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The genomics of the Viking Age

A huge new preprint on Vikings (as well as the Bronze Age, Iron Age, and comparisons to moderns), Population genomics of the Viking world:

…we sequenced the genomes of 442 ancient humans from across Europe and Greenland ranging from the Bronze Age (c. 2400 BC) to the early modern period (c. 1600 CE), with particular emphasis on the Viking Age. We find that the period preceding the Viking Age was accompanied by foreign gene flow into Scandinavia from the south and east: spreading from Denmark and eastern Sweden to the rest of Scandinavia. Despite the close linguistic similarities of modern Scandinavian languages, we observe genetic structure within Scandinavia, suggesting that regional population differences were already present 1,000 years ago. We find evidence for a majority of Danish Viking presence in England, Swedish Viking presence in the Baltic, and Norwegian Viking presence in Ireland, Iceland, and Greenland. Additionally, we see substantial foreign European ancestry entering Scandinavia during the Viking Age. We also find that several of the members of the only archaeologically well-attested Viking expedition were close family members. By comparing Viking Scandinavian genomes with present-day Scandinavian genomes, we find that pigmentation-associated loci have undergone strong population differentiation during the last millennia. Finally, we are able to trace the allele frequency dynamics of positively selected loci with unprecedented detail, including the lactase persistence allele and various alleles associated with the immune response. We conclude that the Viking diaspora was characterized by substantial foreign engagement: distinct Viking populations influenced the genomic makeup of different regions of Europe, while Scandinavia also experienced increased contact with the rest of the continent.

A few notes:

– Though the broad patterns seem to have been established with the expansion between 3,000 and 2,500 BC from the Yamnaya steppe (at least in Northern Europe), some subtle details in genome-wide ancestry shifted in subsequent periods. This data set seems to show a decline in “Neolithic Farmer” and increase in hunter-gatherer and steppe ancestry after the Bronze Age, with some increase in the former by the Viking Age. This suggests that there is some sort of skew in sampling which misses populations enriched for hunter-gatherer ancestry (I suspect these groups live in the most marginal land and are the most mobile).

– There is structure by the Viking Age, which is not surprising. But the authors also report a few regions of southern Sweden where samples are enriched for Neolithic farmer ancestry down to the Viking age, suggesting that even ancient structure wasn’t well mixed (yet).

– Most of the selection for the phenotype which characterizes modern-day Northern European populations seem to have completed over the 2,000 years between the Bronze Age and the Viking Age.

7 thoughts on “The genomics of the Viking Age

  1. FWIW, there are only two samples prior to 70 CE in the 442 person sample, a Danish woman and a man from Norway, both from the early Nordic Bronze Age (one from 2400 BCE and the other from 1800 BCE), so the abstract provides a bit of false hope regarding the breadth of its sample. This is not enough of a sample to reach much in the way of conclusions, even from autosomal genetics where much smaller sample sizes are acceptable, particular because even in the Bronze Age the people of this region had considerable long distance maritime mobility, and also because significant population structure was still present in these peoples in much later time periods.

    The geographic diversity of the sample, in contrast, is greater than one might naively expect, including, for example, Viking remains from Italy and Estonia.

  2. A lot to fully take in but with regard to the Karda group in particular, I have to wonder a bit about their conclusions. Compared to the Danish LNBA sample they use in their comparison, it shows much more Barcin-related and less Loschbour-related ancestry, which would imply overall further admixture (keeping in mind the various back-and-forths the data show from the BA to the VA) via a very HG-poor farmer source quite unlike what we see in Northern Europe at the time, and unlike the Danish LNBA group, it can’t be modelled well without CHG or Armenia_MLBA as a fourth source, more than what’s required for the Southern Italian Foggia group even.

    Is it really a super-isolated group that somehow harkens back to the LN/EBA (but with even more Barcin-related ancestry!) rather than one that has some sort of even Southeastern European or West Asian related ancestry? What are people’s thoughts on that?

    In general the higher Barcin-related increase in southern Sweden seems to speak to greater relative cosmopolitanism and interaction with more continental (aside from the HG-heavier Baltic) regions than very old resurfacing, at least at first glance.

