Razib Khan One-stop-shopping for all of my content

March 10, 2021

Indo-Europeans!

Filed under: Indo-Europeans — Razib Khan @ 1:38 pm


For some pieces on my Substack I’ve been re-reading a lot of the stuff on the ancient genetics and archaeology of Eurasia as they relate to Indo-Europeans. This means I get a different view from usual…as it’s more synoptic. I’m not entirely clear on the dates or archaeology, but here is what I’ve concluded: the Indo-European expansions can be partitioned into “waves.” That is, they weren’t a simple “demic diffusion” where disease (against their rivals) and reproductive excess generated a continuous expansion across their range.

So here’s what I get

1 – An “early phase” where Yamna people push west (Kurgan) and become Corded Ware, and east (far) and become Afanasievo. Date this to right before 3,000 BC, but pretty much “completes” in Europe by 2900-2800 BC, as the broad zone of Central and Northeast Europe is dominated by these people (there are still debates on whether Afanasievo became the “Tocharians”; I think they did)

2 – ~2500 BC, 400-500 years after the initial push west, Indo-European populations push beyond their limits on the Rhine, and breakthrough past the mountains ringing the Southern European peninsulas. The dates are often vague in the south, but it looks to be around 2500 to 2000 BC. For example, the Neolithic farmer descended Remedello Culture in northern Italy ends about 2400 BC. The Bell Beaker Indo-Europeans seem to have arrived in Ireland and England at just about this time, perhaps a century after they came to dominate France.

Though there were obviously islands of exception (often quite literally as in Sardinia and Crete), Europe by 2000 BC was Indo-European.

3 – The third wave dates to after 2000 BC, and it is the “Asia reflux.” Populations used the forest-steppe zone as a stepping stone out to the east. Derived from the same synthesis between Yamna and European farmer as Corded Ware, these populations seem ancestral to the Indo-Iranians. Slavic-speaking people (or the ancestors of those people) occupied the western fringe of this expansion zone, and by the Iron Age had begun to move east, marginalizing Indo-Iranians across much of their core European territory.

It seems that Indo-Iranians had pushed into the margins of northeast Iran, Khorasan, by ~2000 BC. In the period between 2000-1500 BC they clearly began to occupy their historical core zones in Iran and India. Obviously, Indo-European Iranians are present in western Iran by 1000 BC in the historical record, though Indo-European Mitanni are present by 1540 BC at the latest in Syria and northern Iraq.

The Iranians also moved into the Tarim basin, so the cities of the west and southern edge were Iranian-speaking (the cities of the north and east were Tocharian).

What explains these pulses? I don’t know totally, but we know a few things:

– There are star phylogenies on the Y chromosomal associated with these migrations. R1b, R1a, and I1. I think the last is due to the assimilation of non-Indo-European men in Europe, but the first two are clearly primal. The Indo-Europeans were clearly very patrilineal.

– The last, Asian, migration clearly has something to do with chariots and horses. The coincidence in timing seems too much. But the earlier migrations were before chariots (I believe). But, the horse does seem to have come with Indo-Europeans, so there was a level of mobility involved.

– The “Bell Beaker” motif seems to have emerged among non-Indo-Europeans in Iberia, and spread to Indo-Europeans, who expanded outward. I think we’re seeing something related to religion.

Unfortunately for I suspect that the Indo-European advantage was “social technology”, not material technology. Social technology is hard to infer in a preliterate society.

Question for readers: Can you nail down the chronology better? Those who know archaeology?

June 30, 2020

Chariots and Aryans

Filed under: Indo-Aryans,Indo-Europeans — Razib Khan @ 6:32 pm


Readers know I do not like to watch YouTubes, but Mukunda is a member in-good-standing of the community, and a great host of the Browncast, so I did watch it.

My general reaction is “OK.” I don’t see how it changes my own views much at all. We know that the arrival of Kurgan people into Europe between 3000 and 2500 BC was not accompanied by the “light chariot.” Rather, they arrived in wagons. As it happens, the steppe people replaced 50-75% of the ancestry in Northern Europe, and 25-50% in Southern Europe. Contrary to I’ve been led to believe from Hollywood films apparently the primary utility of the chariot is as a transport vehicle, especially on flat ground. The light war chariot is presumably a major improvement on the cart, but the difference was presumably quantitative not qualitative.

Mukunda says that another foundation has been ripped from the Aryan migration/invasion theory. I don’t see it that way at all, because I don’t really know that this theory has too many detailed foundations. Mukunda’s response is pretty common, and I think some of the discordances here is that Indians have been educated in a way where many specific elements of the theory are presented as definitively and finally true. On the whole of course, real science does not work that way.

Here is what I know as a geneticist and have seen in the data.

– Genetic ancestry related to Corded Ware/Sintashta people of Eastern Europe and Central Asia contributes about 10-30% of the ancestry in Pakistan and Northern India (depending on the population)

– Y chromosomal lineage R1a1a-Z93 is ~15-25% of the subcontinental haplogroups. This lineage was discovered first in the “forest-steppe” of Europe’s southeast fringe with Central Asia and the Caucasus

– There are very few (though there are some) mtDNA haplogroups in South Asia that are found in Sintashta-Andronovo graves

The Sintashta seem to date from 2400 to 1800 BC as a culture. Additionally, the evidence from Turan and Khorasan in the ancient DNA does not indicate much steppe ancestry before 2000 BC.

