Ancient DNA and Norden

By Razib Khan | August 2, 2010 3:29 am

Genetics is now being brought to bear on whether there were non-trivial population movements in the prehistorical period. Or more precisely, a combination of genetics and archaeology, whereby the archaeologists retrieve and extract genetic material which the geneticists amplify and analyze. This has helped establish that European hunter-gatherers were not lactase persistent. This is totally unsurprising, but was a nice proof of principle. When it comes to ascertaining genetic relationships among populations, as opposed to specific traits whose genetic architecture is well established, it’s a bit trickier. Who knows how many population movements may have interposed themselves between the present and a particular period in the past from which you have samples?

A new paper in PLoS ONE reports findings which do little to clarify, though add weight to skepticism as to the definitiveness of earlier results, Genetic Diversity among Ancient Nordic Populations:

Using established criteria for work with fossil DNA we have analysed mitochondrial DNA from 92 individuals from 18 locations in Denmark ranging in time from the Mesolithic to the Medieval Age. Unequivocal assignment of mtDNA haplotypes was possible for 56 of the ancient individuals; however, the success rate varied substantially between sites; the highest rates were obtained with untouched, freshly excavated material, whereas heavy handling, archeological preservation and storage for many years influenced the ability to obtain authentic endogenic DNA. While the nucleotide diversity at two locations was similar to that among extant Danes, the diversity at four sites was considerably higher. This supports previous observations for ancient Britons. The overall occurrence of haplogroups did not deviate from extant Scandinavians, however, haplogroup I was significantly more frequent among the ancient Danes (average 13%) than among extant Danes and Scandinavians (~2.5%) as well as among other ancient population samples reported. Haplogroup I could therefore have been an ancient Southern Scandinavian type “diluted” by later immigration events. Interestingly, the two Neolithic samples (4,200 YBP, Bell Beaker culture) that were typed were haplogroup U4 and U5a, respectively, and the single Bronze Age sample (3,300–3,500 YBP) was haplogroup U4. These two haplogroups have been associated with the Mesolithic populations of Central and Northern Europe. Therefore, at least for Southern Scandinavia, our findings do not support a possible replacement of a haplogroup U dominated hunter-gatherer population by a more haplogroup diverse Neolithic Culture.

Here’s a review of an earlier paper on this topic. Here’s an important section from the discussion of the current paper:

…Given our small sample sizes from these crucial time periods further studies are certainly required. However, the frequency of Hg U4 and U5 declines significantly among our more recent Iron Age and Viking Age Danish population samples to the level observed among the extant Danish population. Our study therefore would point to the Early Iron Age and not the Neolithic Funnel Beaker Culture as suggested by Malmström et al. (2009)…as the time period when the mtDNA haplogroup frequency pattern, which is characteristic to the presently living population of Southern Scandinavia, emerged and remained by and large unaltered by the subsequent effects of genetic drift. In contrast to Hg U4, which is only found in the Neolithic and Early Bronze Age samples, Hg U5 was observed in ~9% (5/53) of the remaining ancient samples and identified at all sites except Kongemarken and Skovgaarde.

I wouldn’t put too much stock in these specific results. The sample sizes and representativeness issues are probably such that each new paper is going to change our assessment. But, I think the section which I emphasized points to a shift in the Zeitgeist. Until recently there’s been a very strong bias among historical geneticists to assume that the genetic variation is more strongly affected by deep time events, and that recent replacements and perturbations will have less impact. I think there were good reasons for this assumption, and still are, generalizing from broader patterns. But the over-extrapolation of the rule-of-thumb may have led to models which will soon be falsified in many specific instances.

On a slightly bittersweet note, ancient DNA will be able to answer questions about the origins of many circumpolar populations, but will have far less to tell us about societies and cultures further south, simply because of less favorable conditions for preservation. The main exception to this truism will presumably be desert societies. For example, Tutankhamun has been typed as of the R1b Y lineage.

CATEGORIZED UNDER: Genetics
  • http://haquelebac.wordpress.com/2010/04/06/my-fossil-railroad/ John Emerson

    Whether there were non-trivial population movements in the prehistorical period….

    As far as prehistory goes, the default answer should be yes. (The Völkerwanderung was only prehistoric on the “barbarian” side, though the records in Latin and Greek history are garbled.)

    I will just repeat a few things I say from time to time here. One is that vast distances are not the problem. The distance between Beijing and Paris is about 5,000 miles, so someone could easily walk there and back in 10 years (10 miles a day, 100 days a year). Geographical impediments like mountains, deserts, swamps, thick forests, and raging rivers can be a serious impediment, but while immediately intimidating, they’re all either technically manageable or bypassable.

