Thirty thousand years ago, Europe was a land of open steppes with herds of grazing mammoth and other megafauna—and a strikingly uniform human culture. Its inhabitants, whom archaeologists call the Gravettians, dwelled in caves or in shelters built of mammoth bones. They carved palm-size sculptures from mammoth tusk, depicting mammoths, cave lions, and stylized female figurines with elaborate headdresses and exaggerated breasts and buttocks, and left their distinctive art and artifacts from Spain to western Russia. “You can make a case for saying the Gravettian is the first pan-European culture,” says University of Tübingen archaeologist Nicholas Conard.

But despite appearances, the Gravettians were not a single people. New DNA evidence, published today in Nature, shows Gravettians in France and Spain were genetically distinct from groups living in what is now the Czech Republic and Italy. “What we thought was one homogenous thing in Europe 30,000 years ago is actually two distinct groups,” says Mateja Hajdinjak, a molecular biologist at the Max Planck Institute for Evolutionary Anthropology who was not part of the new study.

The Gravettian data are part of a larger trove of ancient European DNA that reveals striking genetic diversity within apparently unified prehistoric cultures. The sweeping study analyzed 116 newly sequenced genomes and hundreds of previously published ones, ranging from about 45,000 years ago, when the first modern humans reached the continent, to about 6000 B.C.E., and from the Iberian Peninsula to the western steppes of modern-day Russia. It “fill[s] gaps in space and time,” says the study’s lead author, Cosimo Posth, a geneticist at Tübingen.

In period after period, the genetic evidence suggests conclusions drawn from archaeological evidence such a