Most of the population descended from Celts, Vikings and Ulster Planters
The first genetic map of Ireland has been published as part of a research programme by the Royal College of Surgeons in Ireland.
The team behind the Irish DNA Atlas sought out Irish people who have eight great-grandparents who lived within 50km of one another.
The DNA of the 196 people who were selected, all with four generations of Irish ancestry, was used to create the genetic map. The movements and interrelationships of groups of ancestors can now be traced through DNA, said the research team.
They identified ten genetic groupings, or clusters, that mirrored ancient Irish: Munster divided along northern and southern genetic clusters which coincided with the boundaries of the rival medieval kingdoms of Dál Cais and the Eóganacht.
Genetic signatures from Norse Vikings were found in the Munster, Leinster, Connacht and Ulster.
It found a correlation between the people in the northernmost parts of the island and genetic disorders like multiple sclerosis.
Professor Gianpiero Cavalleri, who directed the research, said the Royal College of Surgeons in Ireland teamed up with the Genealogical Society of Ireland: “They helped us reach the very specific cohort of people needed, people who could demonstrate that all eight of their great-grandparents had been born within 50km of each other.
“This has allowed us to create a genetic map for the Irish population, with resolution similar to that recently drawn for England. While we are delighted by what the study to date has revealed, this is a live study — the more people who participate the greater resolution we can achieve.”
He added: “In terms of the genetic diversity for Irish people, there’s actually very little and the diversity we do see is very subtle.”
Overall, the team found 10 distinct clusters, or genetic groups, in Ireland. Seven of these were of Gaelic ancestry, and three of them of shared Irish-British ancestry, with a large footprint from the 17th century Ulster Plantations
“Broadly speaking, these groups mirror the provinces. What we found in Munster for example is that there’s not one member with Munster ancestry outside of the province. It might be chance, but we don’t think so.
“There were levels of kinship built up over many generations, where marriage patterns were affected by your community.
“These communities were defined by power structures and bases.
“There were two major dynasties in Munster. You probably were not going to marry outside that social structure.
“The largest differentiation we see is between Munster and the rest of Ireland. Then you see Gaelic Ulster, centred around Donegal.
“Then you slowly see more and more groups merging. You have north of Connacht, central Leinster and south of Leinster.
There is also a very pronounced Viking legacy in Irish DNA: We see relatively high percentages of the Irish genome have Norwegian ancestry and specifically from Norwegian coastal areas. We already knew the history of this, but this is now objective scientific fact that there is Viking DNA in Ireland.
“Broadly speaking, Ireland is quite preserved. The Celtic – that is anything that was here before the Vikings – that part of the Irish genome is still around 70 per cent.”
The Irish DNA Atlas team are still accepting donations of DNA and to be eligible, all eight of your great-grandparents must have been born within 50km of each other.
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