To be frank, without genetic data I would not find a population admixture of 10-30% from a steppe group into the northwest subcontinent plausible on the face of it. Perhaps 1-3%. But the data are what they are, and we need to accept them. It is also plausible to me that the initial waves of migration into South Asia were not quite as male-biased as we think, as the proto-Indo-Aryans may have mixed with eastern Iranian/Indus periphery populations before arriving into Punjab. This would mean the population displacement is actually higher in demographic terms. The figures above only give percentages of “steppe”, and assumes pure admixture, which seems unlikely to me.

One hypothesis is that the IVC people already spoke Indo-Aryan languages. Perhaps the newcomers from the steppe assimilated into the local substrate, taking positions at the top of the caste hierarchy? I am skeptical of this. The Indo-European languages don’t exhibit the right structure for this model, as the European ones don’t form a natural closely related clade against the Iranian-South Asian ones. Rather, Indo-Aryan and Iranian seem closer to the Slavic clade.

As for all the rest, the details are interesting to me, but I don’t rest my inference on that. To be frank, some of the claims remind me of arguments I had with Creationists twenty years ago. It seems that they thought I had a very specific idea of what evolution is in all its details, so refuting one element refuted the theory. But that wasn’t it at all. Evolution is a broader framework, and many of the details have to be worked out.

That’s my general attitude to the Indo-Aryan migration into the subcontinent. It’s probably the right model. And we’ve pegged some details down. But a lot remains mysterious. Could the “Out of India” theory be right? The probability is definitely higher for that than that evolution is wrong. But on the whole, I am skeptical.

April 19, 2020

The brotherhoods of the plains

Filed under: Indo-Europeans — Razib Khan @ 3:32 am

One of my favorite concepts is “evoked culture.” This is basically pointing to the fact that some human cultural forms and practices aren’t contingent and arbitrary, but naturally emerge due to the canalization imposed by our cognitive biases and the physical and social world around us. An example Spencer Wells likes to use to illustrate this is that indigenous hunters on the Andaman Islanders immediately took to dogs as helpmates when they were introduced to them. The coadaptation between domestic dogs and humans is clearly intense and natural.

Horses are another example. The Plains Indians of the New World became some of the most fearsome mounted warriors in history after the Spaniards introduced domestic horses. By the 18th century some tribes, such as the Comanche, were fully mounted and mobile. This occurred over 200 years.

As documented in 2010’s Empire of the Summer Moon the Comanche recaptiulated some of the patterns of steppe pastoralists of the past: they integrated women of other people into their nation while committing acts of brutal violence against those other people. The last great chief of the Comanche, Quanah Parker, was the son of a white Texan woman.

I think of the Comanche when I wonder what the early steppe peoples were like. The Scythians, Sarmatians, the Sintashtas and Turks. The impact of the horse on their lifestyles, and the centrality of the horse, still echoes down to the present. The Central Asian Turks still drink mare’s milk. Indian grooms still ride on a white mare at their wedding.

But one of the major themes in pastoralist communities seems to be patrilineality and integration of local women. This seems to be illustrated in a new paper, Corded Ware cultural complexity uncovered using genomic and isotopic analysis from south-eastern Poland:

During the Final Eneolithic the Corded Ware Complex (CWC) emerges, chiefly identified by its specific burial rites. This complex spanned most of central Europe and exhibits demographic and cultural associations to the Yamnaya culture. To study the genetic structure and kin relations in CWC communities, we sequenced the genomes of 19 individuals located in the heartland of the CWC complex region, south-eastern Poland. Whole genome sequence and strontium isotope data allowed us to investigate genetic ancestry, admixture, kinship and mobility. The analysis showed a unique pattern, not detected in other parts of Poland; maternally the individuals are linked to earlier Neolithic lineages, whereas on the paternal side a Steppe ancestry is clearly visible. We identified three cases of kinship. Of these two were between individuals buried in double graves. Interestingly, we identified kinship between a local and a non-local individual thus discovering a novel, previously unknown burial custom.

This seems a consistent pattern: “steppe” ancestry seems to be mediated through male migrations. There are likely differences between agro-pastoralists (like the early Germans who moved into the Roman Empire), and full-blown nomads like the Huns, Turks, and Mongols. But overall the trend seems to be the rise of a particular patriarchal culture with the horse people, along with the spread of gods of the sky and lacking attachment to a particular place.

March 4, 2020

The enormous demographic impact of the Indo-Europeans

Filed under: Corded Ware,Historical Population Genetics,Indo-Europeans — Razib Khan @ 2:01 am


When I was a kid I remember seeing a map of the distribution of Indo-European languages, and being perplexed by their spread and distribution, from the North Sea to the Bay of Bengal. Later, I learned and understood that language families can spread by diffusion and cultural assimilation. In The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World David Anthony outlines an elite emulation model of the Indo-Europeanization, whereby groups of warriors associated with the Kurgan cultures took over and reshaped a broad range of societies.

The samples Anthony provided were instrumental in recalibrating his own model. It turns out that steppe migrants were extremely genetically impactful. Rather than a small minority, many archaeological cultures seem to have been predominantly steppe in genetic origin (total number of ancestors). The best estimates seem to be that ancestry from the steppe is somewhat more than half the total in northern and eastern Europe, and somewhat less than half in southern and western Europe (i.e., northeast to southwest cline).

More recently, it also seems that a substantial, though a smaller, proportion of the ancestry in southern Asia also derives from the steppe peoples. Within India itself, the range seems to be from 25-30% among some groups, such as North Indian Brahmins and Jatts, to a more typical range between 5 and 15% (peasant castes in South India are closer to the former, peasant castes in the Gangetic plain are closer to the latter).

