Here is a very interesting blog posting by Dick Eastman. It is about an article published in Harvard Magazine.
Dick Eastman's blog says:
"Harvard Magazine has an interesting story concerning history and, for many of us, our distant ancestors. The article is subtitled, "The written record of history meets genomics, evolution, demography, and molecular archaeology.'
Historians know that something dramatic happened in England just as the Roman empire was collapsing. When the Anglo-Saxons ﬁrst arrived in the fourth century A.D.--whether as immigrants or invaders is debated--they encountered an existing Romano-Celtic population estimated at between 2 million and 3.7 million people. Latin and Celtic were the dominant languages.
The ensuing cultural transformation was so complete, says Goelet professor of medieval history Michael McCormick, that 400 years later, English civilization considered itself completely Anglo-Saxon, and spoke only Anglo-Saxon. This extraordinary change has had ramiﬁcations down to the present, and is why so many people speak English rather than Latin or Celtic today. But how English culture was completely remade, the historical record does not say.
Then, in 2002, scientists found a genetic signature in the DNA of living British men that hinted at an untold story of Anglo-Saxon conquest.
My thanks to Richard P Draves for telling me about this article."
The full article is available by clicking on this link: Who Killed the Men of England? | Harvard Magazine July-August 2009