A genetic study of 132 people buried in a large megalithic tomb near Bary, about 50 kilometers north of Paris, has revealed evidence of dramatic population collapse and replacement during the Stone Age. Conclusion, published in Nature Ecology and Evolutionshow that the burial site was used during two distinct periods, divided by a major population decline around 3000 BC.
DNA analysis revealed that the people buried before and after the collapse were not closely related to each other, suggesting that the original population largely disappeared and was replaced by new people.
“We see a clear genetic difference between the two periods,” said Fredrik Veleur Syrsholm, an assistant professor at the Globe Institute at the University of Copenhagen and one of the study’s lead authors.
“The former group resembles the Stone Age farming populations of northern France and Germany, while the latter group shows stronger genetic links with southern France and the Iberian Peninsula.”
The results show that the local population declined dramatically before new groups migrated north and settled in the area.
Symptoms of ancient disease and crisis
To investigate what might be causing the decline, the researchers used a DNA technique that examines all the genetic material preserved in the ancient bones. This allowed them to identify markers of many pathogens, including yersinia pestisthe bacteria responsible for plague, and Borrelia recurrentisWhich causes relapsing fever caused by lice.
Although plague was present, researchers say it doesn’t fully explain what happened.
“We can confirm that plague was present, but the evidence does not support it as the sole cause of population decline,” said Martin Sikora, an associate professor at the University of Copenhagen and senior author of the study. “This decline was likely driven by a combination of disease, environmental stress, and other disruptive events.”
The skeletal remains also point to unusually severe distress. Archaeologists found exceptionally high mortality rates during the first burial period, especially among children and youth.
“Demographic patterns are a strong indicator of the crisis,” said Laure Salanova, research director at France’s National Center for Scientific Research (CNRS).
DNA reveals changes in Stone Age society
Genetic evidence also shows that population replacement was accompanied by significant social changes.
During earlier periods, graves contained multiple generations of the same extended families, suggesting close-knit communities that buried relatives together over time. In later periods, burials became much more selective and dominated by a single male lineage, indicating a different social organization.
“This indicates that along with population changes came changes in the structure of society,” Syrsholm said.
A Clue to the End of Europe’s Megalith Builders
The findings add to growing evidence that Neolithic population declines affected large parts of northern and western Europe, extending beyond Scandinavia and northern Germany.
The study may also help explain why construction of megalithic tombs and other giant stone monuments stopped throughout Europe during roughly the same period.
“We now see that the end of these monumental constructions coincides with the disappearance of the populations that built them,” Syrsholm said.