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

The red-hair gene is most common in among Scottish and Irish people.

The red-hair gene is most common in among Scottish and Irish people.

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 share 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.

Medieval  map of Ireland, showing Irish tribes.

Medieval map of Ireland, showing Irish tribes.

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 of 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 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 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 in ancient times the sea was one of the fastest and easiest ways to travel. 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 perviously thought. You can read more details here:

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.

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Who Are the Closest Genetic Relatives of the Irish?

Today, people living the north of Spain in the region known as the Basque Country share many DNA traits with the Irish. However, the Irish also share their DNA to a large extent with the people of Britain, especially the Scottish and Welsh.

DNA testing of the male Y chromosome has shown that Irish males have the highest incidence of the R1b haplogroup in Europe. While other parts of Europe have integrated continuous waves of new settlers from the east, Ireland's remote geographical position has meant that the Irish gene-pool has been less susceptible to change. The same genes have been passed down from parents to children for thousands of years. The other region with very high levels of this male chromosome is the Basque region.

This is mirrored in genetic studies which have compared DNA analysis with Irish surnames. Many surnames in Irish are Gaelic surnames, suggesting that the holder of the surname is a descendant of people who lived in Ireland long before the English conquests of the Middle Ages. Men with Gaelic surnames, showed the highest incidences of Haplogroup 1 (or Rb1) gene. This means that those Irish whose ancestors pre-date English conquest of the island are descendants (in the male line) of people who probably migrated west across Europe, as far as Ireland in the north and Spain in the south.

Some scholars even argue that the Iberian peninsula (modern-day Spain and Portugal) was once heavily populated by Celtiberians who spoke at now-extinct Celtic language. They believe some of these people moved northwards along the Atlantic coast bringing Celtic language and culture to Ireland and Britain, as well as France. Although the evidence in not conclusive, the findings on the similarities between Irish and Iberian DNA provides some support for this theory.

However, more recent studies confirm that when a complex picture is taken of Irish DNA, including both male and female lines of descent, the closest similarities are between the Irish and people living in Western Britain. In particular, people in the north of Ireland are close genetic relatives of those living in Western Scotland, probably due to a long history of migration between the two regions.

Read more about National Geographic's 2013 'Genographic' project in the west of Ireland.

The Kingdom of Dalriada c 500 AD is marked in green. Pictish areas marked yellow.

The Kingdom of Dalriada c 500 AD is marked in green. Pictish areas marked yellow.

Irish and British DNA: A Comparison

I live in Northern Ireland and in this small country the differences between the Irish and the British can still seem very important. Blood has been spilt over the question of national identity.

However, research into both British and Irish DNA suggests that people on the two islands have much genetically in common. Males in both islands have a strong predominance of the Haplogroup 1 gene, meaning that most of us in the British Isles are descended from the same stone age settlers.

The main difference is the degree to which later migrations of people to the islands affected the population's DNA. Parts of Ireland (most notably the western seaboard) have been almost untouched by outside genetic influence since early times. Men there with traditional Irish surnames have the highest incidence of the Haplogroup 1 gene - over 99%.

At the same time London, for example, has been a mutli-ethnic city for hundreds of years. Furthermore, England has seen more arrivals of new people from Europe - Anglo-Saxons and Normans - than Ireland. Therefore while the earliest English ancestors were very similar in DNA and culture to the tribes of Ireland, later arrivals to England have created more diversity between the two groups.

Irish and Scottish people share very similar DNA. The obvious similarities of culture, pale skin, tendency to red hair have historically been prescribed to the two people's sharing a common Celtic ancestry. Actually, in my opinion, it seems much more likely that the similarity results from the movement of people from the north of Ireland into Scotland in the centuries 400 - 800 AD. At this time the kingdom of Dalriada, based near Ballymoney in County Antrim extended far into Scotland. The Irish invaders brought Gaelic language and culture, and they also brought their genes.

Irish Characteristics and DNA

The MC1R gene has been identified by researchers as the gene responsible for red hair as well as the accompanying fair skin and tendency towards freckles. According to genetic research, genes for red hair first appeared in human beings about 40,000 to 50,000 years ago.

These genes were then brought to the British Isles by the original settlers, men and women who would have been relatively tall, with little body fat, athletic, fair-skinned and who would have had red hair. So red-heads may well be descended from the earliest ancestors of the Irish and British.

Who Are the "Black Irish"?

The origin of the term "Black Irish" and the people it describes are debated (see the comments below!). The phrase is ambiguous and is mainly used outside of Ireland to describe dark-haired people of Irish origin.

