The mapping of DNA from some of the settlers who colonised Iceland more than 1,000 years ago offers an insight into the fate of thousands of slaves – mostly women – who were taken by Norse Vikings from Ireland and Scotland before they put down roots on the North Atlantic island.
Anthropologist Sunna Ebenesersdóttir, of the University of Iceland and the company deCODE Genetics in Reykjavik, analysed the genomes of 25 ancient Icelanders whose skeletal remains were found in burial sites across the island.
Sequencing using samples from teeth revealed the settlers had a roughly even split of Norse (from what are today Norway and Sweden) and Gaelic ancestry. It is the first in-depth investigation of how a new population is formed through a genetic process known as “admixture”.
When the researchers compared the ancient genomes to those of modern people in Iceland and other European countries, they found contemporary Icelanders, on average, draw about 70 per cent of their genes from Norse ancestry.
This suggests that in the 1,100 years between settlement and today, the population underwent a surprisingly quick genetic shift in favour of Norse genes, the researchers report in the journal Science.
They confirm that while the ancient settlers, “mainly Norse men and Gaelic women”, are genetically indistinguishable from present-day Irish, Scots and Scandinavians, present-day Icelanders have over the course of 1,000 years, and numerous population bottlenecks, become a distinct new population.
“Repeated famines and epidemics led to a substantial loss of sequence diversity from the Icelandic gene pool, causing it to drift away from its source populations in Scandinavia and the British-Irish Isles,” explained Kári Stefánsson, deCODE chief executive and co-author on the paper.
Another possibility, he suggested, is that ancient Icelanders with more Norse ancestry held a slight edge in reproductive success over those with Gaelic ancestry, many of whom were enslaved when they came to the island.
The Celts were often buried in unmarked graves though, intriguingly, a minority were buried in the traditional Viking way, with their sword and boat.
On the study, he added: “This is a fascinating example of how a population is shaped by its environment, in this case the harsh and marginal conditions of medieval Iceland.
“It is also another demonstration of how our small but well characterised population can continue to make important contributions to understanding the fundamental genetic and evolutionary processes that shape our species.”
Their next step is to expand sample size, and to examine how diseases affected the population.
nodding_and_smiling on July 6th, 2019 at 10:59 UTC »
I was part of the team that performed this analysis. I guess I'm way too late for this to be read by many people, but let me try to clear up some of the misinformation in this article and in the comments:
The title implies that the Vikings took loads of Irish women back to Scandinavia, and all the mixing between them happened there. It sort of suggests that eventually, all Norse people had 50% Irish ancestry. This isn't what the study says. We haven't seen any evidence of Gaelic ancestry in modern-day Norwegians and Swedes, for instance. Instead, it says that of the first generations of people who settled Iceland, we saw on average 43% Gaelic ancestry. Some of these people looked 100% Norse; some looked 100% Gaelic. And yes, some looked mixed – but this mixing could have happened in Viking settlements in the north of Scotland, much closer to Gaelic peoples. When people think of the Vikings – and the comments here are no exception – there often seems to be this idea that all they did was raid and pillage. This did happen, of course, but Vikings also settled and established long-term states in Scotland, Ireland, and other places in Europe. Cultural and genetic mixing happened with their neighbours there, and would have involved much more "boring", peaceful processes than Vikings just "stealing all the women" from other people. We didn't specifically identify the Gaelic ancestry as Irish at all. In fact, identifying where in the British-Irish Isles the Gaelic ancestry came from is a question we're still trying to answer. I imagine that we will find a mix of Scottish and Irish ancestry. It wasn't the case that 100% of the men were Norse, and 100% of the women were Gaelic. By our estimates, it's more like 70% Norse / 30% Gaelic on the male side, and 66% Gaelic / 33% Norse on the female side. It's documented in the sagas that the slaves taken by Vikings included some men as well. The "genetic shift towards Norse ancestry" is complicated, and certainly isn't just a matter of Norse genetic variants magically being "stronger" than others. For instance, Denmark was the colonial overlord of Iceland for much of its history, and we know that some Danish people came to live in Iceland, which is one way of bringing Norse ancestry to the island. It might also be the case that if you were a slave in the early days of Icelandic settlement, or known to be a descendant of a slave, this would have adversely affected your social standing and made it less likely for you to marry and have children. Because the slaves had mostly Gaelic ancestry, this might have caused a shift away from Gaelic ancestry and towards Norse ancestry over time. The "surprisingly quick genetic shift" we found isn't to do with Norse ancestry increasing over time. Instead, it's about Iceland having a small, isolated population that went through population crashes; this "genetic drift" (a technical term) causes big changes in how common genetic variants are in a population, regardless of whether those variants are Norse, Gaelic, West African, or whatever else. If you're a person with Gaelic ancestry, and you take a genetic test that shows you have some Scandinavian ancestry, don't read too much into it. Europeans as a whole are really similar to each other genetically, and it's really difficult to try and identify different kinds of ancestry within them. Whatever specific ancestries you get assigned under European, especially within "Northwest European", are going to reflect a good deal of straight-up noise.In general, if you're not a scientist, I'd advise you to be sceptical about anything you read in the popular press about genetics or medicine. The article in the link is a great example of the fact that journalists usually just don't know enough about science to talk about it well.
Deathshed on July 6th, 2019 at 08:39 UTC »
It's always a little joke in my country of Scotland that the reason there is no good looking people in Scotland is that the Vikings stole them all Haha
Boredguy32 on July 6th, 2019 at 03:12 UTC »
TIL the past was pretty horrific again