The social organization of a Neolithic community is revealed through extensive genealogy
A genealogy of a prehistoric family tree revealed by ancient DNA from relocated remains: Implications for union networks and social activity in an early farming community
The male descendant of dozens of the other people buried nearby was identified by Ancient DNA from the relocated remains. This insight comes from a study that used ancient genomics to build the largest-ever genealogy of a prehistoric family, providing a snapshot of life in an early farming community. The study was published in the journal Nature.
This contrasts with a United Kingdom Neolithic burial where a man and four women were found. Chris Fowler, an archeologist who was part of the study, said that researchers need to build family trees from other ancient burials to figure out what is typical.
Further insights into the group’s social organization can be obtained from the fact that there are no half-siblings in the entire sample. This means that polygamous reproductive unions were uncommon or socially proscribed, or that the burial of offspring from such unions was carried out elsewhere. Likewise, it also suggests that serial monogamy, including levirate and sororate unions in which a woman repartners with her deceased husband’s brother or a man repartners with his wife’s sister, was rare. We find this observation surprising given potential imbalances in the female/male sex-ratio, for example, an elevated risk of death from complications during childbirth (for female individual), potential conflicts or diseases in prehistoric societies. The pedigrees show no evidence in support of these assumptions. If reproductive unions were contracted with a lot of groups for purposes of alliance or trade, then between-group networks of cooperation, instead of conflict, are implied.
In the mid-2000s, archaeologists excavating a burial site in France uncovered a 6,500-year-old mystery. Among the remains of more than 120 individuals, one grave stood out. It contained a nearly complete female skeleton alongside a few assorted bones that looked like they had been dug up and moved from another grave.
But they were astounded to discover that around two-thirds belonged to a single family tree that spanned seven generations. The people were buried very close to each other.
His team used the data they gathered from the 94 individuals that were analysed to find out who they were related to. The researchers expected some individuals to be related, based on the composition of other Neolithic sites.
The spatial organization of the graves was investigated and we saw that every father and son pair were close to each other. There are patterns of spatial organization beyond the specific father–son connections, which follow clusters of genetically closely related individuals. There were siblings buried near each other after the initial burials in the eastern part of the funerary area. For example, the four siblings of individual GLN317 were buried west of him, whereas the mother of his sons was buried east of him, and GLN223 and his son’s daughter was buried on top of him. The other son of GLN 304, GLN 202, died after being buried in another part of the necropolis along with other family members, and was possibly the last one of this family line. Using a Geographic Information System we were able to analyze the distribution of grave goods and adornments attributed to the dead. However, perhaps due to the general paucity of grave goods at the site (Supplementary Table 21), no association was detected. There was no correlation between the different body positions and grave and genetic families. The pattern of expansion suggests that people knew where their loved one was buried, and the layout indicates that graves were visible or marked on the surface. We observed a trend of males and females being related through the male line, potentially indicative of local understandings of genealogy or descent.
The Gurgy group’s presumed patrilocal residential pattern helps explain the diversity of the mitochondrial haplogroups despite a deficit in female adults (50 different haplogroups are carried by 99 individuals). The female descendant of the main line of mtDNA was the only one who transmitted her own line further than one daughter or son generation. We found that all of the female adults were not related apart from two pairs of relatives. Moreover, this female diversity within the Gurgy group might also explain the overall phenotypic variation observed at the site (Supplementary Note 9 and Supplementary Tables 15 and 16). Taken together, these results suggest that the majority of female exogamy in the Gurgy community is probably due to group features, for example the population size, resource access, and network position. The lack of long runs of Homozygosity (ROH) in close kin consanguinity shows the avoidance of reproduction between closely related individuals except for a single individual. I share information which reveals that groups of individuals are in the same genealogy. A are connected to each other more than expected. If additional relatives were present through maternal lines, this can be explained. Some mothers were probably from the same group, only several generations apart, which would link the different branches of the family tree. For example, siblings GLN243A and GLN268B share the same mitochondrial haplotype H1 as GLN315 (Supplementary Table 5) and IBD-sharing typical of third-degree relationships, whereas GLN315 is an exogenous female individual. The relationship between GLN315 and the missing mother is believed to be second degree. These additional connections through the female lines indicate a network of relationships with other groups, including occasional unions with (distantly) related women from the same source group. This pattern suggests preferential links or dependencies between some groups, albeit within a network of groups sufficiently large or diverse to sustain diversity of background relatedness and to avoid close-kin consanguinity.
