The Aryan Invasion Was Not Fantasy

51IQSePVDRL._SY344_BO1,204,203,200_If there is one Peter Heather book you should read because it is timely, it is Empires and Barbarians: The Fall of Rome and the Birth of Europe. In it Heather makes an apologia for a revisionist view which resurrects some aspects of the old folk migration theories, and understandings of the arrival of barbarians into the collapsing Roman order of the middle of the first millennium. This is in contrast to the conventional view of modern archaeologists and historians which posits that the barbarian invasion was more a change of power to the elites, with the emergence of ethnic identities and coalitions almost in an ad hoc fashion among groups of mercenaries who took control from their paymasters. Heather does not posit total replacement of the indigenous population. In fact, it turns out in the best case scenario for such an event, in what became Anglo-Saxon England, the genetic data does not support such a proposition. Rather, there was an amalgamation between a culturally dominant intrusive minority, and the indigenous majority. The evidence from the rest of Western Europe is much more equivocal, suggesting that the demographic impact of the barbarians was minor (this not the case in Eastern Europe, where the Slavic migrations are associated with signals of strong genetic correlations between recently settled populations in the wake of German and Roman declines on the eastern frontier).

Heather’s position is really one of moderation or the Golden Mean. It is rather like those who do not take a pure hereditarian or environmentalist position in behavior genetics. In Empires and Barbarians he marshals evidence which points to the reality that the barbarian groups entered the Empire as self-conscious tribal-ethnic entities, with whole families on the move, and that they were not created de novo within the Empire. This is not to deny the reality of cultural shifts in identity, with Roman elites in Gaul taking to trousers and referring to themselves as “Franks,” and German tribal leaders attempting to accrue to themselves the glamour and respectability of Romanitas. But the fundamental identities which are combined were distinct, and organic, not recently constructed and inchoate.

51sBGrYcIEL._SY344_BO1,204,203,200_The most recent work from ancient DNA, which I wrote about extensively this weekend, support Heather’s contentions broadly, if not specifically. The evidence from prehistory indicates far more demographic disruption than during the fall of the Roman Empire. That is, folk wanderings were much more significant in prehistory than in antiquity. That probably has to due social-demographic changes that occurred in the first millennium before the Common Era, as ruling elites became decoupled from the population they ruled in many ways, though often bound together by a religious ethos. The fusion of the conquered and conquerors was a process made much more feasible by the emergence of “meta-ethnic”, to use Peter Tuchin’s terminology, religious ideologies which transcended folk boundaries.

The reality of new facts means that we need to reinterpret aspects of archaeology and myth in terms of the dynamics which are reflected by our new understanding. One side aspect of my writings on these topics is that many Indians are not very happy with the newest results, because they validate threads of a frankly colonialist model of an Indo-Aryan invasion. The model is that a European-like population invaded the Indian subcontinent, imposed the caste system, and imparted many aspects of high culture upon the natives. Despite racial mixture between the indigenous and intrusive elements, the higher castes and peoples of the Northwest had more Aryan ancestry.

This model wasn’t totally a figment of the British colonialist imagination, and had much to do with the discovery of the connection between Sanskrit and other Indo-European languages, such as ancient Greek and Latin. Yes, the theory was utilized for political ends, but the model itself reflects some factual realities on the ground. For reasons which I will not elaborate in detail, because I don’t know that much about it, and don’t care either, a dominant strand of Indian nationalism has turned against the Indo-Aryan model of intrusion. In fact this school has “flipped the script,” asserting that Indo-Aryans, and therefore Indo-European languages, are indigenous to the subcontinent.

Linguistic sanity indicated that this was always unlikely. But the idea that most of the ancestry of South Asians dates to the last Ice Age, that is, the Indo-Aryan invasion was demographically marginal, was a defensible position until recently. For example, in 2006 you have  a paper such as Polarity and Temporality of High-Resolution Y-Chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists. Additionally, as individuals have pointed out to me ad nauseam, archaeologists are skeptical of mass migration because of lack of remains.

R Graphics OutputFirst, a paper from 2006 is wildly out of date for this field. The methods used have been superseded. Instead of using one locus, the Y chromosome, and focusing on microsatellites (which have upsides and downsides), researchers now look at the whole genome. Probably the best paper to read on the latest results is Genetic Evidence for Recent Population Mixture in India. The authors date the admixture between two different lineages in the subcontinent to “1,900 to 4,200 years ago.” One of the lineages is rather like West Asians and Europeans genetically (ANI). The other is most closely related to Andaman Islanders (ASI), but diverged from this group on the order of 20 thousand years ago. It can be accurately stated the the ASI are part of a broader constellation of East Eurasian populations which diverged from West and North Eurasians 40 thousand years ago (and from Basal Eurasians even earlier). In other words, modern South Asians are a compound of two highly diverged lineages, which explains their ambiguous position in relation to West and East Eurasian “reference” groups. And, this fact means teasing apart the ancestry is relatively easy, though time elapsed means that for all practical purposes South Asians are now a cluster of their own in any analysis of human population structure (that is, though they can be decomposed into parental elements, that’s not practical or useful in most cases).

