Ars Technica reports on an interesting study of the “fine-scale genetic structure of the British population.” On their methods:
Obviously, people in the UK these days don’t always stick around where they were born, so people in a given region don’t necessarily share ancestry. But, if you can find people whose ancestry is closely tied to a particular region, it becomes possible to approximate what genomes would have been like a century ago, before people could move around so easily.
A paper published in Nature this week analyzed the genomes of 2039 people whose grandparents were all born within 80 kilometers (50 miles) of one another. This effectively meant that the researchers were sampling the genomes of the grandparents, whose average birth year was 1885 and who obviously had strong ties to a region. This allowed the researchers to investigate the genetic structure of the UK population before the mass movements of last century.
The researchers (mostly British and Australian) identified 17 “distinct clusters.” Also, “there was no identifiable, general ‘Celtic’ group. Samples from Orkney, Wales, Cornwall, and Devon were distinct from the rest of England and Scotland, but didn’t cluster together in any way. The Welsh populations show a stronger link than other groups to the first settlers of Britain after the last Ice Age.” And: “What was unexpected was the lack of clear evidence of Danish Viking occupation, which suggested that the Vikings didn’t mix much with the local population. While Orkney (part of Norway until 1472) showed a clear Norse genetic stamp, this didn’t show up much in the rest of the UK population.”
Cool map at the link.