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| Study Reveals Genetic Path of Modern Britons | Study Reveals Genetic Path of Modern Britons |
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| In A.D. 410, Roman authority in Britain collapsed and Romano-British society disappeared from history under the invading tides of Angles and Saxons from northern Europe. Historians have been debating ever since whether the Romano-British were wiped out or survived by adopting their conquerors’ language and culture. | In A.D. 410, Roman authority in Britain collapsed and Romano-British society disappeared from history under the invading tides of Angles and Saxons from northern Europe. Historians have been debating ever since whether the Romano-British were wiped out or survived by adopting their conquerors’ language and culture. |
| A fine-scale genetic analysis of the British population has now provided the answer. The invaders and the existing population lived side by side and eventually intermarried extensively. The people of south and central England are now genetically well mixed, with Saxon genes accounting for only about 20 percent of the mix, says a genetics team led by Stephen Leslie of the Murdoch Childrens Research Institute in Victoria, Australia, and by Peter Donnelly and Walter Bodmer of Oxford University. | A fine-scale genetic analysis of the British population has now provided the answer. The invaders and the existing population lived side by side and eventually intermarried extensively. The people of south and central England are now genetically well mixed, with Saxon genes accounting for only about 20 percent of the mix, says a genetics team led by Stephen Leslie of the Murdoch Childrens Research Institute in Victoria, Australia, and by Peter Donnelly and Walter Bodmer of Oxford University. |
| The British Isles were wiped clean of people by the glaciers that descended toward the end of the last ice age, and were repopulated some 10,000 years ago by people who trekked over the broad land bridge that then joined eastern England to Europe north of the Rhine. The researchers say they can identify the genetic signature of this early migration, which survives most strongly in people from the western extremity of Wales. | The British Isles were wiped clean of people by the glaciers that descended toward the end of the last ice age, and were repopulated some 10,000 years ago by people who trekked over the broad land bridge that then joined eastern England to Europe north of the Rhine. The researchers say they can identify the genetic signature of this early migration, which survives most strongly in people from the western extremity of Wales. |
| Another strong genetic signal comes from the Orkney Islands north of Scotland. Some 25 percent of the DNA of Orcadians is of Norwegian origin, which is consistent with Norway’s long ownership of the islands. | Another strong genetic signal comes from the Orkney Islands north of Scotland. Some 25 percent of the DNA of Orcadians is of Norwegian origin, which is consistent with Norway’s long ownership of the islands. |
| But the geneticists see no trace of the Danelaw, the Danish rule over northern England from the ninth to the 11th century, nor of the Norman conquest of England in 1066. The numbers of invaders may have been too small to leave a demographic imprint, and in the case of the Normans, who had previously emigrated from southern Denmark to Normandy, it is hard to distinguish their genes from those of the earlier Danish invaders. | But the geneticists see no trace of the Danelaw, the Danish rule over northern England from the ninth to the 11th century, nor of the Norman conquest of England in 1066. The numbers of invaders may have been too small to leave a demographic imprint, and in the case of the Normans, who had previously emigrated from southern Denmark to Normandy, it is hard to distinguish their genes from those of the earlier Danish invaders. |
| The people of the southern and central parts of England form a homogeneous population, but all around the Celtic periphery, in Cornwall, Wales and Scotland, lie small clusters of genetically different populations that have maintained their identity over the generations. This is a surprise, given that the Celtic peoples who ruled most of England until Caesar’s invasion in B.C. 55 were assumed to be fairly homogeneous. | The people of the southern and central parts of England form a homogeneous population, but all around the Celtic periphery, in Cornwall, Wales and Scotland, lie small clusters of genetically different populations that have maintained their identity over the generations. This is a surprise, given that the Celtic peoples who ruled most of England until Caesar’s invasion in B.C. 55 were assumed to be fairly homogeneous. |
| The explanation may have to do with the reach of Roman rule. In southern and central England, “the Romans controlled that area of Britain and introduced farming systems and roads and broke down many political barriers to movement,” said Mark Robinson, an archaeologist at Oxford and a co-author of the study, published in the journal Nature. The population under Roman rule thus became homogenized, whereas those beyond it would have remained politically fragmented, making travel and intermarriage difficult, Dr. Robinson said. | The explanation may have to do with the reach of Roman rule. In southern and central England, “the Romans controlled that area of Britain and introduced farming systems and roads and broke down many political barriers to movement,” said Mark Robinson, an archaeologist at Oxford and a co-author of the study, published in the journal Nature. The population under Roman rule thus became homogenized, whereas those beyond it would have remained politically fragmented, making travel and intermarriage difficult, Dr. Robinson said. |
| The researchers found that the modern British population falls into 17 clusters altogether, based on genetic relatedness. Though very similar, the groups are genetically distinguishable, and even the main population cluster, that of southern and central England, is distinguishable from the populations of France, Germany and other European countries. | The researchers found that the modern British population falls into 17 clusters altogether, based on genetic relatedness. Though very similar, the groups are genetically distinguishable, and even the main population cluster, that of southern and central England, is distinguishable from the populations of France, Germany and other European countries. |
| Dr. Donnelly, a population geneticist and co-author of the report, said the study was groundbreaking “because it is really the first time that scientists have looked in great detail within a country at the pattern of genetic variation.” | Dr. Donnelly, a population geneticist and co-author of the report, said the study was groundbreaking “because it is really the first time that scientists have looked in great detail within a country at the pattern of genetic variation.” |
| There has been considerable migration into Britain over the last century from many countries of the former British Empire and from elsewhere in continental Europe. Dr. Donnelly and his colleagues managed to sidestep this recent churning of the population history by seeking out elderly people who lived in rural areas and whose grandparents had been born locally. Because individual genomes are composed of random samples of the four grandparents’ DNA, the researchers were in effect looking two generations into the past and testing the population of the late 19th century. | |
| They analyzed the DNA of their 2,000 subjects at 500,000 sites along the genome, and then organized them into the 17 genetic clusters. They also analyzed the genomes of 6,000 Europeans in the same way, and could thus identify the source populations in Europe from which each of the 17 British clusters was derived. The migrations revealed in that way match the known historical record but also point to events that have not been recorded, such as a massive migration from northern France that accounts for about one-third of the ancestry of the average person in Britain. | They analyzed the DNA of their 2,000 subjects at 500,000 sites along the genome, and then organized them into the 17 genetic clusters. They also analyzed the genomes of 6,000 Europeans in the same way, and could thus identify the source populations in Europe from which each of the 17 British clusters was derived. The migrations revealed in that way match the known historical record but also point to events that have not been recorded, such as a massive migration from northern France that accounts for about one-third of the ancestry of the average person in Britain. |
| “History is written by the winners, and archaeology studies the burials of wealthy people,” Dr. Donnelly said. “But genetic evidence is interesting because it complements that by showing what is happening to the masses rather than the elite.” | “History is written by the winners, and archaeology studies the burials of wealthy people,” Dr. Donnelly said. “But genetic evidence is interesting because it complements that by showing what is happening to the masses rather than the elite.” |