Below is an interesting article from the Telegraph on the findings.
By Harriet Cooke2:12PM BST 17 Jun 2012
Scientists drew up a map of the British Isles revealing the genetic ancestry of people from different rural areas across the UK.
After extensive DNA surveying, they found that Welsh and Cornish people were among the most genetically distinct groups in the country.
One theory for the difference in their DNA is that they are a "relic" population, tracing their ancestry back to the tribes that colonised Britain after the last Ice Age 10,000 years ago.
Welsh genes proved to be similar to those of the French and Irish, suggesting they were connected to the pre-Roman population.
The Cornish were also shown to have a distinctive DNA make-up, different to those from the neighbouring county Devon.
Peter Donnelly, professor of statistical science at Oxford University and director of the Wellcome Trust centre for human genetics, confirmed the distinctiveness of people from the two regions.
He said: "The people of Wales and Cornwall are different from the rest of southern and central England."
But the most genetically distinctive of all British people were those of the Orkneys, who were shown to have Scandinavian ancestry, dating back to when their islands were controlled by Vikings from AD875 to 1472.
It may come as a surprise to the people of Norfolk that their DNA was little different to those in the rest of the south.
Tradition has it that residents from the area are descended from the ancient Iceni tribe.
Some 2,000 rural dwellers were analysed in the survey, and all had to have four grandparents born in the same area.
Those in south east and central England were described by Donnelly as "a real genetic cocktail", with parts of their DNA matching the pre-Roman population, Anglo-Saxon and the Danish Viking settlers.
Donelly and his team will be presenting their work at the Royal Society's summer science exhibition, to be held in London on July 3 - 8.http://www.telegraph.co.uk/science/science-news/9336923/Welsh-and-Cornish-are-the-purest-Britons-scientists-claim.html