History of the United Kingdom revealed in its genes

Invading Romans, Anglo-Saxons and Normans may have shaped the history, culture and language of the British Isles, but they left surprisingly few genetic traces of themselves behind. DNA samples from more than 2,000 people from rural parts of the United Kingdom reveal 17 subtly distinct groups that reflect the history of the islands, researchers report March 18 in Nature.

Among the surprises: Celtic-speaking groups in Ireland, Scotland, Wales and Cornwall on the southwest tip of England are genetically distinct from each other. Researchers had previously assumed that Celts were a uniform group that spread throughout the islands.

Welsh people appear to be descendants of the first British settlers after the Ice Age, the analysis found. The Welsh remained genetically isolated from the rest of Britain, and researchers could find no trace of Anglo-Saxon heritage in their DNA.

The study also reveals that after Roman rule, invading Anglo-Saxons didn’t wipe out and replace the Britons. Instead, they mixed and intermarried with them. People in central and southeastern England carry between 10 and 40 percent Anglo-Saxon ancestry, the researchers estimate.

There’s an adage that history is written by the winners, says Peter Donnelly of the University of Oxford. Similarly, archaeology tells its stories based on burials of wealthy people. But “genetics tells us what happens to the bulk of the people, the masses,” he says.