In parts of Bronze Age Greece, marrying a first cousin wasn't just tolerated, it was almost the normal thing to do. This surprising conclusion was reached by experts from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany along with an international team of partners.
In a peer-reviewed study published in the scientific journal Nature Ecology & Evolution, the scientists analyzed genome data from 102 ancient individuals from Crete, the Aegean Islands and the Greek mainland, spanning from the Neolithic to the Iron Age.
Frequent first-cousin marriages
The data revealed a rate of close-family intermarriage unprecedented in the global ancient DNA record. One particularly interesting set of genomes comes from a tomb buried under the courtyard of a house in a Mycenaean village on the Greek mainland, showing evidence of the frequent unions of first cousins.
“We managed to construct the first family pedigree for the Mediterranean. We can see who lived together in this house from looking at who was buried outside in the courtyard," Archaeologist Prof. Philipp Stockhammer, one of the lead authors, told CNN.
“We could see, for example, that the three sons lived as adults in this house. One of the marriage partners brought her sister and a child. It’s a very complex group of people living together.”
“People have studied thousands of ancestral genomes and there’s hardly any evidence for societies in the past of cousin-cousin marriage. From a historical perspective this really is outstanding,” he added.
A complete surprise
At this point, the team of researchers can only speculate about the reasons for the prevalence of this peculiar practice. "Maybe this was a way to prevent the inherited farmland from being divided up more and more? In any case, it guaranteed a certain continuity of the family in one place, which is an important prerequisite for the cultivation of olives and grapes, for example," Stockhammer suspects.
"More than a thousand ancient genomes from different regions of the world have now been published, but it seems that such a strict system of kin marriage did not exist anywhere else in the ancient world," says Dr. Eirini Skourtanioti, who conducted the analyses. "This came as a complete surprise to all of us and raises many questions."
"What is certain is that the analysis of ancient genomes will continue to provide us with fantastic, new insights into ancient family structures in the future," adds Skourtanioti.