    I don’t think that motivation is a problem either. People talk about overpopulation and resource exhaustion, but I don’t think it has to be even as strong as that. There’s no particular reason to assume that all people in every society had a bias toward staying at home. Travel can be motivated by lots of reasons — religious quest, desire for new products, escape from enemies or the law, and finally land hunger. “Overpopulation” is a strength rather than a problem unless there’s a shortage of land, and even prosperous members of a prosperous society might migrate just to become even more prosperous, to become more independent, or to escape from enemies).

    As far as I can tell, the big impediments to long distance travel have been first, opposition by unfriendly peoples occupying the land, and second, provisioning, with the former the more important. Between the time Europeans knew about the existence of China to the time when they actually went there was about 2000 years, and the reason was that the intervening area was well-populated (by Turks, Persians, Sogdians, etc.), well-armed, and unfriendly to European travelers (for a long period this was in order to preserve a Persian trade monopoly. )

    On the other hand, provisioning long-distance travel in an unpopulated area can be difficult, so some degree of settlement by trade-friendly peoples like the peoples of Samarkand, Bulgar, Timbuktu, is very helpful (to say nothing of the imperial Mongols).

    Besides the modern Western migrations, even in historical times the Inuit, the Polynesians, the Turks, and the Bantus have moved into areas far distant from their original homes. The Polynesians were moving into empty territory, and the others had some sort of economic / military superiority to the peoples already there.

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  • Sandgroper

    Martin Rundkvist has pointed out to me that there was a lot of slavery in Iron Age Scandinavia. They were big time long distance slave traders. He says all modern Scandies must have slave ancestry dating from this period.

  • http://haquelebac.wordpress.com/2010/04/06/my-fossil-railroad/ John Emerson

    They sold slaves long distance, but didn’t buy them. They captured slaves in Ireland and N. Britain, and probably in slavic areas too.

  • Sandgroper

    John, you’re saying that a lot of slaves were not imported into Scandinavia?

    That’s the direct opposite of what Martin was telling me.

    I have no idea which is right.

  • onur

    Besides the modern Western migrations, even in historical times the Inuit, the Polynesians, the Turks, and the Bantus have moved into areas far distant from their original homes.

    Other known long-distance historical migrations (from the most recent to the least recent): the Mongols, the Arabs, the Slavs, the Germanics, the Romans, the Greeks and the Celts. Of course, we can also add to this list the largely historical migrations of the Han Chinese.

    As you already mentioned, the Polynesian migrations were mostly to empty territories. The Bantus and the Inuit had technological (including subsistence) superiority to the pre-existent populations of the migrated territories.

    This leaves us with the migrations of the Turkics, the Mongols, the Arabs, the Slavs, the Germanics, the Romans, the Greeks and the Celts. None of these peoples had any clear technological superiority to the pre-existent populations (except to some degree the Romans to most peoples of Western Europe), so their genetic impact is probably less (in most cases probably much less) than that of the migrations of the Bantus and the Inuit as well as of the modern (last 500 years) migrations of the Europeans to the technologically much inferior New World (the Mongols didn’t even spread their language and culture to the pre-existent populations in any significant extent and were mostly assimilated by them at the end). The genetic impact of the Han Chinese on the pre-existent populations is maybe the most complicated one as different regions of China probably had very different patterns of sinicization.

  • bioIgnoramus

    “all modern Scandies must have slave ancestry dating from this period”: and indeed virtually all modern humans must have slave ancestry dating from some period, though the first few times I said as much on American blogs I had abuse hurled at me. This I attribute to a disinclination to conceive of slavery that wasn’t white men owning negroes.

  • http://haquelebac.wordpress.com/2010/04/06/my-fossil-railroad/ John Emerson

    Sandgroper: I’m just saying that while slaves were imported into Scandinavia from Northern Europe, on the long distance route to Constantinople or Bulgar the trade was one-way.

  • Sandgroper

    bio – Greek democracy was built on slavery.

    So, fuck ‘em. American cultural hegemony is self-destructing as we speak.

  • Sandgroper

    John, thanks.

  • onur

    I’m just saying that while slaves were imported into Scandinavia from Northern Europe, on the long distance route to Constantinople or Bulgar the trade was one-way.

    Of course. South Europe and West Asia were too civilized and far away from Scandinavia to supply any meaningful number of slaves to the Scandinavians.

  • http://haquelebac.wordpress.com/2010/04/06/my-fossil-railroad/ John Emerson

    Mostly just too far away. And there wouldn’t be much point in selling a load of slaves in Bulgar and shipping back a load of different slaves to Sweden.

  • onur

    And there wouldn’t be much point in selling a load of slaves in Bulgar and shipping back a load of different slaves to Sweden.

    Well, jokingly speaking, that doesn’t sound so illogical, after all, that is how modern shipping business works (I know it because my brother works at an important position in a large-scale shipping – export/import – company). Seriously speaking, you are probably right.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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