The layers and fault-lines of genes

By Razib Khan | November 11, 2010 4:04 pm

800px-Cross-cutting_relatio

At Genomes Unzipped Luke Jostins elaborates on how the genetic facts he now has about his paternal lineage change how he views his own personal history:

… my father’s father is Latvian, and the N1 haplogroup is not rare in the Baltic regions. In fact, the subgroup, N1c1, is more common in parts of Eastern Europe than it is in Asia.

Initially, this seemed to play nicely into a part of our ancient family history. There is a folk history, relayed to me be my Dad and my uncle Johnny, that Jostins blood may contain traces of Mongolian. The justification for this is that in around 1260, just before the civil war caused the Mongol Empire to die back in Europe, the Empire extended all the way to the Baltic States. It was at this point, my fellow N1c1-bearers hypothesise, that Mongolian DNA entered the Jostins line.

Unfortunately on closer inspection this tale is not really supported by the DNA evidence. The famous Mongol Expansion haplogroup is actually C3, which is the modal haplogroup of Mongolians. In contrast, N1c1 has existed in Europe for thousands of years, and is far to old and too wide-spread to represent a recent expansion.

dnanlargergTo the left is a frequency map of the concentration of N1c1. Based on the current distribution, and the diversity being modal in the East Baltic, one has to be skeptical of a simple east-west model. Interestingly the frequency difference of this haplogroup between Finland and Sweden is very high. Also, branch of N1c1 seems to be found among the Rurikids of Russia. This was the ruling dynasty of the Rus, a people who originally seem to have been ethnic Scandinavians from Sweden. Eventually they ruled over a polyglot state of Finns, Slavs and Scandinavians, and submerged their own identity with that of the Slavic peasants. In this they followed the example of the Bulgars, who were ethnically distinctive from their Slavic subjects, but were totally absorbed excepting that their ethnonym persisted. There is some evidence that the Serbs are a similar case, an Iranian group which was eventually absorbed into the South Slav substrate.

Going back to northern Europe, let’s try to get some more perspective. Luke Jostins’ personal history is after all a slice of population history, and what we know about the background of the population impacts how Luke views his own personal history. To do that I thought I’d quickly poke around a few older papers on Baltic genetics which I had stashed away. It didn’t turn out to be so quick. But here are some figures. First, from Genome-Wide Analysis of Single Nucleotide Polymorphisms Uncovers Population Structure in Northern Europe:

finplos

From Genetic Structure of Europeans: A View from the North–East:

fi

Finally, from Migration Waves to the Baltic Sea Region (N3 = N1c1):

finfinal

Also see my recent posts on Northern European genetics, as well as the argument about agriculturalists vs. farmers. Ten years ago we have a few simple models, but now it gets more confusing and complicated. Confounders:

- Different reproductive skew parameters for males and females. In short, high fertility of “super-males” as well as dominance of patrilocality can produce different patterns in Y and mtDNA

- Selection on mtDNA. The “neutral” markers which we think of as neutral may not be neutral

- Poor correspondence between inferences of the past based on contemporary patterns of variation and what ancient DNA has discovered. Our assumptions are faulty, or we’re just too stupid to extract the real patterns

- Persistent problems with dating and typing some uniparental lineages. Consider the debate over the pan-Eurasian haplogroup R1a1a* (Dan MacArthur and I both carry this Y lineage, but what’s in a few letters?)

- Reality is complicated. This may be the most intractable issue over the long term

I have used the analogy of a palimpsest to describe the flow of genetic variation over time and space. I think that perhaps that that is misleading in some fundamental ways. Demographic patterns are characterized by different dynamics, persistent and long standing “flows,” as well as punctuated “explosions.” Rather than a palimpsest, a better analogy might be the layering of geological strata. Although there are long periods of gentle wearing and layering, volcanism and earthquakes periodically erupt to disrupt the smooth accumulations. Sequences of catastrophic events can produce inversions.

