Insights into the social structure of Gurgy

The exploration of pedigrees at Gurgy revealed a strong patrilineal pattern, with each generation predominantly connected through the biological father. This patrilineal linkage formed a continuous chain connecting the entire community at Gurgy through the paternal line.

In contrast, evidence from mitochondrial lineages and strontium isotope analysis pointed to a different practice for women. Most women appeared to have a non-local origin, indicating patrilocality, where sons stayed in their birth community and partnered with females from outside Gurgy. This settling with the male partner’s home community is known as virilocality.

Interestingly, the adult daughters in the lineage were mostly absent, suggesting female exogamy and a potential reciprocal exchange system. These “new incoming” females were not closely related to each other, indicating they likely came from a network of nearby communities, forming a wide and potentially fluid exchange network involving several groups.

The family trees revealed a large number of full siblings who reached reproductive age, along with equal numbers of males and females and a significant number of deceased infants. These findings suggest large family sizes, high fertility rates, and generally stable health and nutrition conditions, which is remarkable for such ancient times.

Another unique feature at Gurgy is the absence of half-siblings, indicating neither polygamous nor serial monogamous reproductive partnerships, or the exclusion of offspring from these unions from the main cemetery. This is distinct from other examples of union practices observed in Neolithic megaliths so far.

A founding ancestor

In the context of the patrilocal system, researchers identified a male individual as the “founding father” of the cemetery, from whom everyone in the largest family tree was descended. His burial was unique, as his skeletal remains were placed as a secondary deposit inside the grave pit of a woman, for whom unfortunately, no genomic data could be obtained. This suggests that his bones were brought from elsewhere to be reburied at the Gurgy site, indicating his great significance to the founders of the site.

The main pedigree spans seven generations, but the demographic profile indicates that a large family group, spanning several generations, arrived at the site. Initially, few subadults were buried at the site, followed by no adult burials in the last generations, suggesting a short use of the site. The group likely left a previous site, leaving behind deceased children, but they brought the lineage father with them.

A similar pattern emerged later when the adults of the last generations left Gurgy for another place, leaving their own children behind. As a result, Gurgy was likely used for only three to four generations, roughly about a century.

The largest pedigrees reconstructed from ancient human DNA data, along with multiple lines of evidence, mark a significant advancement in our understanding of past societies’ social organization. The integration of context data and recent advances in the field allowed for this extraordinary study, fulfilling the dreams of anthropologists and archaeologists and opening new avenues for studying the ancient human past.

Source: Max Planck Society

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