Using the proportions in various ethnic groups in the Indian subcontinent, as well as across European nations, I have come to conclude that around ~10% of the ancestry in the world derives from people who were members of the “Yamna Horizon” ~3000 BC.* I don’t know the archaeology well enough to be highly informed, but I’m willing to bet that closer to 1% of the world’s population lived in and around the Yamna Horizon, so over the last 5,000 years, you’ve seen a 10-fold increase in representation of this ancestral component. More concretely, I think that the vast majority of the increase occurred between 2500 BC (when expansions into Britain and Southern Europe seem to have occurred) and 1000 BC (when the core area of the Indian subcontinent was Aryanized).

* I did stuff like weighted caste groups in Uttar Pradesh, looked at the populations of India states, added Pakistan and Bangladesh, as well as assigning estimates to European countries. I did some back-of-the-envelope for North and South America (e.g., assume that 50% of the ancestry is Iberian, and assume that 25% of that 50% is steppe).

May 16, 2018

Migration at the roof of West Asia

Filed under: Historical Population Genetics,History,Indo-Europeans — Razib Khan @ 10:16 pm
Click to see the full figure

The figure to the left is from The genetic prehistory of the Greater Caucasus. If you are a regular reader of this weblog, or Eurogenes, you can figure out what’s going on, and keep track of the terminology. But in 2018 I think we’re getting to the end of the line in making sense of “admixture graphs” in relation to West Eurasian population structure. The models are just getting too complicated to keep everything straight, and the distinct-populations-subject-to-pulse-admixture seems to be an assumption that may not necessarily hold.

To get a sense of what I’m talking about, the above preprint focuses on populations in and around the Caucasus region. One of the major reasons that this is important is that the Caucasus was and is to some extent a continental hinge, connecting Eastern Europe and the Pontic steppe, to the Near East. The Arab Muslims pushed north of the Caucasus, and came into conflict with the Khazars, while Cimmerians and Scythians moved south from the Pontic steppe.

The elephant in the room is the relevance to the “Indo-European controversy.” Colin Renfrew long ago posited that the Indo-European languages derive from West Asian farmers who expanded into Europe as early as ~9,000 years ago. A rival theory is that Indo-Europeans spread out of the Pontic steppe ~4,000 years ago. In 2015 two major papers suggested that the steppe was a major source of Indo-European expansion. Case closed? This preprint suggests perhaps not.

But we’ll get to that later. What do the results here show? The prose is a little hard to tease apart, but the major issues seem to be that in antiquity, or at least the period they’re focusing on, much of the gene flow seems to have been south (Near East) to the north (through the Caucasus, and out to the north slope). To some extent, we already knew this: the Yamna people of the Pontic steppe have “southern” ancestry from the Near East that earlier East European/Pontic people do not. In this preprint, the authors show that groups such as the Maykop of the north slope of the Caucasus carry Y haplogroups such as G2, and not the R1 lineages commonly found in the steppe. David W. suggests that this confirms that Near Eastern gene flow into the steppe was female-mediated.  This is plausible, but I would caution that Y chromosomes alone can be deceptive, due to the power of particular patrilineages. We’ll probably rely on the X chromosome to make a final judgment.

The plot below shows many of the relationships as a function of location and time. The green component is modal among “Iranian farmers,” the orange among “Anatolian farmers,” and the blue among “Western hunter-gatherers.”

A major aspect of this preprint is that it has to work hard to differentiate two Anatolian farmer-like signals: the first, from Anatolian farmers proper, and the second from the descendants of European farmers, who themselves are a mix of Anatolian farmers with a minority ancestry among the hunter-gatherers. The answers would probably be totally unintelligible if not for archaeology. It’s clear that the steppe people had contact with both European and Near Eastern farmers and that later East European groups that succeeded the Yamna were subject to reflux from Central Europe, and received European farmer ancestry.

Another curious nugget in their results is that there was early detection of both Ancestral North Eurasian (ANE) ancestry and, some East Eurasian gene flow (related to Han Chinese). One of their individuals carries the East Eurasian variant of EDAR, which today is only found in Finns, though it was found in reasonable frequencies among the Motala hunter-gatherers of Scandinavia. Additionally, Fu et al. 2016 found that the ancestors of Mesolithic hunter-gatherers received some gene flow from Eastern Eurasians as well (also in the supplements of Lazaridis et al. 2016).

The authors admit that there is probably population structure among ANE and undiscovered groups of East Eurasians who were traversing the Inner Asian landscape. I think this is all suggestive of some long-distance contacts, though the intensity and magnitude increased a lot with high-density societies and the mobility of pastoralism.

Much of the genetic mixing in the Near East, and to some extent in the trans-Caucasian region, seems to date to the 4th millennium. This is technically prehistory, but it is also the Uruk period. This was a phase of Mesopotamian culture expansion between 4000 and 3100 BC which resulted in replicas of Uruk style settlements as far away as Syria and southeastern Anatolia. There is even evidence of Uruk-related migration to the North Caucasus.

The Uruk experienced abrupt and sudden collapse. Uruk settlements outside of the core zone of Mesopatamia disappear.

