Archaeologists have drawn up what they believe is the world’s oldest family tree of an extended family found buried together more than 5,000 years ago.
An international team has worked on the analysis of ancient DNA from one of the best-preserved Neolithic tombs in Britain.
They found that most of the people buried there were from five continuous generations of a single extended family.
Buy they also believe that other individuals may be step-children, suggesting blended families may be far from a recent phenomenon.
The research, published in Nature on Wednesday, provides new insights into kinship and burial practices in Neolithic times, the authors said.
They said these developments have been made possible due to excellent DNA preservation in the group, who lived around 3700-3600 BC – about 100 years after farming had been introduced to Britain – before they were entombed in the Hazleton North long cairn, in the Cotswolds.
The DNA extracted from the bones and teeth of 35 individuals showed that 27 of them were close biological relatives.
The team – which included archaeologists from Newcastle University, and geneticists from the University of the Basque Country, University of Vienna and Harvard University – used this to map the relationships and produced what they say is the the first study to reveal in detail how prehistoric families were structured.
They found that most of those buried in the tomb were descended from four women who had all had children with the same man.
Men were generally buried with their father and brothers, suggesting that descent was patrilineal with later generations buried at the tomb connected to the first generation entirely through male relatives.
Although two of the daughters of the lineage who died in childhood were buried in the tomb, the absence of adult daughters suggests that their remains were placed either in the tombs of male partners, or elsewhere.
The discovery in the tomb of males whose mother was also in the structure but not their biological father indicates that stepsons were adopted into the lineage, the researchers said.
The team found no evidence that another eight individuals were biological relatives of those in the family tree, which might further suggest that biological relatedness was not the only criterion for inclusion.
Lead archaeologist of the study, Chris Fowler of Newcastle University, said that “just one extraordinary finding” is that two separated chambers in the tomb were used to place remains from one of two branches of the same family.
Dr Fowler said: “This study gives us an unprecedented insight into kinship in a Neolithic community.”
Inigo Olalde of the University of the Basque Country and Ikerbasque, the lead geneticist for the study, said: “The excellent DNA preservation at the tomb and the use of the latest technologies in ancient DNA recovery and analysis allowed us to uncover the oldest family tree ever reconstructed and analyse it to understand something profound about the social structure of these ancient groups.”
The project was an international collaboration between archaeologists from the Universities of Newcastle, York, Exeter and Central Lancashire, and geneticists at the University of Vienna, University of the Basque Country and Harvard University.