The West Asian mix

By Razib Khan | September 10, 2012 8:42 am

IE-speaking West Europeans are West Asian-admixed relative to Non-IE speaking Basques. Dienekes explicitly confirms what seems obvious using ADMIXTURE. When I get a chance I’m going to see if this difference is evident when comparing some South Indian (non-Brahmin samples) I have against Gujaratis. For what it’s worth I am told that ADMIXTOOLS will be out this week.

CATEGORIZED UNDER: Genetics
MORE ABOUT: Indo-Europeans
  • toto

    Still not sure how you would ascribe this component specifically to IE, as opposed to some other SW Asian wave – such as first farmers. If Basques and Finns avoided genetic influence from IE, why not from others?

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    Still not sure how you would ascribe this component specifically to IE, as opposed to some other SW Asian wave – such as first farmers.

    what i think one needs to do is run contrasts of pairwise populations which are very genetically similar, but IE vs. non-IE. so you want to find aspects of the IE tips of the pairs which are shared with other IE tips. ergo

    swede:finn
    catalan:basque
    marathi:kannada
    kurd:assyrian

    all the pairs are genetically close. but if you can find a common signal across the IE, not shared with any of the non-IE, that’s informative. it could be something preceding IE, so it’s a plausibility argument.

  • Onur

    kurd:assyrian

    I would use Armenians instead of Kurds, since Armenians are genetically closer to Assyrians than Kurds are.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    #3, true. i would probably do both, but if only one, armenians would be preferable.

  • Karl Zimmerman

    I noticed in the Dodecad google doc the Brahui have only 0.5% “Caucasus,” while the Baloch have 5.5%. Those seem like two good populations to compare as well.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    #5, good point.

  • Nathan

    @Karl
    Previous blog posts show the Brahui very similar to the Baloch, except Razib once remarked that the Brahui appear less cosmopolitan than the Baloch, iirc less Indian.
    Over at Brown Pundits, it was remarked by a poster familiar with the area that only a small number of Brahui tribes are the original Brahui while the rest were assimilated Baloch. This could explain the close similarity between the 2 communities.

    That difference in the Caucasus component; could it be due to the Baloch originating in Aleppo while Brahui origins are somewhat contentious , being either remnants of pre Aryan peoples of the area or later migrants (appears to be the preferred hypothesis) from what is now India ?

    I wonder if the 1st paragraph is old info that has been superceded by new theories?

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    #7, indian emailers regularly argue that the brahui are migrants from central india based on philology. the HGDP brahui samples strongly argue against this by genetics; they’re barely ‘indian’ at all, in fact compared to even the pathans (they are off the ani-asi cline). you can save the argument genetically by appeal to unrepresentativeness of course.

  • Karl Zimmerman

    If I could ask a general question for a second. Out of all the components that Dienekes regularly finds, Gederosia confuses me the most. Most of his other major elements are either easily linked to major population groups, or else (like NW African, and I think SW Asian) are probably stabilized admixtures which come out looking like a major population movement.

    I can’t say the same for Gederosia. I can’t think of any population movement which would have swept out of the Balochi region, leaving genetic imprints throughout South Asia, Iran & the Caucasus, and oddly enough even Western Europe, where it peaks in Celtic populations, then Germans, Basque, most Latins, and finally very low rates in Eastern Europe (Slavs, Greeks, Finns, Hungarians, and Romanians). It’s probably pre-IE, because the Basque have it (although the Sardinans don’t), but it doesn’t show any correlation with Atlantic_Med or North_European, which you’d expect if it was a hybrid of first-wave farmers and/or Mesolithic Europeans and some other element.

    So color me curious.

  • ackbark

    9. Rather than farmers per se is it a flow of agricultural workers?

  • Grey

    @9
    “Out of all the components that Dienekes regularly finds, Gederosia confuses me the most.”

    Same.

    The general model i have in my head is of population density as a kind of pump which pushes people out in all directions (modified by path of least resistance) with a force proportional to the potential difference between the population densities in adjacent regions with equilibrium lines where multiple pumps cancelled out – so almost like a map of electrical or magnetic potential difference.

    The gedrosia element makes me wonder if at some point pre-farming there was a major forager pump somewhere in the world i.e. a place where the local foragers had a high population density relative to adjacent regions, so the foragers in that region spread out like a more diffuse and slower acting version of the farming pump.

  • pconroy

    @9 Karl, @11 Grey,

    I’ve speculated previously that R1 (and maybe R1b) were present in the Mehrgarh Culture, which may be the people who first domesticated Bos Indicus – Zebu Cattle – and spread Pastoralism from there. R2 was present nearby, and R1b is West and R1a is West and North.

    http://en.wikipedia.org/wiki/Mehrgarh

    I’ve also speculated that their accompanying mtDNA was T1a1 and especially T1a1a (which is 70% of T1a1).

    If I’m correct they spread initially Westwards towards Northern Iran, then across into the Northern Fertile Crescent. Their R1b descendants are the Assyrians, Armenians and Alawites of Syria.

