Study: Farmer and hunter groups 'kept their distance' from each other in Stone Age

"When farmers showed up from the Near East about 7,500 years ago, eager to grow their grains in the soil of Central Europe, they were met by indigenous hunters and gatherers. The locals, apparently, did not welcome them with open arms." New research suggests that "for some 2,000 years, these distinct groups refused to mesh and would rarely cross their cultural boundaries to find a mate." [The Washington Post]