When closely related individuals mate, they produce inbred offspring, which often have lower fitness than outbred ones. Geographical exogamy, by favouring matings between distant individuals, is thought to be an inbreeding avoidance mechanism; however, no data has clearly tested this prediction. Here, we took advantage of the diversity of matrimonial systems in humans to explore the impact of geographical exogamy on genetic diversity and inbreeding. We collected ethno-demographic data for 1,344 individuals in 16 populations from two Inner Asian cultural groups with contrasting dispersal behaviours (Turko-Mongols and Indo-Iranians) and genotyped genome-wide single nucleotide polymorphisms in 503 individuals. We estimated the population exogamy rate and confirmed the expected dispersal differences: Turko-Mongols are geographically more exogamous than Indo-Iranians. Unexpectedly, across populations, exogamy patterns correlated neither with the proportion of inbred individuals nor with their genetic diversity. Even more surprisingly, among Turko-Mongols, descendants from exogamous couples were significantly more inbred than descendants from endogamous couples, except for large distances (>40 km). Overall, 37% of the descendants from exogamous couples were closely inbred. This suggests that in Inner Asia, geographical exogamy is neither efficient in increasing genetic diversity nor in avoiding inbreeding, which might be due to kinship endogamy despite the occurrence of dispersal.
Two cultural groups, which matrimonial systems are reported to differ, coexist in Inner Asia: Turko-Mongols are described as mainly exogamous while Indo-Iranians are thought to be mainly endogamous45. However, it is not always clear if exogamy refers to clan (ethnic) or village (geographical) exogamy. Here, we used a dataset of 16 populations representing 11 different ethnic groups from both cultural groups and we quantified geographical exogamy rates and distances in each population. Using an empirical threshold of 4 km, we confirmed that matrimonial behaviours differ as described in the literature, even though we found some exceptions: three Turko-Mongol populations (out of 14) have less than 50% exogamy, whereas one Indo-Iranian population (out of four) has more than 50% exogamy.(…).
An additional important result of our study is that geographical distances are not negatively correlated with inbreeding, as could have been expected under an isolation-by-distance model65. Interestingly, a recent study based on a large genealogical dataset, collected across Western Europe and North America, and including birth places information, similarly found an absence of correlation between relatedness and the distance between couples, for the cohorts born before 185066. Our analyses within present-day Turko-Mongols reveal more specifically that the structure of the relationship between geographical distance and mating choice inbreeding is not linear, but rather tends to be bell-shaped, and thus cannot be correctly assessed with a single correlation test. Indeed, descendants from parents born 4 to 40 km apart are more inbred than descendants from endogamous couples (≤4 km) or from long-range exogamous ones (>40 km). As a consequence, close inbreeding exists despite geographical exogamy, and about a third of descendants from exogamous couples are inbred.
These results, in addition to those obtained by [Kaplanis et al. 2018]66, highlight the importance of using geographic distances rather than exogamy rates to characterize the impact of exogamy on inbreeding, as already described when studying patrilocality67. Indeed, when we compare mating choice inbreeding patterns for descendants from exogamous and endogamous couples defined for thresholds of 4, 10, 20 and 30 km, we find no significant differences (for number and total length of class C-ROHs and F-Median coefficient: MWU test p-values > 0.1). We only detect significantly lower values in descendants from exogamous couples for larger distances above 40 and 50 km (p-values < 0.03).
