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By constructing the first fine-scale map of the British Isles, Oxford University researchers have uncovered distinct geographical groupings of genetically similar individuals across the UK.
The study, published in the journal Nature, found that:
- There was no single 'Celtic' genetic group. In fact the Celtic parts of the UK (Scotland, Northern Ireland, Wales and Cornwall) are among the most different from each other genetically. For example, the Cornish are much more similar genetically to other English groups than they are to the Welsh or the Scots.
- There are separate genetic groups in Cornwall in Devon, with a division almost exactly along the modern county boundary.
- The majority of eastern, central and southern England is made up of a single, relatively homogeneous, genetic group with a significant DNA contribution from Anglo-Saxon migrations (10-40% of total ancestry). This settles a historical controversy in showing that the Anglo-Saxons intermarried with, rather than replaced, the existing populations.
- The population in Orkney emerged as the most genetically distinct, with 25% of DNA coming from Norwegian ancestors. This shows clearly that the Norse Viking invasion (9th century) did not simply replace the indigenous Orkney population.
- The Welsh appear more similar to the earliest settlers of Britain after the last ice age than do other people in the UK.
- There is no obvious genetic signature of the Danish Vikings, who controlled large parts of England ('The Danelaw') from the 9th century.
- There is genetic evidence of the effect of the Landsker line – the boundary between English-speaking people in south-west Pembrokeshire (sometimes known as 'Little England beyond Wales') and the Welsh speakers in the rest of Wales, which persisted for almost a millennium.
- The analyses suggest there was a substantial migration across the channel after the original post-ice-age settlers, but before Roman times. DNA from these migrants spread across England, Scotland, and Northern Ireland, but had little impact in Wales.
- Many of the genetic clusters show similar locations to the tribal groupings and kingdoms around end of the 6th century, after the settlement of the Anglo-Saxons, suggesting these tribes and kingdoms may have maintained a regional identity for many centuries.