SHETLANDERS have overwhelmingly Scottish DNA according to a major research project; one of whose contributors is well-known Orkney geneticist Professor Jim Wilson.
While Shetland is famed for its Viking ancestry, the Edinburgh University research project shows that only 20 per cent of isles DNA is traceable to Norwegian ancestors.
It also shows how much the present day genetic makeup of Scotland owes to Dark Age populations, with surprisingly little shift since then.
Orkney and Shetland are nonetheless the most genetically distinct populations in the whole of Britain and Ireland, but are each other’s closest relatives.
The focus on the Northern Isles used data from individuals from the ORCADES and VIKING studies, previously conducted in Orkney and Shetland respectively.
Wilson said: “In both archipelagos it is incredible how clearly we can tell people apart using their DNA alone, in many cases right down to the level of the isle or parish.”
Within Shetland, Whalsay is the most distinct genetic locality, but differences can be found between the North Isles, North Mainland, West Side, central Shetland and Dunrossness, which is closely linked to Burra and Fair Isle, while there is a grouping between the West and North Mainland.
Shetland is not uniform in the amount of Norse DNA detected. Yell and the West Side are highest at 28 per cent, with Fair Isle and the Central Mainland only 12 per cent.
Orkney is the next most Viking area of the UK, with 18 per cent Norse ancestry, followed by the Western Isles, with nine per cent.
The survey is the largest ever of the genetic landscape of Scotland, and Britain and Ireland more generally, and published in the top journal PNAS.
It is also a time machine back to the genetic makeup of the 19th Century as it used subjects, many born in the 1940s and 50s, whose grandparents were all born in the same parish.
Since then, said Wilson, there will undoubtedly have been a considerable increase in DNA from England and south-west Scotland within the Shetland population.
Scottish ancestry is primarily from the Tayside/Fife area “in accordance with the deep pedigrees of some surnames which are known to originate in that part of Scotland,” said Wilson, followed by Inverness-shire and Aberdeenshire.
Norwegian input is mainly from the western counties of Hordaland and Sogn & Fjordane, with two per cent additionally from Sweden.
Within Scotland, groupings can be broadly assigned to the Borders, the south west, the north east, the Hebrides, Orkney and Shetland, reflecting the regions of yore.
People from Caithness and Sutherland also have a component of Northern Isles blood, possibly from the time that they were ruled by the Jarl of Orkney.
The survey also highlights strong genetic links between Scotland and Ireland and an Irish/Scottish element in Iceland, both factors that are historically well known.
Wilson said that the researchers have been awarded funding to recruit a further 4,000 people of Northern Isles heritage into health studies starting in 2020, and were presently working through the large number of approvals in order to get started.
The research paper The genetic landscape of Scotland and the Isles can be found here: https://www.pnas.org/content/early/2019/08/27/1904761116