Our results also challenge the intuition that exogamy necessarily increases the genetic diversity within a population and therefore reduces drift inbreeding. Indeed, we found that Turko-Mongol populations have a lower genetic diversity (as measured by the mean haplotypic heterozygosity) and more intermediate ROHs associated with drift inbreeding than those of Indo-Iranians despite higher exogamous rates. (…)
Overall, this research sheds light on mating choice preferences: we showed that two thirds of partners that have not dispersed did mate with unrelated individuals, and that drift and mating choice inbreeding is variable, even among close-by populations. We also provide new insights into the relationship between dispersal and inbreeding in humans, based on genetic data, and demonstrate that geographical exogamy is not necessarily negatively associated with mating choice inbreeding, but rather can have a more complex non-linear relationship. Contrary to the common situation in many animals, this finding suggests that Inner Asian human populations who practise exogamy at small geographical scales might be focused on alliance strategies that result in kinship endogamy. (…)
We genotyped 738 individuals belonging to 49 populations from Nepal, Bhutan, North India or Tibet at over 500,000 SNPs, and analysed the genotypes in the context of available worldwide population data in order to investigate the demographic history of the region and the genetic adaptations to the harsh environment. The Himalayan populations resembled other South and East Asians, but in addition displayed their own specific ancestral component and showed strong population structure and genetic drift. We also found evidence for multiple admixture events involving Himalayan populations and South/East Asians between 200 and 2,000 years ago. In comparisons with available ancient genomes, the Himalayans, like other East and South Asian populations, showed similar genetic affinity to Eurasian hunter-gatherers (a 24,000-year-old Upper Palaeolithic Siberian), and the related Bronze Age Yamnaya. The high-altitude Himalayan populations all shared a specific ancestral component, suggesting that genetic adaptation to life at high altitude originated only once in this region and subsequently spread. Combining four approaches to identifying specific positively-selected loci, we confirmed that the strongest signals of high-altitude adaptation were located near the Endothelial PAS domain-containing protein 1 (EPAS1) and Egl-9 Family Hypoxia Inducible Factor 1 (EGLN1) loci, and discovered eight additional robust signals of high-altitude adaptation, five of which have strong biological functional links to such adaptation. In conclusion, the demographic history of Himalayan populations is complex, with strong local differentiation, reflecting both genetic and cultural factors; these populations also display evidence of multiple genetic adaptations to high-altitude environments.
Genetic affinity to ancestral populations
We explored the genetic affinity between the Himalayan populations and five ancient genomes using f3-outgroup statistics. Himalayans show greater affinity to Eurasian hunter-gatherers (MA-1, a 24,000- year-old Upper Palaeolithic Siberian), and the related Bronze Age Yamnaya, than to European farmers (5,500-4,800 years ago; Fig. 5A) or to European hunter-gatherers (La Braña, 7,000 years ago; Fig. 5B), like other South and East Asian populations. We further explored the affinity of Himalayan populations by comparing them with the 45,000-year-old Upper Palaeolithic hunter-gatherer (Ust’-Ishim) and each of MA-1, La Braña, or Yamnaya. Himalayan individuals cluster together with other East Asian populations and show equal distance from Ust’-Ishim and the other ancient genomes, probably because Ust’-Ishim belongs to a much earlier period of time (supplementary fig. S15). We also explored genetic affinity between modern Himalayan populations and five ancient Himalayans (3,150 1,250 years old) from Nepal. The ancient individuals cluster together with modern Himalayan populations in a worldwide PCA (supplementary fig. S16), and the f3-outgroup statistics show modern high-altitude populations have the closest affinity with these ancient Himalayans, suggesting that these ancient individuals could represent a proxy for the first populations residing in the region (supplementary fig. S17 and supplementary table S4). Finally, we explored the genetic affinity of Himalayan samples with the archaic genomes of Denisovans and Neanderthals (Skoglund and Jakobsson 2011), and found that they show a similar sharing pattern with Denisovans and Neanderthals to the other South and East Asian populations. Individuals belonging to four Nepalese, one Cambodian, and three Chinese populations show the highest Denisovan sharing (after populations from Australia and Papua New Guinea) but these values are not significantly greater than other South and East Asian populations (supplementary figs. S18 and S19).
NOTE. The variance explained in the PCA graphics seems to be too high. This happened recently also with the Damgaard et al. (2018) papers (see here the comment by Iosif Lazaridis).
