Famine and disease may have driven ancient Europeans’ lactose tolerance

Ancient Europeans may have evolved an ability to digest milk thanks to periodic famines and disease outbreaks.

Europeans avidly tapped into milk drinking starting around 9,000 years ago, when dairying groups first reached the continent’s southeastern corner, researchers report July 27 in Nature. Yet it took several thousand years before large numbers of Europeans evolved a gene for digesting lactose, the sugar in milk, the investigators say.

These discoveries — based on animal fat residue samples from hundreds of archaeological sites and a trove of DNA data —…