New research published in natural ecology and evolution They examined the bodies of 132 people buried in large megalithic tombs near Berry, about 50 kilometers north of Paris. The site was used during two different periods, during which a significant population decline occurred around 3,000 BC.
Genetic analysis shows that the people buried before and after this decline are unrelated, suggesting large-scale population turnover.
“There is a clear genetic disconnect between these two periods,” said Frederik Valeur-Sielsholm, assistant professor at the Grove Institute at the University of Copenhagen and one of the study’s lead authors.
“Earlier groups resemble the Stone Age farming peoples of northern France and Germany, while later groups show strong genetic links to southern France and the Iberian Peninsula.”
These results indicate a rapid decline in the local population followed by the arrival of new groups migrating from the south.
Evidence of disease and high mortality rate
To better understand the causes of this decline, researchers used DNA technology that captures all the genetic material stored in bones. This approach has revealed traces of ancient pathogens, including Yersinia pestis. plague bacterium Microorganisms that cause louse-borne relapsing fever, Borrelia recurrentis.
“While we can confirm that plague existed, the evidence does not support that plague was the sole cause of the population collapse,” said Martin Sikora, associate professor at the University of Copenhagen and lead author of the study. “This decline may have been caused by a combination of disease, environmental stress, and other destructive events.”
Examination of human remains also revealed an unusually high mortality rate, especially among children and young people, during the early stages of burial.
“Demographics are a strong indicator of crisis,” said Laure Salanova, head of research at France’s National Center for Scientific Research (CNRS).
Changes in social structure after the collapse
Genetic discoveries also highlight significant variation in how these communities are organized.
Early indications were that the people buried in the tombs were often members of the same extended family, suggesting a close-knit group spanning multiple generations. In contrast, later burials were more selective and centered primarily around a single male lineage.
“This shows that changes in population were accompanied by changes in the structure of society,” Schiersholm said.
Part of Europe’s overall decline
The study adds to the evidence that the so-called Neolithic decline affected large parts of northern and western Europe, beyond Scandinavia and northern Germany.
It may also help explain why construction of megalithic tombs and other large stone monuments ceased throughout Europe during this period.
“We now understand that the demise of these monumental structures coincides with the disappearance of the populations that built them,” Schiersholm said.