It’s the final paragraph that warrants discussion:

The insight that the Caucasus mountains served not only as a corridor for the spread of CHG/Neolithic Iranian ancestry but also for later gene-flow from the south also has a bearing on the postulated homelands of Proto-Indo-European (PIE) languages and documented gene-flows that could have carried a consecutive spread of both across West Eurasia…Perceiving the Caucasus as an occasional bridge rather than a strict border during the Eneolithic and Bronze Age opens up the possibility of a homeland of PIE south of the Caucasus, which itself provides a parsimonious explanation for an early branching off of Anatolian languages. Geographically this would also work for Armenian and Greek, for which genetic data also supports an eastern influence from Anatolia or the southern Caucasus. A potential offshoot of the Indo-Iranian branch to the east is possible, but the latest ancient DNA results from South Asia also lend weight to an LMBA spread via the steppe belt…The spread of some or all of the proto-Indo-European branches would have been possible via the North Caucasus and Pontic region and from there, along with pastoralist expansions, to the heart of Europe. This scenario finds support from the well attested and now widely documented ‘steppe ancestry’ in European populations, the postulate of increasingly patrilinear societies in the wake of these expansions (exemplified by R1a/R1b), as attested in the latest study on the Bell Beaker phenomenon….

But instead of tackling this let’s focus on the paper that came out of the Willerslev group, The first horse herders and the impact of early Bronze Age steppe expansions into Asia. This is a final manuscript in Science. That means it was probably written before The Genomic Formation of South and Central Asia. When it comes to South Asia, the results from the two publications are consanant. There is no conflict.*

More interesting are the results in West Asia, and the linguistic supplement. In the authors note that tablets now indicate an Indo-Aryan presence in Syria ~1750 BC. Second, Assyrian merchants record Indo-European Hittite, or Nesili (the people of Nesa), as early as ~2500 BC.

As suggested in earlier work Hittite remains don’t suggest steppe influence. David W. says:

The apparent lack of steppe ancestry in five Hittite-era, perhaps Indo-European-speaking, Anatolians was interpreted in Damagaard et al. 2018 as a major discovery with profound implications for the origin of the Anatolian branch of Indo-European languages.

But I disagree with this assessment, simply because none of these Hittite-era individuals are from royal Hittite, or Nes, burials. Hence, there’s a very good chance that they were Hattians, who were not of Indo-European origin, even if they spoke the Indo-European Hittite language because it was imposed on them.

The main aspect I’d bring up with this is that in other areas steppe ancestry has spread deeply and widely into the population, including non-Indo-European ones. It is certainly possible that the sample is not needed enough to pick up the genuinely Hittite elite, but I probably lean to the likelihood that the steppe signal won’t be found. It seems that the Anatolian languages were already diversified by ~2000 BC, and perhaps earlier. Linguists have long suggested that they are the outgroup to other Indo-European languages, though this could just be a function of their isolation among highly settled and socially complex populations.

Two alternative models present themselves for these results. The Anatolian Indo-European languages expanded through elite diffusion,  part of the same general migrations that emerged out of the Yamna culture ~3000 BC. The lack of a steppe signal may be due to sampling bias, as David W. suggested, or, more likely in my opinion, simple dilution of the signal. Second, the steppe migrations were one part of a broader palette of population movements and cultural diffusions, and the Anatolian Indo-Europeans are basal to the efflorescence of the steppe derived branches.

The evidence of the explosion of Indo-Aryans in the years after 2000 BC in West and South Asia, as well as the expansion of Iranians across vast swaths of Inner Asia during the same period, suggest to me that Indo-Iranians are most definitely part of the steppe pulse. The connection to the Sintashta charioteers presents itself, and, connections to the Uralic languages indicates incubation in the trans-Volga region.

In West Asia, the Indo-Aryans crashed themselves against the most advanced civilizations of their time. Like the Bulgars, and unlike the Hittites, Indo-Aryan Mitanni was totally absorbed by their non-Indo-European Hurrian substrate. Indo-Aryan linguistic influence was preserved in their names, their gods, and in particular words relating to chariots. And yet in 2017’s Continuity and Admixture in the Last Five Millennia of Levantine History from Ancient Canaanite and Present-Day Lebanese Genome Sequences, the authors observe:

We next tested a model of the present-day Lebanese as a mixture of Sidon_BA and any other ancient Eurasian population using qpAdm. We found that the Lebanese can be best modeled as Sidon_BA 93% ± 1.6% and a Steppe Bronze Age population 7% ± 1.6% (Figure 3C; Table S6). To estimate the time when the Steppe ancestry penetrated the Levant, we used, as above, LD-based inference and set the Lebanese as admixed test population with Natufians, Levant_N, Sidon_BA, Steppe_EMBA, and Steppe_MLBA as reference populations. We found support (p = 0.00017) for a mixture between Sidon_BA and Steppe_EMBA which has occurred around 2,950 ± 790 ya (Figure S13B).

This needs to be more explored. The admixture could have come from many sources. I am curious about the frequency of R1a1a-z93 among modern-day Syrians and Lebanese.

For me these arguments can only be resolved with a deeper understanding of linguistic evolution. The close relationship of Indo-Aryan and Iranian languages is obvious to any speaker of either of these languages (I can speak some Bengali). A divergence in the range of 4 to 5 thousand years before the present seems most likely to me. But the relationship of the other Indo-European languages is much less clear.

One of the arguments in Peter Bellwood’s First Farmers is that the Indo-European languages exhibit a “rake-like” topology with the exception of Indo-Iranian, which forms a clear clade. To him and others in his camp, this argues for deep divergences very early in time.