Consider three dynamics:

- Isolation-by-distance. This is the conventional band/village-to-band/village process of gene flow. This may be analogized to sedimentary accumulation (mutations) and erosion (drift)

- Demic diffusion. The rapid demographic expansion into virgin territory by a culture which introduces a more efficient mode of production. One of the most recent occurrences of this was the rapid multiplication of New England Puritans from ~30,000 circa 1640 to over 700,000 150 years later. Not only did these New Englanders “fill up” their home territory, in the early years of the republic they burst out of the northeast and populated many regions of the Great Lakes. Demic diffusion is like an earthquake, a rapid and ordered shift of the local geology

- The leap frog. The settlement of Europeans in the southern cone of Latin America, Australia, or Mongols in eastern Iran, are instances of leap frogs. We have clear textual of these leap frogs, but without that we wouldn’t know what to make of them. Leap frogs are like volcanic eruptions, reordering the layers beneath and also deposition from above

At least with Luke’s hypothesis about descent from Rurik he can test his own N1c1 profile against other Rurikids. Presumably the modal haplotype and its near relations are those of the original Rurik.

CATEGORIZED UNDER: Genetics, Genomics
  • The Dude

    What is the basis for stating that the dynasty of Rurik was haplogroup N?

    I assume this vignette was lifted from Wikipedia, and upon further perusal of the guilty link many LOLz were had:

    http://www.familytreedna.com/public/rurikid/default.aspx

  • bioIgnoramus

    ” the southern cone of Latin America”: ‘ACHU’, remember.

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  • onur

    From the Dude’s link:

    In opinion of administrators of this project a considerable number of males, especially in the former USSR and in Finland, are descended from Rurik.

    I think that is a plausible theory (in fact, I intuitive had already a similar theory in mind) given the fact that Lithuanians of the Behar et al. study have almost 0% Mongoloid component despite the fact that they have a high frequency of Y haplogroup N1c1.

    This Rurik guy may actually be a Finno-Ugrian or a Swedicized Finno-Ugrian.

  • onur

    Typo correction for “I intuitive had” in comment #4: I intuitively had

  • The Dude

    Onur, I agree that it is quite possible that Rurik was N; I’m just curious as to what the basis is for saying he was more likely to have been N than I.

    In fact, with what confidence can we speculate on the distribution of certain haplogroups a mellenium ago, given the large scale movements of people and the adoption/absorption of them and their cultures from effectively one end Eurasia to another?

    Could the current distributions have crystallized only after relatively recent and rapid population expansions?

  • onur

    I’m just curious as to what the basis is for saying he was more likely to have been N than I.

    Well, I don’t know the details of their theory, my comment was due to the fact that their theory sounds plausible based on the current haplogroup distributional and autosomal genetic pattern of the region. In fact, I’ve been thinking on a similar theory based on the genetic pattern of the exact same region for some time.

    In fact, with what confidence can we speculate on the distribution of certain haplogroups a mellenium ago, given the large scale movements of people and the adoption/absorption of them and their cultures from effectively one end Eurasia to another?

    I think for full verification we need ancient DNA studies.

    Could the current distributions have crystallized only after relatively recent and rapid population expansions?

    Y-chromosome is much more open to change and rapid expansions than mtDNA and autosomal DNA because of the ubiquitous patriarchal culture of humans, and there are historical examples like Genghis Khan (I don’t know how much verified the Genghis Khan theory is), so why not?

  • onur

    Well, I don’t know the details of their theory, my comment was due to the fact that their theory sounds plausible based on the current haplogroup distributional and autosomal genetic pattern of the region. In fact, I’ve been thinking on a similar theory based on the genetic pattern of the exact same region for some time.

    Also, until reading this thread I had no knowledge of Rurik or his line, so my own theory was completely based on the genetic pattern of the region, not any historical knowledge. For my own part, this adds weight to the Rurikid line theory and similar theories about the region.

  • http://www.genomesunzipped.org Luke

    @onur @Dude

    The haplogrouping of Rurik is based on the fact that a number of extant royal houses have pretty good claims of descent from Rurik; genotyping a number of individuals from these houses reveals that about 60% (from diverse regons) are N1c1, and in-fact share a number of unique mutations on top of the standard N1c1-defining sites.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    the same logic works with the descendants of ali and genghis khan (the princely lineages of eastern mongolia claim direct descent). if the other 40% are due to infidelity, that’s about a 1% rate per generation. though some of these people were probably frauds who managed to insert themselves into the broad rurikid family, so i assume that misattributed paternity rates might be even lower.

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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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