Sunday, April 19, 2015

How Little We Know About Ancient DNA

I've frequented several of the Ancient DNA discussion boards lately, and have been flummoxed by the self-important, self-promoted, self-described "experts," who proclaim to know precise migration patterns of Ancient Europeans.

These same "experts" even go so far as to claim to be able to tie specific haplogroups to languages, tribes, and epochs.  They will make broad statements, like, "all of Europe was populated by [this haplogroup or that], which represented the [Cro-Magnons or whatever], until they were replaced, en masse, by the [new Haplogroup.]"

(Often the dominant invader haplogroup in their theories tends to be the one of the posting "expert," but that's just coincidence, I'm sure.)

Contrasting these experts are some bona fide theoreticians, who point out that we have less than 100 samples of Caucasian Ancient DNA, and that a simple cultural fact, for example, if one tribe cremated their dead and another tribe buried their dead, could contribute to the number of ancient skeletons that make it to the present day.

So, what I decided to do was to plot the confirmed ancient NR Y Chromosome haplogroup samples on a map, to show whatever it shows.

What I discovered was a complete lack of any real patterns.  In other words, it's too early to tell.  We need way more aDNA.

I used the excellent data from Ancestral Journeys.  All maps are labeled.  All times and locations are approximate.  All maps are copyrighted, but feel free to share, as long as you link to this page or attribute to me.  (The final map is not mine, but purports to represent modern majorities).







I think from these maps it is clear that several of the widely accepted theories are bunk.  For example, looking at these maps, it is clear that Haplogroup G2 is a candidate too for one of the original populations of Europe.  It was ubiquitous.  The wiseguys all postulate that it originated in the western Caucasus, near where it is currently dominant, and moved west with the migratory herders or agriculturalists.  However, it is just as likely from looking at these maps that it once simply was everywhere, in a band in central Europe, along the major rivers, stretching from northern Spain to the Caucasus, and that its current location is one where it RECEDED to, not originated from.

What other theories can be questioned by these maps?


3 comments:

  1. Great maps, thank you. You are missing the R1a1* in Karelia (at the site of Yuzhniy Oleniy Ostrov on Lake Onega) c. 5500 BC, though.

    The reason that Y haplogroup G2a is proposed to have come in with the Neolithic is not really because of its distribution, but because the people carrying it (and buried in Neolithic sites) had autosomal DNA very distinct from that of those identified as foragers. People with the forager type (WHG) autosomal ancestry have been found adjacent to people with Neolithic type (EEF) ancestry in several parts of Europe (Hungary, northern Spain, and southern Scandinavia). Such a situation could not plausibly arise without recent migration, and of course distinct material cultures and means of subsistence did in fact spread at the right time and in the right places. Since the Neolithic autosomal type is closest to modern Near Eastern (and generally circum-Mediterranean) people, while the WHG type is closest to modern northern and western Europeans, it is natural to conclude that the Neolithic type immigrated from the Near East (or perhaps originated in the Balkans).

    G2a is absent from our (miniscule) sample of foragers and predominant in our (somewhat less inadequate) sample of Neolithic farmers; G is most diverse in West Asia (and hence most likely to have originated there); and there is no reason to suppose that the immigrant farmers would have lost the Y chromosomes they brought in and replaced them with native ones while gaining only a modest amount of forager ancestry.

    That is not to rule out the possibility that G2a and/or EEF could have existed in southern Europe prior to the Neolithic (we have no aDNA), or that some clades of G2a found in the Neolithic farmers could have been acquired from foragers in Central Europe. I don't think the latter is very likely, but the former is quite plausible.

    So, while I whole-heartedly agree that a lot of people jumping to amenable conclusions with far too little data, the Neolithic-G2a connection is a lot better founded than you are making out.

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  2. You forgot about Karelian R1a1 from ca. 5500 - 5000 BC, but other than that - good map.

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  3. That Karelian man was buried on Red Deer Island, Lake Onega:

    Check its location: http://www.umich.edu/~anth282/Olenii.pdf

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