It is hard to deny that the steppe migrations between 4 and 5 thousand years ago had something to do with the distribution of modern Indo-European languages. But, it is harder to falsify the model that there were earlier Indo-European migrations, perhaps out of the Near East, that preceded these. Only a deeper understanding of linguistic evolution, and multidisciplinary analysis of regional substrates will generate the clarity we need.

* I’m going to skip the Botai angle in this post.

November 12, 2017

Near Prehistory in Northern Europe was an Indo-European world

Filed under: Indo-European,Indo-Europeans — Razib Khan @ 9:01 pm

Near Prehistory in Northern Europe was an Indo-European worldThe Picts were the topic of discussion on this week on In Our Time. They are a mysterious yet intriguing people because we don’t know much about them in their own words, but, they are one of the roots of modern Scottish identity. When I first encountered the Picts decades ago there was some debate as to whether they were a pre-Indo-European people or not. Today that seems to not be a hypothesis people entertain. Rather, the Picts were simply the least Romanized of the Brythonic Celtic people of Britain.

Today because of the genetic data I think we can be rather confident that by the time of the Roman Empire there were no non-Indo-Europeans left in Northern Europe. The Beaker people in Britain and Ireland seem to have overwhelmingly replaced the native population of farmers, whose ancestors had predominantly arrived from the eastern Mediterranean thousands of years ago (via the Atlantic littoral or Central Europe). Across Northern Europe, in general, the replacement of the previous populations was substantial, though not total.

In Southern Europe, the arrival of Indo-Europeans was more fitful, and persistence of Basque attests to the fact that non-Indo-European languages were spoken down to historical times (if Etruscan is considered native to the Italian peninsula, that’s another example, though this is hotly debated and I lean toward the exogenous model). The pre-Latin language of Sardinia was almost certainly not Indo-European, while Greek has a high proportion of non-Indo-European words in its lexicon.

 

June 24, 2017

Indian genetics, part n of many

Filed under: ancient india,History,Indo-Europeans — Razib Khan @ 2:59 pm

I put up close to definitive piece for me in relation to South Asian historical population genetics. At least until new research is published. I did leave out some stuff about my own vague thoughts…but I think the takeover of Hattian and Hurrian cultures by the Nesha (Hittites) and Haryannu (Mitanni) have something to teach us….

June 19, 2017

Indian genetics, the never-ending argument

Filed under: Genetics,India,Indian Genetics,Indo-Europeans,science — Razib Khan @ 10:44 pm

I am at this point somewhat fatigued by Indian population genetics. The real results are going to be ancient DNA, and I’m waiting on that. But people keep asking me about an article in Swarajya, Genetics Might Be Settling The Aryan Migration Debate, But Not How Left-Liberals Believe.

First, the article attacks me as being racist. This is not true. The reality is that the people who attack me on the Left would probably attack magazines like Swarajya as highly “problematic” and “Islamophobic.” They would label Hindu nationalism as a Nazi derivative ideology. People should be careful the sort of allies they make, if you dance with snakes they will bite you in the end. Much of the media lies about me, and the Left constantly attacks me. I’m OK with that because I do believe that the day will come with all the ledgers will be balanced. The Far Left is an enemy of civilization of all stripes. I welcome being labeled an enemy of barbarians. My small readership, which is of diverse ideologies and professions, is aware of who I am and what I am, and that is sufficient. Either truth or power will be the ultimate arbiter of justice.

With that out of the way, there this one thing about the piece that I think is important to highlight:

To my surprise, it turned out that that Joseph had contacted Chaubey and sought his opinion for his article. Chaubey further told me he was shocked by the drift of the article that appeared eventually, and was extremely disappointed at the spin Joseph had placed on his work, and that his opinions seemed to have been selectively omitted by Joseph – a fact he let Joseph know immediately after the article was published, but to no avail.

Indeed, this itself would suggest there are very eminent geneticists who do not regard it as settled that the R1a may have entered the subcontinent from outside. Chaubey himself is one such, and is not very pleased that Joseph has not accurately presented the divergent views of scholars on the question, choosing, instead to present it as done and dusted.

I do wish Tony Joseph had quoted Gyaneshwer Chaubey’s response, and I’d like to know his opinions. Science benefits from skepticism. Unfortunately though the equivocation of science is not optimal for journalism, so oftentimes things are presented in a more stark and clear manner than perhaps is warranted. I’ve been in this position myself, when journalists are just looking for a quote that aligns with their own views. It’s frustrating.

There are many aspects of the Swarajya piece I could point out as somewhat weak. For example:

The genetic data at present resolution shows that the R1a branch present in India is a cousin clade of branches present in Europe, Central Asia, Middle East and the Caucasus; it had a common ancestry with these regions which is more than 6000 years old, but to argue that the Indian R1a branch has resulted from a migration from Central Asia, it should be derived from the Central Asian branch, which is not the case, as Chaubey pointed out.

The Srubna culture, the Scythians, and the people of the Altai today, all bear the “Indian” branch of R1a. First, these substantially post-date 6000 years ago. I think that that is likely due to the fact that South Asian R1a1a-Z93 and that of the Sbruna descend from a common ancestor. But in any case, the nature of the phylogeny of Z93 indicates rapid expansion and very little phylogenetic distance between the branches. Something happened 4-5,000 years ago. One could imagine simultaneous expansions in India and Central Asia/Eastern Europe. Or, one could imagine an expansion from a common ancestor around that time. The latter seems more parsimonious.