The ambiguity comes in when trying to determine whether dark-haired Irish people are genetically distinct from Irish with lighter coloring. Dark hair is common in Ireland, while dark complexions are more rare.

One theory about the origins of the term is that it describes Irish people who descend from survivors of the Spanish Armada. There are other hypotheses, mostly placing Irish ancestors on the Iberian peninsula or among the traders that sailed back and forth between Spain, North Africa, and Ireland, particularly around the Connemara region.

Some "Black Irish" are of Irish-African descent, tracing their ancestry back to the slave trade. Many of these people live on Barbados and Montserrat.

Some readers, writing below, with typical Black Irish coloring have had genetic testing done to confirm that they have Spanish, Portuguese, and Canary Island heritage.

Read more about the origins of the people of Ireland

Click on a title to read more about the history of the Irish people:


CatClark on May 01, 2018:

This is a fascinating subject. As stated in my earlier comment here, I visited Northern Spain recently and saw at least 3 doubles. I'm Irish, hailing from Tipperary, and Ryan is my maiden name. My father had red hair. If the woman in the photograph that accompanies this article had dark hair and a widow's peak, she would be me in an earlier decade. Everyone wants to know where they came from. We are creatures of the past. Every thought and instinct, hope and wish we have is a product of our genes and history interacting with the present.

Israel Putnam on October 30, 2017:

Just received the results of DNA testing. My mother was all Irish, and referred to herself as “Black Irish,” having black hair and brown eyes; traits that I carry as well. Testing revealed 60% “Irish, Scottish, and Welsh” heritage.

Oddly enough, I have carried a very Eastern European type last name through my life. Turns out, I have only a 1% portion of my DNA from Eastern Europe—and an equal amount of “Iberian.”

Essentially, I’m 60% Irish and 38% English.

Nell Rose from England on October 01, 2017:

its funny really because the only true Celtic people in the UK are the English and Welsh! The Scots and Irish are actually Gaelic, the English is the most Celtic, you only have to know about Boudicca the biggest and most famous Celtic queen of the lot! if you look at the English Celts there are at least 20 tribes just in England, not Scotland or Irish! It does make me laugh when they say they are Celts, they are gaelic, doesn't roll off the tongue so easily does it? interesting stuff.

QueenMay on September 28, 2017:

Hi, I just wanted to say your article is very interesting. I did DNA got 97% Irish which I think is a high number, 2 % Finland, 1% Native American. Iberian was mentioned on my pg. Now I think the Spanish blood that my Mother talked about must of come from there. I knew of Irish and American India as well . Well one part said 2 %Europe but then it said Finland. Anyway just was so happy 97% Irish.

J-Ryan on August 04, 2017:

Good read! My family has always talked about 'Black-Irish'. Both my dad and my wife's dad had jet-black hair in their youth (my aunts and uncles included). Obviously Irish (Ryan and O'Brien) and traced back to Tipp and Limerick. Both fathers had genetic testing done recently and they both have DNA matches from Ireland and Spain.

Kathy Wigley on July 26, 2017:

I am working on my family genealogy and DNA testing family members. My Dad is a Matlock/Medlock ancestry whose Y-DNA is R1b1b2 (R-M269). My Mother is an Owens and her mother is a Ruggles. The Ruggles line is R1b1b2 (R-M269) and her Dad's mother's paternal line is Howe (R1b1b2 (R-M269). Mom's father is an Owens (J2a3-L26). Through my parents I inherited the Rh- blood factor while my siblings did not. My Mom is AB + and I am B-. My siblings are B+. My paternal aunt said my dad was O+. I learned that in order for me to be Rh-, both my parents had to carry rh+/rh- alleles in order for me to inherit the Rh- blood type. I also make it a point to search for the haplogroups of my ancestors so I can learn more about my ethnicities I inherited from them. From both my parents I have the Irish. has allowed me to compare my DNA against my Mother's so I could learn what I didn't get from her and what part of I got from my Dad, like his African, Middle Eastern and Native American.

Daena from Arizona on July 04, 2017:

I just had a DNA test done and I was shocked to find out that I had 13% Iberian Peninsula but only 11% Ireland even though my 3rd great grandmother was born in Ireland. This is a really interesting article and brings about a few "aha" and "oh?" moments!

