Thrall’s Saga

There’s a new paper out on Iceland’s demography. Originally, Iceland was roughly half Scandihoovian and half bog-trotters. But today, the islanders are about 70% Norse.

The authors think that this was probably genetic drift. They are wrong.  Those Gaelic ancestors came in as thralls: they didn’t own land.  Iceland was a tough place to survive in: landowners did better.

This should be obvious, particularly since the authors are themselves Icelandic. Perhaps they are not descendants of Aud the Deep-Minded (Ketilsdottir).


Correction: I foolishly believed the short description by Michael Price, rather than reading the whole article, which is behind a paywall. Price misunderstood the article: the authors do not think that the shift towards Scand was caused by drift, but rather by reduced opportunities for slaves – perfectly sensible.


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40 Responses to Thrall’s Saga

  1. Paul Conroy says:

    The more surprising take away, is that they suggest that drift alone has moved the Icelandic population away from both the Norse and Irish sources, as they state that Ancient Icelanders were similar to today’s Irish or Norse.

    Meanwhile the graph clearly shows that 5 Ancient Icelanders were fairly close to today’s Icelanders?!

    This they explain as these 5 Icelanders must have had an outsized impact on the overall population – like the Byerley Turk and Co had on Thoroughbreds:

    This seems likely, but doesn’t explain why they themselves were outside the range of modern Irish or Norse??

    My prediction is that they contained a small fraction of some other admixture, not covered in there control samples, such as Dorset or Pre-Dorset from the Americas, or some remote Atlantic island distinct ancestry, say Shetland or Aran.

    • Anonymous says:

      It’s just genetic drift. There’s nothing exotic to be found there. A single Icelandic family has some exotic maternal line remotely linked to Native Americans, but such were also found in Karelian Hunter-Gatherers that lived 8000 years ago.

      • Paul Conroy says:

        “It’s just genetic drift”

        You can only demonstrate this if you have a full array of possible ancient admixture samples, like the Saqqaq and Clovis sample, plus the 3x Rathlin Island and so on.

        In the coming weeks, once the data becomes available and uploaded to GEDMatch and elsewhere, and run through admixture calculators, we’ll see if it’s just drift.

        • gcochran9 says:

          A reasonable person, or even me, would have strongly suspected that the thralls under-reproduced the landowners before any measurements had even been made.

          • Paul Conroy says:

            Duh, obviously!

          • Paul Conroy says:

            I’m addressing the “interesting” issue, as I outlined above, not the obvious one.

            Going back to my thoroughbred example, 3 Arab stallions are supposed to account for the major inheritance of all thoroughbreds today, and they do. But what makes thoroughbreds unique is their speed, and where did this quick twitch gene come from, that sets them apart?
            It did not come from the Arab sires, but from native ponies of the Irish & British Isles! They’ve found it today in Shetland and Exmoor ponies, populations with no thoroughbred admixture at all.

            Is that what’s going on in Iceland too, possibly.

          • Frau Katze says:

            I was under the impression the Irish were women. So men came too? Did the Norse bring any Norse women?

            • Ruritanian says:

              Unn the Deep Minded was one of the more famous of the early settlers of Iceland, and she was a woman, so yes.

              There’s an older paper that says:
              “we obtained an estimate of 58% ancestry from Scotland and Ireland for contemporary Icelanders (95% C.I.: 44.6–71.2%). In comparison, the IEMS [DP: Iceland Early Medieval Sample] yielded an estimate of 64.7% (95% C.I.: 36.8–90.3%), indicating a similar excess of matrilineal ancestry from Scotland and Ireland.”

              Those are really large confidence intervals, though.

            • Frau Katze says:

              @Ruritanian Yes I realize now that it’s a lot less simple than I thought.

    • Halvorson says:

      The five samples in question show a very weak drift toward today’s Icelanders. The fig. 2 ADMIXTURE run classifies them as nearly entirely Norse and DAV-9 was actually raised in Norway. His drift cannot be explained by mixing with Eskimos or Martians.

      It’s not a coincidence that these 5 samples represent 5/8 of the most ancestrally Norwegian skeletons sampled here.

  2. pyrrhus says:

    The modern scientist averts his gaze from the horrors of the past, especially events like mass starvation…

  3. Huh? says:

    Cochran: The authors think that this was probably genetic drift. They are wrong. Those Gaelic ancestors came in as thralls: they didn’t own land. Iceland was a tough place to survive in: landowners did better.

    Cochran, the authors specifically said this was not the case, that is was not drift. Khan even retweeted the part of the paper where they specifically said that –

    “This observation raises the possibility that reproductive success among the earliest Icelanders was stratified by ancestry, as genetic drift is unlikely to systematically alter ancestry at thousands of independent loci. We note that many settlers of Gaelic ancestry came to Iceland as slaves, whose survival and freedom to reproduce is likely to have been constrained”

    They even identified specific samples they believed contributed disproportionately to present day Icelanders, so they certainly do not believe in equal likelihood of reproduction among settlers.

  4. MEH 0910 says:

    “60 Minutes” in Iceland 1976 and a little more

    • mapman says:

      Lots of things changed since 1976. There are now ~10% of Poles in Iceland and a small but very visible minority is Middle Eastern. A lot of elderly will probably never recover from the 2009 financial collapse. And yes, dogs are now legal in the cities.