Additionally, while South Asians share ancestry with people in West Asia and Eastern Europe, these groups do not have distinctive South Asian (Ancestral South Indian) ancestry. This should weight out probabilities as to the direction of migration.

Second, I read some of the papers linked to in the article, such as Shared and Unique Components of Human Population Structure and Genome-Wide Signals of Positive Selection in South Asia and Y-chromosomal sequences of diverse Indian populations and the ancestry of the Andamanese. The first paper has good data, but I’ve always been confused by the interpretations. For example:

A few studies on mtDNA and Y-chromosome variation have interpreted their results in favor of the hypothesis,70–72 whereas others have found no genetic evidence to support it.3,6,73,74 However, any nonmarginal migration from Central Asia to South Asia should have also introduced readily apparent signals of East Asian ancestry into India (see Figure 2B). Because this ancestry component is absent from the region, we have to conclude that if such a dispersal event nevertheless took place, it occurred before the East Asian ancestry component reached Central Asia. The demographic history of Central Asia is, however, complex, and although it has been shown that demic diffusion coupled with influx of Turkic speakers during historical times has shaped the genetic makeup of Uzbeks75 (see also the double share of k7 yellow component in Uzbeks as compared to Turkmens and Tajiks in Figure 2B), it is not clear what was the extent of East Asian ancestry in Central Asian populations prior to these events.

Actually the historical and ancient DNA evidence both point to the fact that East Asian ancestry arrived in the last two thousand years. The spread of the first Gokturk Empire, and then the documented shift in the centuries around 1000 A.D. from Iranian to Turkic in what was Turan, signals the shift toward an East Asian genetic influx. Alexander the Great and other Greeks ventured into Central Asia. The people were described as Iranian looking (when Europeans encountered Turkic people like Khazars they did note their distinctive physical appearance).

We have ancient DNA from the Altai, and those individuals initially seemed overwhelmingly West Eurasian. Now that we have Scythian ancient DNA we see that they mixed with East Asians only on the far east of their range.

The second paper is very confused (or confusing):

The time divergence between Indian and European Y-chromosomes, based on the closest neighbour analysis, shows two different distinctive divergence times for J2 and R1a, suggesting that the European ancestry in India is much older (>10 kya) than what would be expected from a recent migration of Indo-European populations into India (~4 to 5 kya). Also the proportions suggest the effect might be less strong than generally assumed for the Indo-European migration. Interestingly, the ANI ancestry was recently suggested to be a mix of ancestries from early farmers of western Iran and people of the Bronze Age Eurasian steppe (Lazaridis et al. 2016). Our results agree with this suggestion. In addition, we also show that the divergence time of this ancestry is different, suggesting a different time to enter India.

Lazaridis et al. accept a mass migration from the steppe. In fact, the migration is to such a magnitude that I’m even skeptical. Also, there couldn’t have been a European migration to South Asia during the Pleistocene because Europeans as we understand them genetically did not exist then!!!

I assume that many of the dates of coalescence are sensitive to parameter conditions. Additionally, they admit limitations to their sampling.

Ultimately the final story will be more complex than we can imagine. R1a is too widespread to be explained by a simple Indo-Aryan migration in my opinion. But we can’t get to these genuine conundrums if we keep having to rebut ideologically motivated salvos.

Related: Ancient herders from the Pontic-Caspian steppe crashed into India: no ifs or buts. I wish David would be a touch more equivocal. But I have to admit, if the model fits, at some point you have to quit.

April 4, 2017

How a Eurasian “band of brothers” shaped the world

Filed under: Anthroplogy,Corded Ware,History,Indo-Europeans — Razib Khan @ 1:10 pm

How a Eurasian “band of brothers” shaped the world
How a Eurasian “band of brothers” shaped the worldWhen I was eight years old I saw a map which genuinely confused me. I had opened up deluxe dictionary at my elementary school and saw a map of the world’s language families, and noticed that there were a group of dialects which spanned the Bay of Bengal to the North Sea. In fact, according to this map the language I had first learned to speak, Bengali, was in the same language family as English.

This was hard to wrap my mind around, but there it was in front of me. Further research at the public library confirmed this fact. And, upon further reflection it was obvious to me there were similarities…I had been learning French at school, and English, Bengali, and French, all exhibited similarities in the first ten numbers. English and French I understood in terms of a natural relationship, but Bengali?

My personal and professional interests have never been in domains where I would explore the topic first hand, but the origins of Indo-European languages have always been a hobby. I read books such as The Horse, the Wheel, and Language and In Search of the Indo-Europeans when I could. When taking in excellent works such as Empires of the Silk Road the Indo-European thread was always something I kept in mind.

How a Eurasian “band of brothers” shaped the worldBut the above works take a more old-fashioned Eurasian heartland “marauders from the steppe” viewpoint. Starting about 15 years ago I began to look into a different framework: Indo-Europeans as farmers. For me begins with the 2002 paper, Mapping the Origins and Expansion of the Indo-European Language Family, which finds that “the inferred timing and root location of the Indo-European language trees fit with an agricultural expansion from Anatolia beginning 8000 to 9500 years ago” (this is the last paper I can remember reading in paper format). The model is elaborated by Peter Bellwood in works such as First Farmers, though he applies it to most language families.

