Genetics and archaeogenetics of South Asia

"In reading the genetics literature on South Asia, it is very clear that many of the studies actually start out with some assumptions that are clearly problematic, if not in some cases completely untenable. Perhaps the single most serious problem concerns the assumption, which many studies actually start with as a basic premise, that the Indo-Aryan invasions are a well-established (pre)historical reality. The studies confirm such invasions in large part because they actually assume them to begin with."

"[T]he present-day linguistic affinities of different Indian populations per se are perhaps among the most ambiguous and even potentially controversial lines of evidence in the reconstruction of prehistoric demographic processes in India."

"Most genetic studies are built on unstated, unproven (and often unwitting) assumptions: not only that migration is the supreme mechanism to account for the spread of genes and languages, but also that, in India’s case, the said genes could only have spread unidirectionally. The studies then proceed to marshal evidence to ‘prove’ the assumption, in a classic case of circularity."

"South Asia has indeed been at the crossroads for much of modern human prehistory."

"Confusing language movements with demographic movements was a childhood disease of Indo-European linguistics before 1945. Especially after Charles Darwin’s Origin of Species (1859), race thinking came to dominate the Humanities. There were warnings from Indo-Europeanists, including the much-maligned Friedrich Max Müller, to maintain the distinction, but the public and many professionals started speaking of “the Aryan race”, not in the vague sense common earlier (race = any group of hereditary belonging, from family to nation and race to humanity, Sanskrit jāti), but in the biological sense. After 1945, this went completely out of fashion in the West, but in India, not encumbered with the guilt about Nazi racism, time has stood still."

"Nothing in the osteometric data shows that relationships existed between the populations of the Oxus Civilization and those of the steppes: these populations are separate, different. This would prove that if there were migrations, they were not significant at that time. Mixtures of steppe and oasis populations do not become significant until the time when corpses disappear through cremation or exposure."

"Unfortunately, genetic studies sometimes draw conclusions about language, which is entirely incorrect. Genetics addresses the history of a population’s formation, including migration to new regions, mixing with other populations, and the processes involved—but nothing beyond that... A similar situation arises in palaeogenetics, where study results indicate that the population of the Indian subcontinent formed from neighboring substrates, yet the conclusions still incorporate the steppe homeland hypothesis. This notion may have delayed a successful resolution of the problem for many decades. It is necessary to establish a framework in which archaeological, palaeogenetic, and linguistic data do not contradict one another, as occurs with the Steppe theory. Since this is primarily a linguistic problem, the starting point should be language."

"Only 5% of the Y chromosomes of the R1a-Z93 subtype that occurs at 100% frequency in the steppe population are present in the Swat Valley population. Therefore, it is assumed that women were incorporated there. But if we assume that this population was responsible for 30% of the Indian population, a possible proportion of steppe genes decreases to 6-7% and the proportion of male chromosomes become infinitesimal... However, with such a low male contribution, even for the population of the Swat Valley, language change is doubtful, so it is an almost unbelievable proposition for India... [A]gainst the background of the lack of archaeological and genetic data on mass migration to the region with a high population density, it is more logical to assume that the ancestors of the North Indians lived somewhere close to South Asia."

"The data provide no support for any model of massive migration and gene flow between the oases of Bactria and the Indus Valley. Rather, patterns of phenetic affinity best conform to a pattern of long-standing, but low-level bidirectional mutual exchange."

"As for the question of biological continuity within the Indus Valley, two discontinuities appear to exist. The first occurs between 6000 and 4500 BC [with another discontinuity] at some point after 800 BC but before 200 BC. In the intervening period, [the data] reveals clear indications of interaction with the West and specifically with the Iranian Plateau."

"Overall percentages [of steppe ancestry] are generally very low, and in South Asia also too late for a plausible first arrival of Indic languages here (let alone Indo-Iranic as a whole). But however small and late, and however implausible that they replaced all languages from Iran right across to northern India, that is what has to be claimed for these weak signals, for the Steppe hypothesis to be right."

"[The ancient Harappans] are not markedly different in their skeletal biology from the present-day inhabitants of Northwestern India and Pakistan... Of the Aryans, we must defer to literary and linguistic scholars in whose province lies the determination of the arrival and nature of the linguistic phenomenon we call the Aryans. . . . But archaeological evidence of Aryan-speaking peoples is questionable and the skeletal evidence is nil."

"In short, there is no evidence of demographic disruptions in the northwestern sector of the subcontinent during and immediately after the decline of the Harappan culture... All prehistoric human remains recovered thus far from the Indian subcontinent are phenotypically identifiable as ancient South Asians... How could one recognize an Aryan, living or dead, when the biological criteria for Aryanness are non-existent?"

"For me and for Toomas Kivisild, South Asia is logically the ultimate origin of M17 and his ancestors; and sure enough we find the highest rates and greatest diversity of the M17 line in Pakistan, India, and eastern Iran, and low rates in the Caucasus. M17 is not only more diverse in South Asia than in Central Asia, but diversity characterizes its presence in isolated tribal groups in the south, thus undermining any theory of M17 as a marker of a ‘male Aryan invasion’ of India. One average estimate for the origin of this line in India is as much as 51,000 years. All this suggests that M17 could have found his way initially from India or Pakistan, through Kashmir, then via Central Asia and Russia, before finally coming into Europe."

"So, in the migration scenario females with steppe-related ancestry move down across the [Indus] by the end of the bronze age and this leads to the formulation of the “patriarchal-steppe-warrior-chariot” bronze age hymns somehow in iron age India? And Iranians ... somehow manage to compose the Avesta before the Iranians migrate to western Iran and somehow the Medes and Persians separate around 1000 BCE. Also, by some miracle, the Mitanni reached West Asia around 1760 BCE. This is simply impossible."

"The anthropologists who have recently described the skeletons from Harappa remark that there, as at Lothal, the population would appear, on the available evidence, to have remained more or less stable to the present day."

"Genetic variation in contemporary South Asian populations follows a northwest to southeast decreasing cline of shared West Eurasian ancestry."