A genetic study of 132 people buried in a large megalithic tomb near Paris has uncovered evidence of a dramatic population collapse and replacement during the Stone Age — solving a mystery that has puzzled archaeologists for decades.
Published in Nature Ecology & Evolution, the study shows that the burial site near Bury, about 50 kilometers north of Paris, was used during two distinct periods divided by a major population decline around 3000 BC. The people buried before and after the collapse were not genetically related.
"We see a clear genetic break between the two periods," said Frederik Valeur Seersholm, assistant professor at the University of Copenhagen and lead author. "The earlier group resembles Stone Age farming populations from northern France and Germany, while the later group shows strong genetic links to southern France and the Iberian Peninsula."
A Crisis of Disease and Environmental Stress
The researchers used advanced DNA techniques to examine all genetic material preserved in the bones. They found traces of several pathogens, including Yersinia pestis (the bacterium that causes plague) and Borrelia recurrentis (which causes louse-borne relapsing fever).
However, the team says plague alone doesn't explain what happened. "The evidence does not support it as the sole cause of the population collapse," said Martin Sikora, senior author. "The decline was likely driven by a combination of disease, environmental stress, and other disruptive events."
The skeletal remains point to an unusually severe crisis: archaeologists found exceptionally high mortality during the earlier burial period, especially among children and young people — a classic demographic signature of catastrophe.
A Social Revolution
The genetic evidence also reveals that the population replacement was accompanied by profound social changes. During the earlier period, the tomb contained multiple generations of the same extended families — close-knit communities burying relatives together over time. In the later period, burials became highly selective, dominated by a single male lineage — indicating a completely different social structure.
Why the Megaliths Stopped
The finding may finally explain why the construction of megalithic tombs and other massive stone monuments — such as those at Carnac in France — came to an end across Europe during roughly the same period.
"We now see that the end of these monumental constructions coincides with the disappearance of the population that built them," Seersholm said.
The study adds to growing evidence that the Neolithic population decline affected large parts of northern and western Europe, extending well beyond Scandinavia and northern Germany — and rewrites the story of who built Europe's most ancient monuments.
