Ancient DNA reveals pervasive directional selection across West Eurasia - Nature

A genome-wide analysis of 15,836 ancient West Eurasian individuals finds hundreds of cases where allele frequencies changed steadily over time, demonstrating that directional selection was common across the region. The recent tooth analysis adds an independent line of physical evidence that interactions and interbreeding among ancient groups provided the demographic mixing that selection then acted upon. Together, the genetic, anatomical, and dental findings help connect long-term evolutionary change in populations with the social and biological interactions that generated variation.