A large-scale genomic study of Mesolithic populations in the Dnieper-Don region has revealed the earliest known genetic adaptation to tick-borne encephalitis. Published in Cell Genomics, the research analyzed 9,000-year-old skeletal remains and identified a localized expansion of the OAS1 gene cluster. This genetic signature, which provides enhanced antiviral resistance, was crucial for hunter-gatherers transitioning into the dense, forested river valleys of Eastern Europe following the retreat of the ice sheets.
The study marks a significant advance in paleo-pathogen research, demonstrating how ancient human genomes can be used to track the history of zoonotic diseases. The researchers found that this resistance marker was maintained as these foragers eventually integrated with early Neolithic farmers, suggesting that disease pressure was a major driver of post-glacial population structure. These findings highlight the role of ecological 'hotspots' in shaping the genetic immune profile of modern European and Western Asian populations.