But its origins go back decades, with the archaeologist Colin Renfrew. Rather than dramatic explosions from the steppe, Renfrew and colleagues suggest that the demographic expansion enabled by agriculture as a mode of production allowed for groups like Indo-Europeans to rapidly swamp their neighbors and enter into a process known as a wave of advance. There wasn’t a organized movement. Rather, farming enables the growth of population to such an extent that it was almost an undirected thermodynamic law that the original farmers would radiate outward, away from zones at the Malthusian carrying capacity and out toward virgin land.

It was a parsimonious theory, and phylogenetic techniques seem to have supported it. But then came ancient DNA to overturn the apple-cart. I won’t reshash what you probably already know, but will point to the two most relevant papers, Massive migration from the steppe was a source for Indo-European languages in Europe and Population genomics of Bronze Age Eurasia. Basically there was massive population turnover during the early Bronze Age. The genetic data aligned well with predictions you’d make from the old “marauders from the steppe” model, not the demic diffusion of farmers who were subject to high endogenous population growth over time.

Of course the Anatolian model proponents have an answer. There is a thesis whereby the steppe pastoralists derive from Anatolians, and so the European population turnover was of one Indo-European group by another. This is possible, but to my knowledge this model was never foregrounded by Anatolianists before. Rather, it strikes me as a way to “save” their framework.

So far much of the battle has been between archaeologists, who tend to favor gradualism, and often even  cultural diffusion as opposed to migration, and historical linguists and arriviste geneticists, who tend toward a more classical migration-from-the-steppe perspective.

A new paper in Antiquity takes the sledgehammer to the Anatolian hypothesis with an archaeology first tack. Re-theorising mobility and the formation of culture and language among the Corded Ware Culture in Europe. They don’t pull punches:

…the Anatolian hypothesis must be considered largely falsified. Those Indo-European languages that later came to dominate in western Eurasia were those originating in the migrations from the Russian steppe during the third millennium BC.

Why would they say this? There is a major paper coming out:

These local processes of social integration between intruding Yamnaya/Corded Ware populations and remnant Neolithic populations can be applied to language dispersal. We should expect that the transformation from Proto-Indo-European to Pre-Proto Germanic would reveal the same kind of hybridisation between an earlier Neolithic language of the Funnel Beaker Culture, and the incoming Proto-Indo-European language. This is precisely what recent linguistic research has been able to demonstrate (Kroonen & Iversen in press). In their study on the formation of Proto-Germanic in Northern Europe, Kroonen and Iversen document a bundle of linguistic terms of non-Indo-European origin linked to agriculture that were adopted by Indo-European-speaking groups who were not fully fledged farmers.

How a Eurasian “band of brothers” shaped the worldThey also contend that the Neolithic language was roughly the same throughout the zone of Indo-European expansion. From what those who would know about these sorts of things have told me this is plausible, because the Neolithic farmers spread so rapidly from a small founder culture, and exhibited broad Europe-wide similarities for a thousand years. Curiously, the chart shows that Germanic languages may have been influenced by a hunter-gatherer language, which the others were not. I suspect this may have to do with the relatively late persistence of hunter-gatherers in some maritime environments facing the Baltic and North Sea.

The paper, which is open access, needs to be read in full. Here are some important points:

  • Burial type seems to be a more robust form of indicator of dominant cultural identity
  • Corded Ware males practiced exogamy
  • Corded Ware males traveled long distances
  • Corded Ware culture was initially exclusively pastoralist
  • There is a great deal of circumstantial, and some genetic, evidence that Corded Ware communities were characterized by having women who were clearly from the Neolithic farming population
  • There was intergroup violence as a function of culture
  • The Corded Ware and Neolithic populations persisted near each other geographically, though the Neolithic groups seem to have retreated to uplands
  • The Corded War engaged in a wholesale pattern of landscape sculpting, burning down forests to produce pasture

Neolithic Y lineages, such as G2, are far rarer in Northern Europea today that R1a and R1b (in contrast, the hunter-gatherer I seems to have gone through an expansion just like R1a and R1b). We already have a model for what went on here, the Iberian settlement of the New World. Among mestizo populations there are huge skews of mtDNA and Y, with the former almost all Amerindian (with some African) and the latter almost all European (with some African).

The Corded War are the ancestors of the German peoples who we see emerge into the light of history during antiquity. What these data are telling is that the Germans are the product of a massive period of biological and cultural amalgamation and synthesis between indigenous groups and intrusive populations from the steppe. The archaeological data indicate that the intrusion was male mediated. The “battle axe” culture probably lived up to its name. And they weren’t likely exceptional….

September 10, 2012

The West Asian mix

Filed under: Genetics,Indo-Europeans — Razib Khan @ 7:42 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.

The West Asian mix

August 16, 2012

Rise of the planet of the Indo-Europeans

Filed under: Anthroplogy,History,Indo-Europeans — Razib Khan @ 9:00 am

Rise of the planet of the Indo-Europeans

In response to my post below a friend emailed me the above sentence. As I suggest below it sounds crazy, and I don’t know if I believe it. But here’s an abstract from the Reich lab from June:

Estimating a date of mixture of ancestral South Asian populations

Linguistic and genetic studies have demonstrated that almost all groups in South Asia today descend from a mixture of two highly divergent populations: Ancestral North Indians (ANI) related to Central Asians, Middle Easterners and Europeans, and Ancestral South Indians (ASI) not related to any populations outside the Indian subcontinent. ANI and ASI have been estimated to have diverged from a common ancestor as much as 60,000 years ago, but the date of the ANI-ASI mixture is unknown. Here we analyze data from about 60 South Asian groups to estimate that major ANI-ASI mixture occurred 1,200-4,000 years ago. Some mixture may also be older—beyond the time we can query using admixture linkage disequilibrium—since it is universal throughout the subcontinent: present in every group speaking Indo-European or Dravidian languages, in all caste levels, and in primitive tribes. After the ANI-ASI mixture that occurred within …

