Razib Khan One-stop-shopping for all of my content

March 13, 2019

The Insight Show Notes — Season 2, Episode 18: The genetics of the Irish

Filed under: Genetics,Ireland,St. Patrick's Day — Razib Khan @ 3:47 pm

The Insight Show Notes — Season 2, Episode 18: The genetics of the Irish

The Hill of Tara

This week on The Insight (Apple Podcasts, Stitcher and Google Podcasts) we discuss the genetics of the Irish with Dr. Lara Cassidy. She is a researcher at Trinity College, Dublin, in the Bradley laboratory.

Ireland is an interesting nation because the vast majority of people of Irish descent live outside of Ireland due to migration. So the history of his island is more important than the several millions of modern citizens of Ireland would indicate.

Most of the conversation focused on the Holocene. The last 11,650 years, after the Ice Age and the Paleolithic. But the Pleistocene and the Ice Age framed the discussion because it looks like Ireland, like Britain, was probably not inhabited by humans during this period.

When humans did arrive, they were “western hunter-gatherers” of the Mesolithic. About 6,000 years ago the Neolithic, the New Stone Age, arrived in Ireland with farming. Genetics tells us these were very different populations. With the farmers mostly replacing the hunter-gatherers.

Carnac Megalith

Then 4,500 years ago the Beaker people arrived in Britain and Ireland. These people seem to be genetically very similar to modern Irish and brought a unique culture defined by beaker-shaped vessels.

We also discussed controversies such as the timing of the arrival of the Irish language, and the patterns of interaction across the Atlantic facade, of which Ireland was part (which resulted in features such as the spread of Megalith culture to Ireland from the mainland).

In this context, we explored the Cardial and LBK Neolithic cultures, and how they may have spread to Ireland.

The paper Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome is a good overview of the patterns we see in Ireland.


The Insight Show Notes — Season 2, Episode 18: The genetics of the Irish was originally published in Insitome on Medium, where people are continuing the conversation by highlighting and responding to this story.

March 12, 2019

Irish memories faded into myth

Filed under: Genetics,History,Ireland,St. Patrick's Day — Razib Khan @ 1:55 pm
Newgrange Neolithic mound site in Ireland

Located on the northwestern fringe of Europe, on the “edge of the world,” Ireland has occupied a special place in the imagination of the West. It was a mild green land beyond the Roman frontier. But it was also near enough at hand that Irish warlords raided Britain, as Romans such as St. Patrick spread Christianity beyond the frontiers of the Empire. There is no Irish Constantine because Ireland converted gradually in the centuries after the fall of Rome. Western civilization arrived in Ireland on its own terms and took on a very local flavor.

But true history begins before Rome. Just because it wasn’t written doesn’t mean that some memory doesn’t persist down to the present. Unlike other peoples of Northern Europe, the Irish have a rich and detailed mythology recollecting the centuries, and perhaps even millennia, before recorded history. Most famously in the Ulster and Fenian Cycles, which tell the tales of ancient heroes such as Cú Chulainn and Fionn mac Cumhaill. But there is also the Book of Invasions, which tells of the origins of the various peoples which contributed to the Irish of the Iron Age.

Today we have archaeology and ancient DNA to supplement the oral memory of the early Irish. Like much of Northern Europe, during Pleistocene Ireland was uninhabited by humans. It was covered by ice.

Rather, humans only arrived during the Mesolithic, as hunter-gatherers seem to have crossed over from the island of British. Because of the separation of the Irish Sea, this means these people had to take to the open waters and travel by boat. This marine barrier also explains the difference, and more restricted, fauna of Ireland in comparison to Britain (which was connected to mainland Europe via Doggerland).

“Bell Beaker”

Ireland before the Iron Age can be divided into three basic epochs defined by tools and lifestyle. First, the Mesolithic, which marks the settlement of Ireland by hunter-gatherers 10,000 years ago, up until 6,000 years ago. Then, the Neolithic, which brought farming to Ireland. This period spans 6,000 to 4,500 years ago. Finally, there is a 2,000 year period when people who worked in Copper and Bronze were dominant in Ireland, eventually to be replaced by the Iron Age cultures which persisted down to the historical period.

These Copper and Bronze Age people seem to have brought a new pottery technique to much of Western Europe. Because of their utilization of bell-shaped beakers, they are termed the “Beaker people.”

With ancient DNA we have clarified some of the genealogical relationships of these populations. It is almost certain that the Mesolithic hunter-gatherers who arrived in Ireland were related to the famous British “Cheddar Man.” Descendents of Pleistocene hunter-gatherers who spread out across Europe after the “Last Glacial Maximum” from southern refuges, genetically they are very similar from Spain in the south to Britain in the north.

Citation: Cassidy et al., 2012

Before ancient DNA it was possible to suggest that farming spread to Ireland through cultural diffusion from the Middle East. Today that is not a feasible position, as an ancient genome from a Neolithic woman who lived more than 5,000 years tells us that in fact, the farmers were a new people. And interestingly, they were not people from whom the modern Irish descended! Rather, these farmers arrived from Southern Europe, and genetically their closest relatives are the modern populations of Sardinia and Iberia.

Newgrange carving

But these Neolithic farmers were not inconsequential in their impact upon the Irish landscape. They were the great megalith builders across Western Europe, and in Ireland were responsible for memorable sites such as at Newgrange. These mounds and ruins were responsible for the emergence of legends about ‘fairy folk’ who lived underground. The farmers had passed into legend and become a myth, their legacy becoming integrated into the sacred landscape of Ireland, even down into the present.

It is only around 2500 BC, with the arrival of the Beaker folk, that the possible ancestors of the current Irish appear on the scene. Though some of the Neolithic people were likely absorbed into the Beaker people, the five centuries before their arrival in Ireland was one of depopulation, as the ancient farming culture collapsed, to be replaced by pastoralism that did not support the cultural complexity that gave rise of Newgrange. The Beaker people may have arrived in a landscape inhabited by ghosts, and the monuments to their past greatness.

But all this leaves many questions still unanswered.

Were the Beaker people speakers of Celtic dialects which gave rise to Gaelic? Or did these people arrive later, during the Iron Age? What were the contributions of various groups such as the Vikings and the Normans over the past 2,000 years? All of these Northern European populations are quite similar genetically, so it is hard to say.

Only time and better techniques will tell.

Interested in learning where your ancestors came from? Check out Regional Ancestry by Insitome to discover various regional migration stories and more!


Irish memories faded into myth was originally published in Insitome on Medium, where people are continuing the conversation by highlighting and responding to this story.

May 18, 2011

Anglosphere comparisons

The most interesting chart below is infant mortality rate over time.


February 15, 2011

When Histories Collide: The Development and Impact of Individualistic Capitalism

Link to review: When Histories Collide: The Development and Impact of Individualistic Capitalism.

Powered by WordPress

Do NOT follow this link or you will be banned from the site!