    We know that Bos Taurus – European Cattle – was domesticated in the Middle East, and as I’ve speculated previously, maybe even in the shadow of the Taurus Mountains. It’s unclear whether Bos Taurus or Bos Indicus were domesticated first, but I’m going to guess it was Bos Indicus. These cattle from Mehrgarh were cross-bred with Bos Taurus from the Middle East highlands, to create a more lowland compatible cattle.

    Today we find cattle which are primary Bos Taurus + minor Bos Indicus North of the Caucasus, and in Medieval times the Ostrogoths brought their cattle with then from this area to NE Italy and cattle in this region that trace their ancestry to the Ostrogoths have minor Bos Indicus ancestry.

    When I recently tested with DNA Tribes, they have an interesting feature that shows which worldwide populations you are nearest to. My parents (100% Irish) are nearest Europeans, then Cypriots – before any Caucasus people – then Caucasus North and South, then Balochis, Pathans, Sindhis, and then other Middle Easterners, and some other North Indians before Arabs (Lambadi IIRC)

    So as I’ve speculated previously, the R1b/T1a1 pastoralists then went from Northern Mesopotamia/Southern Anatolia/Syria by boat to Cyprus, then from there throughout the Mediterranean islands or North African coast, and on to Morocco, where they turned North through Iberia and on to the Isles.

    This would explain why the Isles have higher Gedrosia/Balochi then Central/Eastern Europe.

    Alternatively, the route could have actually been via the Caucasus and onwards through Central Europe to the Isles – if and only if we allow for the Plague of Justinian actually causing truly horrific devastation in the 5th century, in Eastern and South Eastern Europe, which allowed for population replacement in these parts, via the Slav expansion from the forest/steppe region.

    I note that both parents, also have minor Lithuanian admixture, which may be a relic of this latter route, or may be due to Viking admixture later on.

  • https://plus.google.com/109962494182694679780/posts Razib Khan

    hey all, sometimes ‘clusters’ are actually just modal hybridizations. this could be the algorithm ‘finding’ a solution ;-) lead the algorithm by its nose, not the other way around!

  • Grey

    @12
    Yes i see what you mean. I was thinking earlier, pre-farming, and wondering what environments would have had the highest forager population densities and if the Gedrosia component might somehow be related to that.

    (I was thinking forager pumps might be deltas / wetlands / floodplains hence why the Indus delta would be a contender but it’s just a thought.)

  • pconroy

    @13 Razib,

    Well that idea would yield a 3rd possible solution to the “Gedrosia problem”.

    Dienekes used my idea of decomposing his Dodecad components, based on other components and yielded the following:

    Image:
    http://4.bp.blogspot.com/-G5HKtB9fZJs/UDcviIMZrLI/AAAAAAAAFvQ/cLoB5_uvXYQ/s1600/barplot.png

    Table:
    https://docs.google.com/spreadsheet/ccc?key=0ArJDEoCgzRKedC1ZRm1YcGJyMUV2cFNiTjRwTTk0THc#gid=0

    Caucasus is roughly:
    Gedrosia – 37%
    Atlantic-Med – 56%

    Northern Europe is roughly:
    Gedrosia – 33%
    Atlantic-Med – 65%

    So both the Caucasus and Northern Europe components have roughly the same proportions of Gedrosia and Atlantic-Med, where

    Atlantic-Med = Sardinian/Basque
    Gedrosia = Balochi

    So Atlantic-Med is mostly early Neolithic mainly agricultural wave, where Gedrosia might be a later Neolithic mainly pastoralist wave.

    I’m beginning to think that the original Northern Europeans were a fully Siberian like population, that have experienced something like 80-90% admixture from Atlantic-Med and Gedrosia type peoples.

    It may be that this ancient Siberian-like population were the Cro-Magnons, who were widespread in Northern Asia…

    The Irish have the widest malars in Europe (mid-face width), they are second only to East Asians in this feature…

  • Eurologist

    Not all admixtures into various populations need to have occurred during the same time frame. People from which the Balochi seem to mostly originate might at one point have lived in a much larger area (e.g., including much of Pakistan and Afghanistan) – the Gedrosia component is surprisingly large in the North:
    Tajiks (34%)
    Kumyks (20%)
    Uzbeks (18%)
    Selkup (7%)
    Ket (6%)

    Later, they became marginalized to mostly Balochistan. And, as I argued in Dienekes’ thread following Pconroy’s suggestion, those results indicate to me that Gedrosia indeed was isolated for a long time period.

    As I have argued before, the signature in Europe might go all the way back to paleolithic times (when we expect much of the initial settlement to have originated from/through ~Pakistan, based on putative haplogroup split locations).

    What Dienekes’ supervised runs show is that the sorting that defines Atlantic_Med was very good at removing Gedrosia, but the one that defines North_European was not. Thus, the fact that Atlantic populations have higher Gedrosia might in part be because the algorithm was better at sorting it out (perhaps indicating some more recent inflow).

