Archaeologists have long been fascinated by the megalithic burial grounds scattered across northern Europe, including those at the most famous site, Stonehenge. But although these stone monuments have yielded scores of ancient remains, they aren’t good at giving up another secret: how the people buried there were related. Now, a controversial study using new DNA sequencing technology has revealed that, in at least four sites in Ireland, Scotland, and Sweden, the interred men were closely related, suggesting to some a patrilineal society.
“It is without any doubt an interesting paper,” says Bettina Schulz Paulsson, a prehistoric archaeologist at the University of Gothenburg in Sweden who specializes in megalith origins. But, she adds, the numbers of sites and bodies “are far too little” to know the social structures of these early communities.
For decades, archaeologists have exhumed ancient remains at megalithic sites, from Carnac in the Brittany region of France to Sweden’s Ale’s Stones. In recent years, researchers have managed to coax mitochondrial DNA from some skeletons, revealing links down the female line that shed light—not on familial relations—but on early migration patterns. (Mitochondrial DNA is passed only from mothers to their children.) Recent improvements to DNA sequencing technology and statistical and collection methods have made it possible to sequence ancient nuclear DNA, which can also reveal relationships between male relations.
Paleogenomicist Federico Sánchez-Quinto from Uppsala University in Sweden used these techniques on dozens of remains from four megalithic tombs in Ireland, Scotland, and Sweden that were first uncovered years ago. He and his team sequenced the nuclear genomes of those remains—most of which have been dated to between 4500 B.C.E. and 3000 B.C.E.
The remains represented 18 men and six women. When the researchers looked for strings of genetic code that would indicate how closely the buried individuals were related, they found close kinships among men at the Scottish and Swedish sites. And at one of two Irish sites, Primrose Grange on the country’s northwestern coast, at least six of the nine men, who spanned up to 12 generations, shared a genetic variant, suggesting they descended from the same paternal line. One man is likely the father of a 5500-year-old body found at another megalithic site just 2 kilometers to the west.
Some anthropologists think burial in these monumental sites was likely a mark of high social status. The authors argue that, taken together, those results suggest European megalithic societies at the time were patrilineal, with social power invested in the male line across multiple generations, they report today in the Proceedings of the National Academy of Sciences.
The findings are intriguing, says Thomas Kador, an archaeologist at University College London. He notes that even though men were more commonly interred in these sites, the women there seem to have been given identical burials. That suggests to him that even if these societies were patrilineal, women still played significant roles. Kador’s team has also done a separate genome-wide analysis of ancient individuals at a different megalithic site in Ireland and found a notable lack of close kinship among the buried. It’s possible that different megalithic societies on the island had very different social structures and funerary practices, he says.
Indeed, Robert Hensey, an archaeologist at the National University of Ireland in Galway, warns against drawing such sweeping conclusions about the many and varied Neolithic societies of northern and western Europe from a handful of sites and a few dozen people. “It strains credulity.”
Megalith tombs were family graves in European Stone Age
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 in Ireland and Sweden. The kin relations can be traced for more than 10 generations and suggest 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 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 over-representation 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 genetic data show close kin relationships among the individuals buried within the megaliths. A likely parent-offspring relation was discovered for individuals in the Listhogil Tomb at the Carrowmore site and Tomb 1 at Primrose Grange, about two kilometers away from each other. "This came as a surprise. It appears as these Neolithic societies were tightly knit with very close kin relations across burial sites," says population-geneticist Federico Sanchez-Quinto of Uppsala University and co-first author.
The Ansarve site on the island of Gotland in the Baltic Sea is embedded in an area with mostly hunter-gathers at the time. "The people buried in the Ansarve tomb are remarkably different on a genetic level compared to the contemporaneous individuals excavated from hunter-gather-contexts, showing that the burial tradition in this megalithic tomb, which lasted for over 700 years, was performed by distinct groups with roots in the European Neolithic expansion," says archaeogeneticist Magdalena Fraser of Uppsala University and co-first author.
"That we find distinct paternal lineages among the people in the megaliths, an overrepresentation of males in some tombs, and the clear kindred relationships point to towards the individuals being part of a patrilineal segment of the society rather than representing a random sample from a larger Neolithic farmer community," says Mattias Jakobsson, population-geneticist at Uppsala University and senior author of the study.
"Our study demonstrates the potential in archaeogenetics to not only reveal large-scale migrations, but also inform about Stone Age societies and the role of particular phenomena in those times such as the megalith phenomena," says Federico Sanchez-Quinto.
"The patterns that we observe could be unique to the Primrose, Carrowmore, and Ansarve burials, and future studies of other megaliths are needed to tell whether this is a general pattern for megalith burials," says osteoarchaeologist Jan Storå of Stockholm University.