STOCKHOLM, Sweden, April 2 (UPI) -- Stone Age hunter-gatherers who lived along the southern coast of Scandinavia 4,000 years ago were unable to digest milk, researchers said.
The findings support a widely held theory that modern Scandinavians descended from people who arrived in the area after the Stone Age population.
Unlike modern Scandinavians, the DNA of the hunter-gathers shows they were lactose intolerant, said researchers at Stockholm University and Uppsala University.
The ability to digest milk is closely associated with the transition from hunter-gatherer populations to agricultural societies, said researcher Anders Gotherstrom.
Gotherstrom is the coordinator of a European Union-funded project focusing on the significance of milk in European prehistory.
"The findings are indicative of what we call 'gene flow,' in other words, migration to the region at some later time of some new group of people, with whom we are genetically similar," Gotherstrom said.