    Following this line of thinking, the algorithm was also very good at defining Atlantic_Med separating out North_European – but not vice versa. This again might indicate recent flow from the North to the SW (that was easy to separate), but a more ancient origin of North_European connected to Atlantic_Med that was more difficult to separate.

  • pconroy

    @16 Eurologist,

    Oh I agree that the Gedrosia component once probably covered a much larger area.

    When I look at fastIBD, I see that my parents have IBD segments with:
    Abhkazians, Brahui, Chechens, Chuvash, Dhakars, Dolgans, Gujarati, Iranian, Kalash, Kanjars, Kazakh, Kshatriya, Kumyks, Lezgin, Makrani, Mordvinian, Nganassan, Nogays, North_Ossetian, Pathan, Piramalai, Selkups, Sindhi, Tadjik, Tharus, Tu, Turkish, Turkmen, Ukrainian, Uzbek_Jewish, Vologda_Russian

    So many Central/South Asians… some of these no doubt linked to the Gedrosia component – though some also to Siberian

    Oh and they also have East_Greenland and West_Greenland

  • pconroy

    @16 Eurologist, #2

    Oh I agree that the Gedrosia component once probably covered a much larger area – Full list.

    When I look at fastIBD, I see that my parents have IBD segments with:
    Abhkazians, Adygei, Altaian, Balkar, Belorussian, Bengali1, Brahmins_UP, Burusho, Brahui, Chechens, Chuvash, Dhakars, Dolgans, Dusadh, Evenk, Gujarati, Hazara, Iranian, Kalash, Kanjars, Kazakh, Kshatriya, Kumyks, Kurdish, Lezgin, Makrani, Mordvinian, Nganassan, Nogays, North_Ossetian, Pathan, Piramalai, Selkups, Sindhi, Tadjik, Tharus, Tu, Turkish, Turkmen, Ukrainian, Uzbek_Jewish, Vologda_Russian, Xibo, Yakut

    So many Central/South Asians… some of these no doubt linked to the Gedrosia component – though some also to Siberian

    Oh and they also have East_Greenland and West_Greenland

  • Onur

    Oh I agree that the Gedrosia component once probably covered a much larger area – Full list.

    When I look at fastIBD, I see that my parents have IBD segments with:

    Abhkazians, Adygei, Altaian, Balkar, Belorussian, Bengali1, Brahmins_UP, Burusho, Brahui, Chechens, Chuvash, Dhakars, Dolgans, Dusadh, Evenk, Gujarati, Hazara, Iranian, Kalash, Kanjars, Kazakh, Kshatriya, Kumyks, Kurdish, Lezgin, Makrani, Mordvinian, Nganassan, Nogays, North_Ossetian, Pathan, Piramalai, Selkups, Sindhi, Tadjik, Tharus, Tu, Turkish, Turkmen, Ukrainian, Uzbek_Jewish, Vologda_Russian, Xibo, Yakut

    So many Central/South Asians… some of these no doubt linked to the Gedrosia component – though some also to Siberian

    Many of these populations are not Central or South Asian. There are eastern European, West Asian, Caucasian, Siberian and even East Asian populations among them, and many of them have little or no “Gedrosia” and/or “Siberian” components. So I did not understand your logic behind listing these populations.

  • pconroy

    @19 Onur,

    Gedrosia decomposes to Caucasus + Siberian – so has a stabilized minor Siberian component.

    My parents are Irish, so how would they have IBD (or in some cases IBS) segments with such a variety of peoples if the Gedrosia component was not once a factor in a lot of Central Asia and NW India and even Eastern Europe.

  • Onur

    Conroy,

    As I said, many of the populations you listed have little or no “Gedrosia” and/or “Siberian” components. So your and your parents’ IBD sharing with many of those populations probably has nothing or very little to do with the “Gedrosia” and “Siberian” components. You can actually check whether your and your parents’ IBD sharing with those populations are in the parts of genomes that carry the “Gedrosia” or “Siberian” components and how often for each population. I would do such a check if I were you.

    If I were you, I would list all the populations worldwide from the one with the most IBD sharing with you and/or your parents’ to the one least to be so, providing numbers of the amounts of IBD sharing. Also, you should compare your and your parents’ genetic results with those of other Irish and people from neighboring ethnic groups more often and evaluate your and your parents’ genetic results accordingly. Without such comparisons, your and your parents’ genetic results cannot tell much about your family’s genetics.

  • pconroy

    @21 Onur,

    Well I have a 93 Mb file – courtesy of the Eurogenes Project – that contains IBD information of about 3,000 people with 1,700,710 IBD pairs listed.

    I’ve extracted my parents info, and am in the process of extracting other Irish people’s info. So far my parents are fairly typical of Irish people.

    The difference though is that on average they have more Nordic ancestry – especially my Mother – than other Irish. Also, some other “Irish” are not really Irish, in that they have parents or grandparents from populations like Czech Republic and French Canadian – 2 that I know of.

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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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