The early farming way of life of the Neolithic period originated more than 10,000 years ago in the Middle East, from where it spread across Europe and significantly shaped human history. With the production and storage of food, structures based on territorial claims and possessions gradually emerged and contributed to the development of social hierarchies. After the first settlement phase, complex social structures quickly established themselves, which were also reflected in the burial customs.
For example, the Paris Basin in modern-day France is known for monumental stone buildings that were considered burial grounds for the social elite. In this context, the burial ground of Gurgy “Les Noisat” is also of particular interest, one of the largest Neolithic necropolises without stone structures, and the question arose as to who was buried there.
With the help of new methods for obtaining and analyzing ancient DNA and sampling almost all of the 128 burials at the site, a research team from the PACEA laboratory in Bordeaux, France, and the Max Planck Institute for Evolutionary Anthropology in Leipzig has now been able to reconstruct two unexpectedly large family trees , which provide direct insights into the living environment of this prehistoric community.
Genealogical trees of impressive size
In their study, the researchers present the genome-wide data of 94 individuals from Gurgy, which they evaluated in connection with strontium isotope data and the extended archaeological and anthropological context such as age at death, biological sex and location in the burial ground. The larger of the two pedigrees includes 64 individuals over seven generations, the smaller twelve individuals over five generations.
“From the start of the excavation, we found evidence that the burial site was very deliberately used. There are hardly any overlapping burials, which means that the necropolis was managed by close relatives who must have known very well who was buried where,” says archaeologist and anthropologist Stéphane Rottier of the University of Bordeaux, who excavated the site between 2004 and 2007 and has documented. And indeed, the evaluating team was able to demonstrate a statistically significant correlation between physical distance and the degree of biological relatedness of the individuals.
Insights into the social structure of the Gurgy community
The pedigrees show clear indications of patrilinearity, since the generations are linked almost exclusively via the biological fathers and only two Y-chromosomal lines, which are inherited purely from the father, are proven. At the same time, however, there is a high diversity of mitochondrial DNA, which is inherited from the mother’s side and was refreshed in each new generation in Gurgy.
Together with the results of the strontium isotope analyses, which show that these mothers carry more non-local signatures, this points to practices of virilocality and female exogamy (“outside marriage”). The sons stayed in the community and had partners from outside. In fact, the adult daughters are missing from the family trees, which means that they had, as it were, left the community to form new bonds elsewhere, most likely in mutual exchange. Interestingly, some of the women who married in were distantly related, suggesting that Gurgy was in such exchange alliances with a few neighboring communities.
Maïté Rivollat, first author of the study, is impressed by the pedigrees: »We see a large number of full siblings, all of whom had reached the age of reproduction. If we then add a hypothetical number of individuals for an even sex ratio and some infant mortality, we get fairly large families and a high reproductive or fertility rate. This indicates an overall very good nutritional and health condition for the group, which is remarkable for prehistoric times.”
Another phenomenon is the absence of half-siblings, which is a direct indication of monogamous relationships. On the one hand, this can mean that a partner died less frequently, or that illegitimate offspring were not buried in this cemetery due to social sanctions.
The ancestral line
With regard to the primarily virilocal system, one man stands out who has been identified as the ‘founding father’ of the great family tree. His burial is also exceptional, as his bones (actually just a bundle of the long bones) were placed as a secondary burial in the grave of a woman from whom, unfortunately, no genetic data could be obtained. The bones of the founding father were therefore brought from the original settlement or burial place of the group. “He must have been of great importance to the community as an ancestor to be reburied by his relatives in Gurgy,” explains Marie-France Deguilloux from the University of Bordeaux, co-lead author of the study.
Although the main pedigree spans as many as seven generations, the demographic profile suggests that the locality was multi-generational from its inception. The lack of child burials in the first generations and of adults in the last generations suggests that the group had buried children who died prematurely at a previous location and that the same principle was repeated when the last generation of parents had already moved on to the next location. This shows a significantly shorter occupancy of the cemetery, i.e. more three to four than seven generations, which in turn fits well with the estimated duration of dwellings at this time and the depletion of local resources such as soil or firewood.
In combination with contextual data from other disciplines, for example on mobility, nutrition and age at death, the sensationally large family trees offer enormous potential for interpretation and thus represent a giant step towards understanding the social structures of prehistoric societies. »The major methodological advances in recent years have made it possible made to conduct studies of this magnitude. This makes a long-cherished dream of every archaeologist and anthropologist come true and opens the door to further insights into human history,” summarizes Wolfgang Haak from the Max Planck Institute for Evolutionary Anthropology and main author of the study.