English Irish Scots They re All One Genes Suggest New York Times Page 1 of 4 March 5 2007 English Irish Scots They re All One Genes Suggest By NICHOLAS WADE Britain and Ireland are so thoroughly divided in their histories that there is no single word to refer to the inhabitants of both islands Historians teach that they are mostly descended from different peoples the Irish from the Celts and the English from the Anglo Saxons who invaded from northern Europe and drove the Celts to the country s western and northern fringes But geneticists who have tested DNA throughout the British Isles are edging toward a different conclusion Many are struck by the overall genetic similarities leading some to claim that both Britain and Ireland have been inhabited for thousands of years by a single people that have remained in the majority with only minor additions from later invaders like Celts Romans Angles Saxons Vikings and Normans The implication that the Irish English Scottish and Welsh have a great deal in common with each other at least from the geneticist s point of view seems likely to please no one The genetic evidence is still under development however and because only very rough dates can be derived from it it is hard to weave evidence from DNA archaeology history and linguistics into a coherent picture of British and Irish origins That has not stopped the attempt Stephen Oppenheimer a medical geneticist at the University of Oxford says the historians account is wrong in almost every detail In Dr Oppenheimer s reconstruction of events the principal ancestors of today s British and Irish populations arrived from Spain about 16 000 years ago speaking a language related to Basque The British Isles were unpopulated then wiped clean of people by glaciers that had smothered northern Europe for about 4 000 years and forced the former inhabitants into southern refuges in Spain and Italy When the climate warmed and the glaciers retreated people moved back north The new arrivals in the British Isles would have found an empty territory which they could have reached just by walking along the Atlantic coastline since there were still land bridges then across what are now English Channel and the Irish Sea This new population who lived by hunting and gathering survived a sharp cold spell called the Younger Dryas that lasted from 12 300 to 11 000 years ago Much later some 6 000 years ago agriculture finally reached the British Isles from its birthplace in the Near East Agriculture may have been introduced by people speaking Celtic in Dr Oppenheimer s view Although the Celtic immigrants may have been few in number they spread their farming techniques and their language throughout Ireland and the western coast of Britain Later immigrants arrived from northern Europe had http www nytimes com 2007 03 05 science 05cnd brits html ei 5070 en f70778a7a495 3 8 2007 English Irish Scots They re All One Genes Suggest New York Times Page 2 of 4 more influence on the eastern and southern coasts They too spread their language a branch of German but these invaders numbers were also small compared with the local population In all about three quarters of the ancestors of today s British and Irish populations arrived between 15 000 and 7 500 years ago when rising sea levels finally divided Britain and Ireland from the Continent and from one another Dr Oppenheimer calculates in a new book The Origins of the British A Genetic Detective Story Carroll Graf 2006 As for subsequent invaders Ireland received the fewest the invaders DNA makes up about 12 percent of the Irish gene pool Dr Oppenheimer estimates but it accounts for 20 percent of the gene pool in Wales 30 percent in Scotland and about one third in eastern and southern England Still no single group of invaders is responsible for more than 5 percent of the current gene pool Dr Oppenheimer says on the basis of genetic data He cites figures from the archaeologist Heinrich Haerke that the Anglo Saxon invasions that began in the fourth century A D added about 250 000 people to a British population of one to two million an estimate Dr Oppenheimer notes is larger than his but considerably less than the substantial replacement of the English population assumed by others The Norman invasion of 1066 A D brought not many more than 10 000 people according to Dr Haerke Other geneticists say Dr Oppenheimer s reconstruction is plausible though some disagree with details Several said that genetic methods did not give precise enough dates to be confident of certain aspects like when the first settlers arrived Once you have an established population it is quite difficult to change it very radically said Daniel G Bradley a geneticist at Trinity College Dublin But he said he was quite agnostic as to whether the original population became established in Britain and Ireland immediately after the glaciers retreated 16 000 years ago as Dr Oppenheimer argues or more recently in the Neolithic Age which began 10 000 years ago Bryan Sykes another Oxford geneticist said he agreed with Dr Oppenheimer that the ancestors of by far the majority of people were present in the British Isles before the Roman conquest of A D 43 The Saxons Vikings and Normans had a minor effect and much less than some of the medieval historical texts would indicate he said His conclusions based on his own genetic survey and information in his genealogical testing service Oxford Ancestors are reported in his new book Saxons Vikings and Celts The Genetic Roots of Britain and Ireland A different view of the Anglo Saxon invasions has been developed by Mark Thomas of University College London Dr Thomas and colleagues say the invaders wiped out substantial numbers of the indigenous population replacing 50 percent to 100 percent of those in central England Their argument is that the Y chromosomes of English men seem identical to those of people in Norway and the Friesland area of the Netherlands two regions from which the invaders may have originated http www nytimes com 2007 03 05 science 05cnd brits html ei 5070 en f70778a7a495 3 8 2007 English Irish Scots They re All One Genes Suggest New York Times Page 3 of 4 Dr Oppenheimer disputes this saying the similarity between the English and northern European Y chromosomes arises because both regions were repopulated by people from the Iberian refuges after the glaciers retreated Dr Sykes said he agreed with Dr Oppenheimer on this point but another geneticist Christopher