July 15, 2012

Continuing the search for Indo-Europeans

Filed under: History,Indo-Europeans — Razib Khan @ 1:53 pm

Dienekes P. is often rather laconic in commentary on the papers he links to, but of late he has “come out of his shell.” He has two posts which are important “weekend reading”:

Population strata in the West Siberian plain (Baraba forest steppe)

Hints of East/Central Asian admixture in Northern Europe

I freely admit that much of the conjecture here is above my pay-grade in terms of evaluation. But I do think it’s important think through. My “gut” tends to lean toward a “revenge of the Mesolithic” scenario promoted by some of Dienekes’ critics, but I don’t have a strong position.

Continuing the search for Indo-Europeans

July 3, 2012

Has Dienekes Pontikos found the signature of the Indo-Europeans?

Filed under: Anthroplogy,History,Indo-Europeans,Linguistics — Razib Khan @ 12:35 pm

I don’t know the answer to the question posted in title above, and I’m moderately skeptical that he has. But I wanted to give him full credit in the public record if researchers confirm his findings in the next few years. You can read the full post at his weblog, but basically he found that a West Asian modal element in a north British (Orkney) and Lithuanian individual seems to be negatively correlated with a Northwest European modal element and positively correlated with Near Eastern and South Asian components on a genomic level across different models in ADMIXTURE (e.g., does “South Asian” at K = 5 tend to match “West Asian” at K = 8).

Two major concerns:

– I don’t have a good intuition for this method. Could this be an artifact of the algorithm?

When you have a hypothesis in mind you can unconsciously seek out confirmatory points. As you can see in the comments below Dienekes and his interlocutors have given this issue much thought. Frankly, I found it difficult to follow a lot of the dialogue, and I follow this topic more than most.

It seems that at this point someone should do follow up analyses …Has Dienekes Pontikos found the signature of the Indo-Europeans?

July 1, 2012

The mystery of the origin of the Indo-Europeans may be solved within the next 2 years

Filed under: Anthroplogy,Indo-Europeans — Razib Khan @ 12:27 pm

Dienekes has a post up, The Bronze Age Indo-European invasion of Europe. The crux of his argument is as such:

But there is another component present in modern Europe, the West_Asian which is conspicuous in its absence in all the ancient samples so far. This component reaches its highest occurrence in the highlands of West Asia, from Anatolia and the Caucasus all the way to the Indian subcontinent. It is well represented in modern Europeans, reaching its minima in the Iberian peninsula….

Thanks to the public release of genetic data Dienekes has developed his theories in part out of his own analyses of said data. Though I’ve run fewer analyses, with smaller data sets, some of the same patterns jump out at me. In particular, there is a component which is modal in northern West Asia (e.g., the trans-Caucasian region) which seems to drop mysteriously between the French generally and French Basques, and the Basque vs. non-Basque Spanish samples. There are also similar, though not necessarily easy to map across the two regions, disjunctions in South Asia between geographically close Indian groups.

Ultimately model-based clustering algorithms and PCA is going to get us only so far. Remember that the clusters generated …The mystery of the origin of the Indo-Europeans may be solved within the next 2 years

December 16, 2011

How to reconstruct the Indo-Europeans

As must be obvious, I think now that the spread of Indo-European languages had some demographic impact. It wasn’t analogous to the spread of English to Jamaica, or the existence of French as an official language in Congo-Brazzaville. Because of this, I now believe it is possible in the near future that scientists will reconstruct the genome of the original Indo-Europeans. How?

1) Find the intersection of genetic segments on the chromosomal level which share identity-by-descent between widely separated Indo-European groups. For example, Greeks, Swedes, and Punjabis.

2) Check to see which of these intersecting elements is not found in nearby non-Indo-European groups. For example, Basques, Finns, and non-Brahmin South Indian Dravidian speakers. At least to an appreciable frequency.

My current supposition is that proportionally this component won’t be preponderant in most places, but, it will be significant. By reconstructing an Indo-European genome we may actually have the ability to ascertain the population’s urheimat, as we can compare its genetic distance to extant populations.

How to reconstruct the Indo-Europeans

June 27, 2011

First Farmers Facing the Ocean

First Farmers Facing the Ocean

The image above is adapted from the 2010 paper A Predominantly Neolithic Origin for European Paternal Lineages, and it shows the frequencies of Y chromosomal haplogroup R1b1b2 across Europe. As you can see as you approach the Atlantic the frequency converges upon ~100%. Interestingly the fraction of R1b1b2 is highest among populations such as the Basque and the Welsh. This was taken by some researchers in the late 1990s and early 2000s as evidence that the Welsh adopted a Celtic language, prior to which they spoke a dialect distantly related to Basque. Additionally, the assumption was that the Basques were the ur-Europeans. Descendants of the Paleolithic populations of the continent both biologically and culturally, so that the peculiar aspects of the Basque language were attributed by some to its ancient Stone Age origins.

As indicated by the title the above paper overturned such assumptions, and rather implied that the origin of R1b1b2 haplogroup was in the Near East, and associated with the expansion of Middle Eastern farmers from the eastern Mediterranean toward western Europe ~10,000 years ago. Instead of the high frequency of R1b1b2 being a confident peg for the …

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