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Thursday, November 26, 2015

The Khvalynsk men

This is where the three Samara Eneolithic or Khvalynsk samples from the recent Mathieson et al. paper plot on my Principal Component Analysis (PCA) of ancient West Eurasia. They're labeled as Steppe_CA (steppe Copper Age). I've also marked them with their Y-chromosome haplogroups.

Individual 10433, belonging to Y-chromosome haplogroup R1a, is almost a pure Eastern European Hunter-Gatherer, which is perhaps surprising, considering he was buried with copper artifacts. On the other hand, sample 10434, the one belonging to haplogroup Q1a, and positioned further east than the other two, appears to have been whacked over the head a few times and simply thrown into a ditch.

The PCA also has most of the other samples featured in Mathieson et al., including Neolithic Anatolians (labeled Anatolia_N), as well as extra samples from Allentoft et al. and Jones et al.

See also...

The Khvalynsk men #2

Monday, November 16, 2015

CHG and the Indo-European question

The recent Jones et al. palaeogenomics paper focusing on Caucasus hunter-gatherers (CHG) has this to say about the Indo-European and Indo-Aryan expansions:

CHG left their imprint on modern populations from the Caucasus and also central and south Asia possibly marking the arrival of Indo-Aryan languages.


It has been proposed that modern Indians are a mixture of two ancestral components, an Ancestral North Indian component related to modern West Eurasians and an Ancestral South Indian component related more distantly to the Onge [25]; here Kotias proves the majority best surrogate for the former [28,29] (Supplementary Table 10). It is estimated that this admixture in the ancestors of Indian populations occurred relatively recently, 1,900–4,200 years BP, and is possibly linked with migrations introducing Indo-European languages and Vedic religion to the region (28).


Finally, we found that CHG ancestry was also carried east to become a major contributor to the Ancestral North Indian component found in the Indian subcontinent. Exactly when the eastwards movement occurred is unknown, but it likely included migration around the same time as their contribution to the western European gene pool and may be linked with the spread of Indo-European languages. However, earlier movements associated with other developments such as that of cereal farming and herding are also plausible.

To their credit, in that last quote the authors leave open the possibility that CHG arrived in South Asia in multiple waves and with a variety of groups, including Neolithic farmers. Nevertheless, I'd say their comments are still confusing and perhaps also incredibly naive, because essentially they appear to be hoping that in CHG they've identified the Proto-Indo-European and Proto-Indo-Aryan genetic component.

Indeed, a lot of people actually believe that the overwhelming part of the West Eurasian admixture in South Asia should be attributed to the Indo-Aryans. But that's just stupid.

After all, many Dravidian groups that in all likelihood never spoke Indo-Aryan languages carry significant ratios of West Eurasian ancestry. Some of this influence can be explained by admixture with Indo-Aryans, but uniparental markers suggest that much of it was brought from West Asia by the Proto-Dravidians (see here).

Below is the aforementioned Supplementary Table 10. Note that two of the Indian populations that are best modeled with D-stats as mixtures of Kotias (one of the two CHG genomes) and Onge are Dravidian speakers (Mala and Vishwabrahmin or Viskwakarma, a Malayali community). Another three are Indo-Aryans (GujaratiC, GujaratiD and Lodhi), but with high levels of Ancestral South Indian (ASI) admixture, which suggests their ancestors might have been language shifters.

On the other hand, the three populations that are best modeled as Afanasievo (a pastoralist group from the Early Bronze Age steppe) and Onge are all Indo-Aryans (GujaratiA, GujaratiB and Tiwari).

But like I say, South Asia is a complex melting pot of Indo-Aryans, Dravidians, and several other linguistic groups, so a more comprehensive analysis than a comparison of a few D-stats is needed to unravel the origins of its people in a meaningful way.

By the way, Jones et al. also argue that CHG is basically an offshoot of the so called Basal Eurasian clade, which was first described in Lazaridis et al. 2014. I'm highly skeptical of this claim, and I might check it out after I get my hands on the CHG genomes.


Jones, E. R. et al. Upper palaeolithic genomes reveal deep roots of modern eurasians. Nat. Commun. 6:8912 doi: 10.1038/ncomms9912 (2015).

See also...

The "fourth strand" of European ancestry came from the Caucasus

The "fourth strand" of European ancestry came from the Caucasus

From a news feature about a forthcoming palaeogenomics paper:

"The question of where the Yamnaya come from has been something of a mystery up to now," said one of the lead senior authors Dr Andrea Manica, from Cambridge's Department of Zoology.

"We can now answer that as we've found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation. This Caucasus pocket is the fourth major strand of ancient European ancestry, one that we were unaware of until now," he said

Read more at: 'Fourth strand' of European ancestry originated with hunter-gatherers isolated by Ice Age

Update: the paper is now out and open access at Nature Communications.

The two ancient Georgian genomes belong to Y-chromosome haplogroup J. So it looks like I was right when I said that this type of ancestry mostly entered the European steppe from the Caucasus via female mediated gene flow during the Bronze Age (see here and here).

However, one of the Eastern European Hunter-Gatherers (EHG) from Mathieson et al. 2015 also belonged to haplogroup J. This suggests that there was intermittent gene flow, including some paternal gene flow, between the Caucasus and the steppe well before the Bronze Age.

Nevertheless, it's now even more difficult to accept that Y-haplogroup R1 and the Proto-Indo-Europeans might have originated south of the steppe. Clearly, R1 appears to be a steppe marker from way back, and I seriously doubt that Indo-European languages were introduced into highly patriarchal steppe societies by female migrants from the Caucasus.

Image credit: Nature Communications,