Larry Freitas on June 20, 2017:

Heidi: Yes, the idea that enough Spaniards survived shipwrecks during the Armada by swimming ashore in Ireland's west coast to have left a sizable genetic marker there has been debunked. That 'Mediterranean' look already existed there for many thousands of years. That doesn't mean that various European people haven't migrated to Ireland in more recent centuries either, as has happened in Britain, but those immigrants would have moved to the bigger cities, such as London, Dublin, Edinburgh, and Cardiff. Then there are those Irish emigres to Britain. I have friends who live in the Cotswolds in England, and they are from Wales originally, but really only the wife of this couple. The husband is actually Irish, as his grandfather moved to Wales for work in the early 1900's. He does consider himself Welsh, though he never learned to speak it growing up near Swansea. His wife does know how to speak it. Wales was once a hub of industrial activity, and it attracted other British and Irish as well as people from other parts of Europe for the jobs available in the steel works and coal mines back a century ago. But go to those old coal valleys like the Rhondda and everyone is really Welsh and it's been like that for thousands of years, not unlike rural Ireland where everyone is really Irish.

In Cornwall, the Cornish have little genetic evidence of invaders and outsiders, as the Romans and then Anglo/Saxons, and later the Normans, basically left the place alone, nominally controlling that area. Since 2014 the Cornish have been designated a separate ethnicity in England.

The Basques were barely affected genetically by Roman, Germanic, or Moorish invaders. In fact of those three invading groups, only the Moors had much of a genetic effect on the Iberians as a whole. The DNA of Basques suggest that they are descendants of an admixture of people who had been living there since the end of the Ice Age or before then with later comers, Indo-European speakers and R1B1 carriers, who came into the region during the late Stone Age and through the Bronze Age, but the ancient language held and a Centum Indo-European language, what would have become a proto-Celtic language, never caught on there. So proto Celtic and later Celtic languages were spoken in the Iberian peninsula eventually, but not in the Basque region, as it was a matriarchy, and the mothers kept the old language and customs alive. The area was isolated enough that the blood types of Basques are quite different from other nearby Spaniards and French, even if the R1B1 DNA exists in them as it does throughout Western Europe, and it just happens that the Basques have high concentrations of that DNA as do the Irish, Welsh, and Cornish, though some isolated areas of Galicia in Spain and Northern Portugal have the same. Pay de Basque, or Pais Vasco is also one of those areas where the invaders' language was affected by those they invaded, instead of the other way around. Think of France: Germanic-speaking Franks took up a pre-French Latin to speak as the Roman Empire was falling, eventually which developed as the French language. Old Barbarian German was lost there. The Franks left their name on the new nation, but not the language the spoke.

So, if taking into account that an admixture of more ancient people with newcomers during the late Neolithic and Bronze Ages accounted for Basques and Irish to have similar DNA, it does not make the Basques "Celts." If it means some Irish look like some Basques, that has more to do with what happened in Western Europe some 5,000 years ago to anything that has happened in much more recent times.

HeidiWoods on June 18, 2017:

We had an old family legend that could never be confirmed. The legend was that we were "Black Irish" and that we were descended from the survivors of the Spanish Armada. But when I did some research, it seemed unlikely that there would be such a great population of "Black Irish" in such a relatively short amount of time.

My mother's maternal grandmother was from Dublin. But two things stood against delving into her line of the genealogy. 1 - she wasn't an Irish Catholic who married a Scottish Protestant, so both families disowned them. And, 2 - the records department in Dublin burned down, so we didn't know where else's to look for records. Well, my siblings and I bough the a 23andme kit for my mum for Christmas this last year.

Mum has just gotten her results, and because the DNA follows the maternal line, we have confirmation that we come from the Basques!! From some of my reading, I kind of already had a feeling. My mum and sisters are rh negative, and that was another clue for me, as the Basque have a higher percentage of this than other populations. This is super exciting for us and solves a bit of a mystery. Also, my mum has connected with some Irish "cousins" that my husband, daughter, and I will hopefully be able to meet with when we go to Ireland in 3 weeks!

Larry Freitas on June 18, 2017:

I visited Cornwall in March of 2017 and was told that black hair is quite common there. That got me into doing a bit of research when I got back to California, and found this R1B1 map of Europe, and that that DNA is very prominent if one from Ireland, Britain (England, Scotland, Wales, Cornwall, Isle of Man), Belgium, France, southern Germany, Switzerland, northern 2/3rds of Italy (but not Sicily or the south), Sardinia, Minorca and Majorca, Spain, and Portugal. That DNA has a very high representation in a few places in particular: Ireland, Wales, and the Basque region with highest percentages overall. It is a paternal DNA as well. It was carried into Europe from Western Asia and Eastern Europe starting in the late Neolithic Age and into the Bronze Age. Centum Indo-European languages then developed in the following millennia: Italic, Celtic, and Greek, but the Greeks weren't R1B1 DNA carriers. So proto Celtic languages started in those areas with R1B1, as well as Italic. Lusitanians in Iberia might have spoken a language more related to Italic than Celtic, but most of the tribes in Iberia were speaking a Celtic language that became extinct during the two centuries that Rome took to conquer, with 19BC being the year ancient Galicia (Austurias, Cantabria, Leon, Galicia and the northern 1/3rd of Portugal) fell. Celtic is a culture and language group, not a genetic one. Obviously if R1B1 was and is a paternal line, so that means there's a maternal one as well, and geneticists believe that some of that DNA came from people who left north Africa after the last Ice Age, as the Sahara region really heated up, and people there fled into southern Europe and further north. Now obviously there were other people already in Europe, so there would have been an admixture then, some 10,000-15,000 years ago, followed around the time 3,000-7,000 years ago of Indo-European speakers flooding into Europe, causing even more admixtures of people. So, even if R1B1 is quite dominant in Ireland, Wales, and the Basque region, it doesn't mean that those people share anything like the exact same DNA. Quite the opposite. Maternal North African DNA is also prominent in the Iberian Peninsula, and much less so further north to where it barely registers in Britain and Ireland. Iberia also had coastal areas in which Phoenicians, Carthaginians, and Greeks settled. Compound that with the fact that there was the Muslim invasion of Iberia, with another influx in 700-800 of northern African people (Moors in Iberia, Saracens in the case of Sardinia, Sicily and southern Italy). Then there's the fact that those with Nordic DNA invaded Britain and Ireland, the Angles and Saxons in the 5th and 6th centuries, and a few centuries later the Danes and Vikings in both Britain and Ireland, and northern France as well, leaving some genetic markers with the invaded. When the Roman Empire fell, in the 400's, Nordic-type Germanic barbarians invaded the Iberian Peninsula as well, the Suebi and Visigoths in particular, though they didn't leave much of a genetic marker. The Romans and Italic peoples (and some northern Italic people had Celtic roots), however, also did not genetically influence Britain much, or Iberia, but did ancient Gaul (France) to a greater extent, and Ireland not at all because it wasn't in the Roman Empire. It's also true that Britain during the time of the Roman occupation, 50-410, imported legions, some that were made up of people from the eastern regions of the Empire, like Sarmatians and Alans, people related to Iranians by language, who were from the area of the Caspian Sea and Black Sea. It's thought that 5,000 Sarmatians settled in Britain in the Roman villas and outposts. There is now some historical evidence that the 'historic' King Arthur could have had Sarmatian, not Briton or Romano-British, roots!; and I heard that from an Arthurian scholar who lives in Tintangel in Cornwall.

Now, why didn't the Basques lose their language circa 3,000 BC, and therefore become Celtic speakers? That area apparently had a matriarchal society, and Indo-European invaders, carriers of R1B1, who assimilated with the Basques had children who learned the language and culture of their mothers. So, they kept a much older language, which might have been spoken, or at least variations of it, throughout much of Western Europe, before Indo-European Centum languages became dominant in the area; in other words from the time of the Ice Age into the late Stone/Neolithic and early Bronze Age.

If I could bring back Cornwall into my discussion, I visited Tintangel and saw the bi-lingual English/Cornish signs. One of the docents told me her mother had black hair, and that no one really knows how to pronounce Cornish, and that Welsh is used as a base to do so, as it is assumed Cornish sounded like Welsh.

Regarding the Black Irish, not many Spanish sailors and soldiers who got ship-wrecked during the Armada survived. Few, very few, ended up in Ireland. Some were handed over to the English for money. Some made it to France and then back home. Most of them died, drowned, or if they made it to shore died soon thereafter. What is true is that the island of Valentia off the south coast of Ireland became a refuge for sailors who shipwrecked there, some who were Spanish, but of other nations as well. What is also true is that the west of Ireland had been designated in the late 19th century by scholars such as H.G. Wells, as a place where the "Mediterranean" type of Caucasian existed: dark hair, dark eyes, and olive skin, though pale olive. And Ireland wouldn't be the only place where that type existed in Britain or Ireland. So, former Ireland rugby internationals Michael Bradley and Tony Ward (who I was once mistaken for) have dark hair and eyes, and the olive complexion. So does the Welsh Catherine Zeta-Jones and Tom Jones, and then there was the English Cary Grant and James Mason, and let's not forget Scot Sean Connery. I've also visited Galicia some time ago. There are plenty of blond and red-haired, though it's usually auburn, to be seen walking around the streets of Santiago de Compostela or Noia, or Vigo for that matter, along with the usual suspect "Mediterranean" type. You could see them in northern Portugal as well, such as in Guimaraes, but less so in Oporto.