"There was not a 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 and 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."
DNA study shows Celts are not a unique genetic group - BBC News
http://www.bbc.com/news/science-environment-31905764
DNA Deciphers Roots of Modern Europeans - The New York Times
http://www.nytimes.com/2015/06/16/science/dna-deciphers-roots-of-modern-europeans.html?
BRITAIN ANGLO-SAXON GENETIC
2015, Nature FULL:
http://www.nature.com/nature/journal/v519/n7543/full/nature14230.html
2015: http://www.heritagedaily.com/2015/03/first-fine-scale-genetic-map-british-isles/107039 2015: http://www.abc.net.au/science/articles/2015/03/18/4200057.htm
2015: http://www.abc.net.au/science/articles/2006/07/19/1690600.htm
2015: http://www.bbc.com/news/science-environment-31905764 2011: http://etheses.dur.ac.uk/727/
2002: http://mbe.oxfordjournals.org/content/19/7/1008.full
GENETICS ANGLO-SAXON BRITAIN
"The Anglo-Saxons, Germanic tribes who lived in present-day Germany, northern Holland and Denmark, invaded Britain in 450 AD after the fall of the Roman empire.
They conquered England but were unable to penetrate far into the Celtic fringes of what are now Wales and Scotland. They coincidentally prompted an exodus of Britons to what is now Brittany, France.
The population of England at that time was probably around two million while the number of Anglo-Saxons was minute: the lowest estimate puts the number of migrants at less than 10,000 some 200 years after the invasion, although others put it at more than 100,000."
http://www.abc.net.au/science/articles/2006/07/19/1690600.htm
2011: http://etheses.dur.ac.uk/727/
and 2006, http://etheses.dur.ac.uk/727/1/17_-_Whence_came_the_English.pdf?DDD5+
