THIS MONTH, A new study on Irish DNA provided the very first fine-scale genetic map of the island of Ireland.

For those interested in genealogy, the researchers said that this paper challenges many of the common narratives on the origins of the people of Ireland.

For one, Irish people are, to a large degree, distinctly Irish.

Professor Gianpiero Cavalleri, who helped to devise the study, told TheJournal.ie: “In terms of the genetic diversity for Irish people, there’s actually very little. And the diversity we do see is very subtle.”

The team from the Royal College of Surgeons in Ireland and the Genealogical Society of Ireland found that there were significant gaelic clusters across regions of Ireland.

Source: Nature

These clusters were roughly aligned with the provinces of Ireland, as well as historical events such as the Vikings invasion and the Ulster plantations.

Cavalleri said: “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.

Staying put

Cavalleri said that over the centuries, when you remove emigration, people would largely have stayed within provincial boundaries for much of their lives.

“There were levels of kinship built up over many generations, where marriage patterns were affected by your community,” he said. “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.

To come to these findings, the researchers only examined the DNA of people for whom all eight of their great-grandparents were born within 50km of each other.

“We were very stringent,” Cavalleri said. “But to get to more accurate findings, we wanted to go as far back as possible.”

Overall, they found 10 distinct clusters, or genetic groups, in Ireland.

Seven of these were from gaelic ancestry, and three of them were shared Irish-British ancestry, with the Ulster Plantations in the 17th century having a particular effect on the genetic make-up of that province in particular.

Cavalleri said: “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.

He said that while these kinds of genetic divisions were breaking down over the past century as people began to move around the country more and more, the proof of Ireland’s relative lack of diversity was born out in the DNA.

The Viking influence in Ireland is clear across all of the genetic clusters, Cavalleri said.

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“We see relatively high percentages of the Irish genome have Norwegian ancestry,” he said. “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%.

He said that the further west people go, the less influence they will find in our DNA from other groups.

“It’s what motivated me”

Looking at his own family situation is something that inspired Cavalleri to work on this project in the first place.

Born to Italian parents in Connemara, Co Galway, the geneticist grew up in Spiddal.

“I feel very Irish,” he said. “And I’m really aware of things like people’s roots from living in the west of Ireland. This is partly what motivated me to pursue this in the first place.”

To progress the research and allow the researchers to create a more comprehensive genetic map of Ireland, the team want to hear from you if you fulfill the criteria.

To be eligible, all eight of your great-grandparents must have been born within 50km of each other.

If you fit the bill, you can get involved by contacting irish.dna@familyhistory.ie.