LONDON, ENGLAND, March 6, 2007: (HPI note: Genetic research is revising more than the history of ancient India.) 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.
Dr. Oppenheimer’s population history of the British Isles relies not only on genetic data but also on the dating of language changes by methods developed by geneticists. These are not generally accepted by historical linguists, who long ago developed but largely rejected a dating method known as glottochronology. Geneticists have recently plunged into the field, arguing that linguists have been too pessimistic and that advanced statistical methods developed for dating genes can also be applied to languages. Dr. Oppenheimer has relied on work by Peter Forster, a geneticist at Anglia Ruskin University, to argue that Celtic is a much more ancient language than supposed, and that Celtic speakers could have brought knowledge of agriculture to Ireland, where it first appeared. He also adopts Dr. Forster’s argument, based on a statistical analysis of vocabulary, that English is an ancient, fourth branch of the Germanic language tree, and was spoken in England before the Roman invasion. Historians have usually assumed that Celtic was spoken throughout Britain when the Romans arrived. But Dr. Oppenheimer argues that the absence of Celtic place names in England — words for places are particularly durable — makes this unlikely.
If the people of the British Isles hold most of their genetic heritage in common, with their differences consisting only of a regional flavoring of Celtic in the west and of northern European in the east, might that perception draw them together? Geneticists see little prospect that their findings will reduce cultural and political differences. The Celtic cultural myth “is very entrenched and has a lot to do with the Scottish, Welsh and Irish identity; their main identifying feature is that they are not English,” said Dr. Sykes, an Englishman who has traced his Y chromosome and surname to an ancestor who lived in the village of Flockton in Yorkshire in 1286. Dr. Oppenheimer said genes “have no bearing on cultural history.” There is no significant genetic difference between the people of Northern Ireland, yet they have been fighting with each other for 400 years, he said.
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.