    It’s nice to see the eastern European Swedish affinities that seemed to come up with other methods (modern Swedes taking a decent amount of Baltic_BA-related ancestry and pulling very clearly towards eastern Europeans relative to other Scandinavians in intra northern European PCA with the Eurogenes tools for example) detected in the preprint as well, ditto with the subtler Atlantic-like ancestry in Norwegians (the Icelanders were already partially covered in that previous paper) about which I had the impression of being more “Northwestern European” in affinities within Northern Europe than some of the ancient post-Corded/Beaker Scandinavian genomes. Though I feel the latter situation is harder to disentangle than the former.

  3. It’s a great paper and entirely agrees with my observations and predictions from years ago.

    About 15 years ago, I predicted that “Vikings” who raided Ireland were probably a mix of Scandinavian and Celtic men, as we know from Irish history that Irish Vikings spoke Irish Gaelic and in many customs appeared Gaelic. I also predicted that some Y-Haplogroups seem to have expanded and spread with “Vikings”, even though their origin seemed Non-Viking. This is particularly true about my own clade of R1b-L21-M222-FGC458 – or the “Conroy-Dunne” Cluster. The original name O’Duinn is attested from at least 1,100 AD in NW Laois, with a legend that they came from the Meath/Dublin area. Conroy In Laois is a branch of O’Duinn from after 1577 AD. Yet there are Norman “Dalton” men who are close matches. I predicted then that the Dublin Vikings absorbed local Gaelic men in Dublin/Meath, who became fully fledged Vikings. Later, during the colonization of Normandy, the Dublin Vikings were given exclusive rights to the Cotentin Peninsula, which they settled. I suggested that some of these Cotentin peninsula Vikings must have carried FFC458 and returned as Daltons.

    Interestingly, it was Normans from the Cotentin peninsula that went as mercenaries to Byzantium, were stationed in Southern Italy and decided to take it over. They then conquered Sicily too. By a strange coincidence my wife’s Sicilian grandmother from Palermo has Irish relatives in the Irish Midlands in County Laois, a few of whom are 3rd cousins of my father.

    These same Norman Sicilians went on to conquer the “County of Antioch” in today’s Syria/Lebanon, and my father has some distant Assyrian relatives.

  4. Another interesting thing is that my father has now about 100 Norwegian relatives in Norway, and after US, UK, Ireland, Australia and New Zealand, Norway is his 6th most relatives by country. He also suffers from “Viking Hand”. He has most relatives in Rogaland, Norway, then on the Norwegian/Swedish border area, and thirdly in the far North In Tromso. The paper says some of the Northern Norwegian Vikings were 100% Saami/Finns, and MyHeritage estimates that my father is 7.5% Finnish.

    Meanwhile my mother has many Danish relatives from the island of Funen, and some in Iceland, while her 2nd cousin in Laois, carries mtDNA U5b1b, which is usually considered Saami.

  5. Does anyone know whatever happened to the research project into Viking DNA in the Cotentin Peninsula which was a joint effort between Leicester University and a French institution whose name I have forgotten?I know there were protests in France against permission being granted and suspect it may have been closed down. At any rate no results appear to have been published. There was a leak to the effect that M222 had been found in some old families, but it was not any of the common Irish/Scottish subclades.

  6. @michael, very interesting, as M222 breaks down into 4 subclades, with only one widespread across Ireland and Scotland and probably representing the Ui Neill and allies. I belong to one which is mostly confined to South Central Ireland, especially Laois and to a lesser extent, Kildare and Carlow, adjoining counties. However my clade is the only one which includes Non-Irish/Scottish names, with Norman and English (Dryden) names.

  7. Here’s two tourist magazine summaries of recent archaeological digs and associated speculations in Iceland:

    https://icelandmag.is/article/new-archaeological-research-forces-historians-reconsider-story-icelands-settlement

    https://now.guidetoiceland.is/2019/02/12/culture/history-and-folklore/not-only-vikings-new-archaeology-find-sheds-light-on-icelands-first-settlers/

    Academic papers here:
    https://www.researchgate.net/profile/Bjarni_Einarsson
    ?

    Maybe you can find more academic papers by him and The Archaeological Office of the Iceland. The Saami-hypothesis is interesting.

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