Blood of the Irish: What DNA Tells Us About the Ancestry of People in Ireland

Blood of the Irish

The blood in Irish veins is Celtic, right? Well, not exactly. Although the history that used to be taught at school said the Irish were a Celtic people who had migrated from central Europe, the latest studies of Irish DNA tell us a very different story.

Research done into the DNA of the Irish has shown that our old understanding of where the population of Ireland originated may have been misguided. The modern Irish population shares many genetic similarities with Scottish and Welsh populations and, to a lesser extent, the English. At the same time, DNA testing of remains of ancient Irish people suggests that some of the earliest human arrivals on the island originally came from much further afield.

This article is based on the research available in early 2018—however, new discoveries are being published regularly, so if you want to keep up-to-date on this topic, make sure you check online scientific journals such as Nature.

Early Origins of Irish DNA

The earliest settlers came to Ireland during the Stone Age around 10,000 years ago. There are still remnants of their presence scattered across the island. Mountsandel in Coleraine in the North of Ireland is the oldest known site of settlement in Ireland—remains of woven huts, stone tools and food such as berries and hazelnuts were discovered at the site in 1972.

Where Did the Early Irish Come From?

For a long time, the myth of Irish history has been that the Irish are Celts. Many people still refer to Irish, Scottish, and Welsh as Celtic culture. The assumption has been that they were Celts who migrated from central Europe around 500BCE.

Keltoi was the name given by the Ancient Greeks to a 'barbaric' (in their eyes) people who lived to the north of them in central Europe. While early Irish art shows some similarities in style to central European art of the Keltoi, historians have also recognized many significant differences between the two cultures.

Recent research into Irish DNA at the beginning of the twenty-first century suggests that the early inhabitants of Ireland were not directly descended from the Keltoi of central Europe. Genome sequencing performed on remains of early settlers in Ireland by researchers at Trinity University in Dublin and Queens University has revealed at least two waves of migration to the island in past millennia. Analysis of the remains of a 5,200-year-old Irish farmer suggested that the population of Ireland at that time was closely genetically related to the modern-day populations of southern Europe, especially Spain and Sardinia. Her ancestors, however, originally migrated from the Middle East, the cradle of agriculture.

Meanwhile, the research team also examined the remains of three 4,000-year-old men from the Bronze Age and revealed that another wave of migration to Ireland had taken place, this time from the edges of Eastern Europe. One-third of their ancestry came from the Steppe region of Russia and Ukraine, so their ancestors must have gradually spread west across Europe. These remains, found on Rathlin Island, also shared a close genetic affinity with the Scottish, Welsh, and modern Irish, unlike the earlier farmer. This suggests that many people living in Ireland today have genetic links to people who were living on the island at least 4,000 years ago.

Do Irish Origin Myths Match the Scientific Evidence?

One of the oldest texts composed in Ireland is the Leabhar Gabhla, the Book of Invasions. It tells a semi-mythical history of the waves of people who settled in Ireland in the earliest times. It says the first settlers to arrive in Ireland were a small dark people called the Fir Bolg, followed by a magical super-race called the Tuatha de Danaan (the people of the goddess Dana).

Most interestingly, the book says that the group which then came to Ireland and fully established itself as rulers of the island were the Milesians—the sons of Mil, a soldier from Spain. Modern DNA research into male Y chromosomes has found that the R1b haplogroup reaches very high concentrations in Western Ireland and the Basque country in northern Spain. While the picture for matrilineal descent (mother to daughter) is more complex, it seems that the northern Spanish and the Irish might have common male ancestors at some point in history.

There are also interesting cultural similarities along the western seaboard of Europe, stretching from Spain up to Ireland—as has been written about by the archeologist Barry Cunliffe. Although it might seem surprising, it is worth remembering that the sea was one of the fastest and easiest ways to travel in ancient times. When the land was covered in thick forest, coastal settlements were common and people travelled around the seaboard of Europe quite freely.

Another interesting finding about Irish DNA is that many men in North West Ireland (and their descendants around the world, including about 2% of men in New York today) are descended from a single man who lived in Ireland around 1600-1700 years ago. This coincides with the time of the famous Irish king Niall of the Nine Hostages, who legend says brought St Patrick to Ireland as a slave. The O'Neill family, who claim to descend from Niall, have certainly been a powerful family through the ages in Ireland.

Meanwhile, the latest research in 2018 suggests that the Irish are most closely related to people in North West France (Brittany where a Celtic language has traditionally been spoken) and in Western Norway. Interestingly, where earlier studies didn't find much impact of Viking DNA among the modern Irish, a recent study suggests there may have been more influence than previously thought.

What we can take from all of this is that, although the Irish today feel part of a single group united by cultural and national identity, this culture and identity is ultimately founded on waves of migration connecting the island to the wider world of European peoples and beyond.