The Dark Age-era kingdoms of Scotland may have disbanded centuries ago but at least in one way they live on – in the people's DNA.
Genetic mapping shows the descendants of Dark Age Scots haven't traveled all that far and are, apparently, living in areas of the countries similar to those of their ancestors. The results of the country's first comprehensive genetic map have been published in Proceedings of the National Academy of Sciences.
"It is remarkable how long the shadows of Scotland’s Dark Age kingdoms are, given the massive increase in movement from the industrial revolution to the modern era," Professor Jim Wilson from the University of Edinburgh, said in a statement
"We believe this is largely due to the majority of people marrying locally and preserving their genetic identity."
The Dark Ages encompasses a large chunk of time from the fall of the Roman Empire (476 CE) to some point circa 1000 CE. During this period, Scotland was split into various kingdoms – Strathclyde in the south-west, Pictland in the north-east, and Gododdin in the south-east, for example – that are largely consistent with six large genetic clusters still present today: the Borders, the south-west, the north-east, the Hebrides, Orkney, and Shetland.
Researchers from the University of Edinburgh and the Royal College of Surgeons in Ireland came to this conclusion after studying the genetics of more than 2,500 Brits and Irish (close to 1,000 of whom were from Scotland) who had grandparents or great-grandparents who were born within 80 kilometers (50 miles) of each other.
While other parts of the British Isles see high levels of Celtic (the west) or Germanic (the east) ancestry, Norwegian ancestry was highest in the north, with residents of Orkney and Shetland showing the highest levels outside of Scandinavia. In Shetland, for example, levels of Norwegian ancestry reached 23 to 28 percent – no doubt the genetic remnants of a series of Viking invasions between the eighth and 11th centuries CE, the Shetland and Orkney Isles off the northern tip of Scotland being the first place the Vikings landed.
The results also suggest that some Icelandic founders may have come from north-west Scotland and Ireland, while people from the Isle of Man appear to be predominantly Scottish in origin. But it's not just a fascinating insight into the history of the country, the researchers say. It could also prove extremely useful from a medical point of view.
"This work is important not only from the historical perspective, but also for helping understand the role of genetic variation in human disease," said Dr Edmund Gilbert from the Royal College of Surgeons.
"Understanding the fine-scale genetic structure of a population helps researchers better separate disease-causing genetic variation from that which occurs naturally in the British and Irish populations, but has little or no impact on disease risk."