Friday, June 27, 2014
Geneticists have uncovered a legacy of "prehistoric genocide" in the west of Scotland, with almost a third of the region's men descended from a band of early farmers whose skills in metalwork and porridge-making helped wipe out rivals
Researchers working on the Scotland's DNA project have identified the area around Glasgow as a hotspot for a key genetic marker which can be traced back to early settlers known as the Beaker People after the pottery they created. The marker, known to scientists as R1b-S145, has been detected at rates of 31% in the area compared to 20% to 22% in the east. It is carried on the Y chromosome and passed down through the male line from father to son. It is also occurs at very high levels in Wales and Ireland, pointing to the shared ancestry between these regional populations and the pattern of migration by the Beaker People into the British Isles some 2500 years ago. They originated around Iberia, bringing Celtic culture to the British Isles as well as a knowledge of metalwork, which enabled them to make copper and gold into tools and weaponry, and agricultural skills which gave them a competitive edge over the countries' existing hunter-gatherer inhabitants. These men were believed to have carried a G marker and, while the R1b strand has proliferated all over Europe, the G lineages have almost vanished. The theory is that the G men's reliance on a diet of roots, fruits, berries and meat meant their infants - whose milk teeth would struggle to chew this material - had to be breastfed much longer. This reduced the rate at which the women could bear offspring. In comparison, the R1b lineages were expert at growing cereal crops and knew how to mash dried oats and barley into a nutritious "primitive porridge" which could be spoon-fed to babies, weaning them much earlier. Alistair Moffat, chief executive of Scotland's DNA, said: "Our hypothesis is that those men who carried the R1b lineages came to Scotland and committed what was tantamount to prehistoric genocide. The G lineages have all but disappeared and the R1b groups proliferated like wildfire with fathers having many sons and their sons having sons after them - a geometric progression rather than the population replacement and slow growth of the hunter-gatherer era." Genetic markers refer to errors in copying when DNA is passed down generations: each of us inherits six billion DNA code letters but occasionally small mistakes occur, producing markers. Geneticists can trace these back to the time, place and sometimes the person where they occurred. This means an individual's DNA can be analysed for key markers that offer clues to their ancestry. The new data also helped the scientists working on the project to consolidate a second theory about Scotland's east-west genetic divide, this time revealing peak levels of a key Anglo-Saxon marker in the Lothian and Borders region. This genetic footprint, known as R1b-S21, occurs among 17% of men in south-east Scotland - the same rate found in northern England. It originated in the Rhineland and first arrived in Britain around 400AD. In comparison, only 9% of men in the west of Scotland carry this DNA, roughly the same rate found in Ulster. Researchers were surprised at the extent of the difference between the two regions, which appears to be a throwback to more than a thousand years ago. Moffat said: "The frequency of 17% in south-east Scotland, England North and Yorkshire is a clear memory of the glittering kingdom of Northumbria. Founded in the middle of the sixth century from the great fortress of Bamburgh on the Northumberland coast, it included the Lothians and Borders for four centuries."