  5. dearieme says:

    As far as is known, the original population of Iceland consisted of monks, presumably from Ireland or Scotland. If they were good monks there will be no trace of them in the genetics, of course. Especially since they seem to have left in a huff. Unless that’s just propaganda cover for “we killed the lot of ’em!”

    • Smithie says:

      I don’t know what the potential chronology would be, but it does seem sort of hard to believe, unless there was an eruption, or severe period of cold. I mean, if there were Irish priests or monks, surely there would have been other Irish people.

      Skellig Michael had a monastic community on it, but that was basically just a rock. Iceland probably would have been considered good, fertile land compared to some of the more marginal places in Ireland. I’ve hear tales of cows that were so starved that they had trouble rising to their feet, and they needed to be pushed.

    • Paul Conroy says:

      The monks who discovered Iceland and documented it – see Dicuil – were Gaelic, mostly from Ireland and some from its colony of Scotland.

      • dearieme says:

        Yes, people are strangely quiet about the Irish years as an imperial, conquering, colonising people.

  6. Smithie says:

    I wonder what happened in Ireland. Why do the Norse paternal haplogroups not seem to show up at significant levels? Were there not many Norse men to begin with? Did they leave, or is it something else?

    • Paul Conroy says:

      Part of the solution to this problem is who gets labeled a Viking. The simplistic notion is that Vikings were Scandinavians, but in fact we know that many Vikings were substantially Irish or entirely Irish, and they certainly assimilated to Gaelic society, speaking Gaelic and following Gaelic customs.

      A Viking was more like being a Pirate and they picked up recruits wherever they went, either voluntarily or coerced.

    • Bob says:

      The Vikings, like the Normans and English, tended to live in towns and villages in Ireland, while the native Irish lived in the rural areas. The towns and villages were more densely populated and thus suffered more from plagues and were probably demographic sinks compared to rural Ireland.

      Hiberno-Norman Kilkenny presence in Kilkenny was deeply shaken by the Black Death, which arrived in Kilkenny in 1348. Because most of the English and Norman inhabitants of Kilkenny lived in towns and villages, the plague hit them far harder than it did the native Irish, who lived in more dispersed rural settlements.

      A celebrated account from a monastery in Cill Chainnigh (Kilkenny), by Friar John Clyn in 1348 chronicles the plague as the beginning of the extinction of humanity and the end of the world.
      “ The pestilence gathered strength in Kilkenny during Lent, for between Christmas day and 6 March, eight Friars Preachers died. There was scarcely a house in which only one died but commonly man and wife with their children and family going one way, namely, crossing to death.[13] ”

      The plague was a catastrophe for the English habitations around the country and, after it had passed, Gaelic Irish language and customs came to dominate the country again. The English-controlled area shrunk back to the Pale, a fortified area around Dublin.

  7. Paul Conroy says:

    I wonder is there positive selection on FADS2 in the modern Icelandic population? The original Irish and later Norse settlers would have had the usual Northern European diet, high in dairy and fish.
    But Iceland has been subject to boom and bust population cycles and possibly other sources of food, like sea mammals were utilized substantially in bust cycles of famine.
    They probably absorbed the Greenland Viking population too, which may have had Skraeling or even Inuit ancestry.

    Another possible area under positive selection would be verbal IQ. The Scandinavians generally don’t write and few sagas come from there, but the Irish source population would have had many writers (monks etc) and had a higher verbal IQ and been highly literate. I’d expect saga writers and storytellers would have enhanced fitness, in such an environment.

    • Bob says:

      Did the Irish used to eat a lot of fish? Because for an island nation, the Irish surprisingly eat very little fish and it’s not noted that the traditional Irish diet was big on fish. There’s fish and chips, which is from Britain and a recent dish. Before potatoes, the traditional Irish diet is said to have been very heavy on dairy, especially milk and butter and curds, though not much cheese, along with oats and other grains and pork and veggies like cabbage, onions and garlic.

  8. teageegeepea says:

    I had been under the impression that Iceland was peopled by Viking men and Irish women that they abducted, so their descendants would all be an even mix.

    • Frau Katze says:

      That’s what I thought too but it seems it was more complicated. I thought I read that mitochondrial DNA established that all the women were Irish. But maybe I’m out of date.

    • Halvorson says:

      The slaves were there to work on farms, not to be ogled at. About 75% of Icelandic Y-haplogroups and 37.5% of their mitochondrial DNA is of Scandinavian origin, a biased sex ratio very similar to the one seen in African Americans.

  9. Dividualist says:

    Don’t assume non-survival when non-reproduction or low-reproduction is sufficient. Thralls didn’t have to freeze or starve to death, it was enough if freeborn women were unlikely to marry them. Assuming they brought more male than female thralls. Even if they brought equal numbers, there are still reasons to assume low-status men would reproduce less than high-status men, the usual hypergamy thing. Female thralls would be both more willing and forced to be the concubines of their owners.

    Youl would have a similar situation in a Mediterrean paradise with 100 male rock stars, 100 female movie stars, 100 male plebs and 100 female plebs. Some male plebs don’t reproduce, some male rock stars have plebeian mistresses besides their movie star wife, and on the whole every generation is more and more having rock star genetics.

  10. Jacob says:

    “… which is behind a paywall.”

    Don’t pretend you don’t use SciHub. We’re all Russian hackers here.

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