Screenshot - 06152015 - 01:39:27 PMAnd, not surprisingly, the ratio of the ANI/ASI ancestry varies as a function of caste and region. This is the hallmark of relatively recent admixture, maintained by social barriers in caste. Indian caste groups (really jati) exhibit runs of homozogosity in their genome which are signs of a low effective population. In other words, not too much gene flow across groups. The direction of admixture is exactly as predicted by the old theories, as if an intrusive population arrived via the Northwest, and imposed itself upon the indigenous groups.

Now, let me address the major objections:

1) What about the mtDNA, which shows that most of South Asian ancestry is indigenous, and not West Eurasian.

Answer: The migration may have been male-mediated. All this means is that gene flow from the northwest occurred mostly through males. Over multiple iterations this can replace much of the whole genome, while leaving the single mtDNA lineage intact. This is exactly what happened in Argentina.

2) What about Y chromosomal results, which imply that R1a1a is indigenous to South Asia

Answer: Much of that work has utilized a small number of SNPs or microsatellites. The issues of phylogeography and dating for Y chromosomes are such that we really have had low clarity until whole genome analysis era, which is occurring now. The fact is that the Y chromosomal phylogeny of R1a1a the world over exhibits the hallmarks of massive population expansion ~5,000 years ago. No one knows where the R1 lineages are truly from in a deep time sense, as it seems likely they were low frequency variants before their explosion.

3) What about various aspects of mythology and archaeology which don’t posit an invasion/migration?

Answer: First, the archaeologists have a big record now of being wrong in Europe. Though many archaeologists (and historians who drew upon their scholarship) were cautious, some were not, and stridently argued that demographic replacements were not seen or evident in the archaeological record. The ancient DNA has basically proven them wrong. So either their methods miss migration, or, their results are labile when ideology is applied. Second, in regards to the lack of Indo-Aryan memory of migration, the Greeks also had no memory of migration. Both Greeks and Indians (Indo-Europeans) can not simultaneously be indigenous. Clearly oral memory has an expiration date, and may not be reliable.

Perhaps the archaeologists are totally right. I can’t evaluate their scholarship. I can evaluate the genetics, and it is getting progressively more persuasive. Scientific disciplines often have conflicts, though they are ultimately resolved (see the age of the earth controversy between geologists and biologists vs. physicists in the late 19th century). The recent track record of archaeologists has not been the best in my opinion when it comes to broader theoretical implications.

Finally, I want to state that I am skeptical, or not convinced, that most of the ANI ancestry in South Asia is from the Indo-Europeans. The ANI ancestry might be a composite, and perhaps the dominant language of the first ANI people was Dravidian. The closest populations to the ANI seem to be the people of the Caucasus, though this may be a function of changes in West Asian genetics. The Indo-Aryans may have been one of the later peoples to arrive.

Additionally, the Indo-Aryans were not blonde Europeans. Blonde Europeans seem to have evolved in Europe in situ over the past 4,000 years due to the admixture of diverse threads, indigenous and exogenous. There are elements of European ancestry (particular EEF) which do not seem to be evident in West Asia or South Asia, suggesting that the origination of Indo-European was complex, and perhaps multi-faceted. The Indo-Aryans had an affinity to the peoples of Europe, but it is a rather circuitous connection. We haven’t unpacked all the details.

Where does this leave us? There are many Indians who are like Creationists, for whom the scholarship is simply a way to buttress their ideology. They may cite the scholarship, but it is to a great extent just a matter of dressing up their nationalistic preferences. For these the new results are not only threatening, they are irrelevant. They will continue to cite papers from ~2005, because at that time period the results were more congenial to them. There are others who will “update” their views. There is much updating and revision that will occur over the next few years, and ancient DNA may change our perceptions about South Asia again. So be it.

Addendum: Wendy Doniger’s The Hindus is a controversial book. Religious fanatics and nationalists have waged a campaign against it. It is a testament of their milder nature that Doniger wrote under her real name, something that might not have happened if she was writing about Islam. I read the book when it came out, and it wasn’t my cup of tea, but I didn’t see what the big deal was (of course, why would I? I’m an irreligious atheist). But today I now think back to the passages which refer to the contact between Aryans and non-Aryans. Within these folktales and mythological memories may actually be a record of interaction which we do not in general have from Europe of “first contact” between startlingly disparate worlds.

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