Why the Megalithic Building Boom in Europe

4,500 years ago a megalithic building boom mushroomed in Europe with great stone monuments popping up around the Baltic Sea.

In a new study published in the Proceedings of the National Academy of Sciences, an international research team, led from Uppsala University, discovered kin relationships among Stone Age individuals buried in megalithic tombs on Ireland and in Sweden. The kin relations can be traced for more than ten generations and suggests that megaliths were graves for kindred groups in Stone Age northwestern Europe.

Agriculture spread with migrants from the Fertile Crescent into Europe around 9,000 BCE, reaching northwestern Europe by 4,000 BCE. Starting around 4,500 BCE, a new phenomenon of constructing megalithic monuments, particularly for funerary practices, emerged along the Atlantic façade. These constructions have been enigmatic to the scientific community, and the origin and social structure of the groups that erected them has remained largely unknown. The international team sequenced and analysed the genomes from the human remains of 24 individuals from five megalithic burial sites, encompassing the widespread tradition of megalithic construction in northern and western Europe.

The Ansarve site on the island of Gotland in the Baltic Sea is embedded in an area with mostly hunter-gathers at the time.

Credit: Magdalena Fraser

The team collected human remains of 24 individuals from megaliths on Ireland, in Scotland and the Baltic island of Gotland, Sweden. The remains were radiocarbon-dated to between 3,800 and 2,600 BCE. DNA was extracted from bones and teeth for genome sequencing. The team compared the genomic data to the genetic variation of Stone Age groups and individuals from other parts of Europe. The individuals in the megaliths were closely related to Neolithic farmers in northern and western Europe, and also to some groups in Iberia, but less related to farmer groups in central Europe.

The team found an overrepresentation of males compared to females in the megalith tombs on the British Isles.

“We found paternal continuity through time, including the same Y-chromosome haplotypes reoccurring over and over again,” says archaeogeneticist Helena Malmström of Uppsala University and co-first author. “However, female kindred members were not excluded from the megalith burials as three of the six kinship relationships in these megaliths involved females.”

The team found an overrepresentation of males compared to females in the megalith tombs on the British Isles.

Credit:  Göran Burenhult

A likely parent-offspring relation was discovered for individuals in the Listhogil Tomb at the Carrowmore site and Tomb 1 at Primrose Grange, about 2 km distance away from each other.