The invisible genetic barrier that divided western Eurasia in prehistory

A new international study, involving Sapienza University of Rome, demonstrated the existence of two groups of culturally but also genetically different populations in the area from the Black Sea to the Baltic Sea region during the Mesolithic and Neolithic periods. The results, obtained through the analysis of more than 1,600 ancient human genomes, have been published in the journal Nature

An international researcher team, including Dušan Borić from the Department of Environmental Biology of Sapienza University of Rome, analysed a large dataset of ancient DNA, demonstrating the existence of genetic, as well as cultural, differences between the ancient western populations of Eurasia.

For some time now, archaeologists have been pointing to the existence of an alleged cultural barrier during the Mesolithic and Neolithic periods, stretching from the Black Sea to the Baltic. Within this geographical area, culturally distinct groups adopted different ways of life, including food supply. By aligning archaeological knowledge with comprehensive analysis of ancient DNA, researchers have now identified the existence of an invisible genetic barrier across Europe in this “Great Divide” phenomenon. The results of the study have been published in the journal Nature

In particular, analyses of ancient bones and teeth from specimens dating back more than 11,000 years confirmed a genetic difference between the populations east of the Great Divide who maintained complex societies of hunters, fishermen and gatherers, and the inhabitants to the west who gradually became farmers until the transition to the Bronze Age, around 4,000 years ago, when the Great Divide began to decline.

Although the ancient DNA in many samples was extremely degraded, the application of the latest technological breakthroughs in the field of DNA extraction and sequencing to a major earlier Bronze Age study made it possible to go even further back in time and analyse more than 300 genomes dating back to the Mesolithic and Neolithic periods. These data could then be combined with those already published to create a considerable dataset of over 1,600 ancient human genomes.

In order to map entire genomes from highly fragmented ancient DNA, the researchers used a method called imputation, an advanced mathematical model that allows them to fill gaps in irregular ancient genomes. The model's predictions are based on the analysis of a large number of complete genomes of current individuals.Thanks to this method, it is possible to reconstruct missing sequences with such precision that ancient human genomes can be used for large-scale genomic analyses of populations.

"Sapienza's contribution to this study," says Dušan Borić, "is linked to evidence from the site of Lepenski Vir, the region of the Danube gorges between present-day Serbia and Romania, which represents the key site for understanding the dynamics of interaction between the local populations of hunter-gatherers and the groups of farmers who settled during the transition to agriculture”.



Population genomics of post-glacial western Eurasia - Allentoft, M.E., Sikora, M., Refoyo-Martínez, A. et al. - Nature (2024).


Further Information

Dušan Borić
Department of Environmental Biology 

Monday, 12 February 2024

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