Similarities and differences between high-altitude Himalayan
The most striking example is provided by the Toto from North India, an isolated tribal group with the lowest genetic diversity of the Himalayan populations examined here, indicated by the smallest long-term Ne (supplementary fig. S5), and a reported census size of 321 in 1951 (Mitra 1951), although their numbers have subsequently increased. Despite this extreme substructure, shared common ancestry among the high-altitude populations (Fig. 2C and Fig. 3) can be detected, and the Nepalese in general are distinguished from the Bhutanese and Tibetans (Fig. 2C) and they also cluster separately (Fig. 3). In a worldwide context, they share an ancestral component with South Asians (supplementary fig. S2). On the other hand, the Tibetans do not show detectable population substructure, probably due to a much more recent split in comparison with the other populations (Fig. 2C and supplementary fig. S6). The genetic similarity between the high-altitude populations, including Tibetans, Sherpa and Bhutanese, is also supported by their clustering together on the phylogenetic tree, the PCA generated from the co-ancestry matrix generated by fineSTRUCTURE (supplementary fig. S10 and S11), the lack of statistical significance for most of the D-statistics tests (Yoruba, Han; high-altitude Himalayan 1, high-altitude Himalayan 2), and the absence of correlation between the increased genetic affinity to lowland East Asians and the spatial location of the Himalayan populations (supplementary figs. S12 and S13). Together, these results suggest the presence of a single ancestral population carrying advantageous variants for high-altitude adaptation that separated from lowland East Asians, and then spread and diverged into different populations across the Himalayan region. (…)
Recent admixture events
Himalayan populations show signatures of recent admixture events, mainly with South and East Asian populations as well as within the Himalayan region itself. Newar and Lhasa show the oldest signature of admixture, dated to between 2,000 and 1,000 years ago. Majhi and Dhimal display signatures of admixture within the last 1,000 years. Chetri and Bodo show the most recent admixture events, between 500 and 200 years ago (Fig. 4, supplementary tables S3). The comparison between the genetic tree and the linguistic association of each Himalayan population highlights the agreement between genetic and linguistic sub-divisions, in particular in the Bhutanese and Tibetan populations. Nepalese populations show more variability, with genetic sub-clusters of populations belonging to different linguistic affiliations (Fig. 3B). Modern high-altitude Himalayans show genetic affinity with ancient genomes from the same region (supplementary fig. S17), providing additional support for the idea of an ancient high-altitude population that spread across the Himalayan region and subsequently diverged into several of the present-day populations. Furthermore, Himalayan populations show a similar pattern of allele sharing with Denisovans as other South-East Asian populations (supplementary fig. S18 and S19). Overall, geographical isolation, genetic drift, admixture with neighbouring populations and linguistic subdivision played important roles in shaping the genetic variability we see in the Himalayan region today.
This post should probably read “Consequences of Narasimhan et al. (2018),” too, since there seems to be enough data and materials published by the Copenhagen group in Nature and Science to make a proper interpretation of the data that will appear in their corrected tables.
The finding of late Khvalynsk/early Yamna migrations, identified with early LPIE migrants almost exclusively of R1b-L23 subclades is probably one of the most interesting findings in the recent papers regarding the Indo-European question.
Although there are still few samples to derive fully-fledged theories, they begin to depict a clearer idea of waves that shaped the expansion of Late Proto-Indo-European migrants in Eurasia during the 4th millennium BC, i.e. well before the expansion of North-West Indo-European, Palaeo-Balkan, and Indo-Iranian languages.
Late Khvalynsk expansions and archaic Late PIE
Like Anatolian, Tocharian has been described as having a more archaic nature than the rest of Late PIE. However, Pre-Tocharian belongs to the Late PIE trunk, clearly distinguishable phonetically and morphologically from Anatolian.
It is especially remarkable that – even though it expanded into Asia – it has more in common with North-West Indo-European, hence its classification (together with NWIE) as part of a Northern group, unrelated to Graeco-Aryan.
The linguistic supplement by Kroonen et al. accepts that peoples from the Afanasevo culture (ca. 3000-2500 BC) are the most likely ancestors of Tocharians.
NOTE. For those equating the Tarim Mummies (of R1a-Z93 lineages) with Tocharians, you have this assertion from the linguistic supplement, which I support:
An intermediate stage has been sought in the oldest so-called Tarim Mummies, which date to ca. 1800 BCE (Mallory and Mair 2000; Wáng 1999). However, also the language(s) spoken by the people(s) who buried the Tarim Mummies remain unknown, and any connection between them and the Afanasievo culture on the one hand or the historical speakers of Tocharian on the other has yet to be demonstrated (cf. also Mallory 2015; Peyrot 2017).
New samples of late Khvalynsk origin
These are are the recent samples that could, with more or less certainty, correspond to migration waves from late Khvalynsk (or early Yamna), from oldest to most recent:
The Namazga III samples from the Late Eneolithic period (in Turkmenistan), dated ca. 3360-3000 BC (one of haplogroup J), potentially showing the first wave of EHG-related steppe ancestry into South Asia. Not related to Indo-Iranian migrations.
NOTE. A proper evaluation with further samples from Narasimhan et al. (2018) is necessary, though, before we can assert a late Khvalynsk origin of this ancestry.
Afanasevo samples, dated ca. 3081-2450 BC, with all samples dated before ca. 2700 BC uniformly of R1b-Z2103 subclades, sharing a common genetic cluster with Yamna, showing together the most likely genomic picture of late Khvalynsk peoples.
NOTE 1. Anthony (2007) put this expansion from Repin ca. 3300-3000 BC, while his most recent review (2015) of his own work put its completion ca. 3000-2800. While the migration into Afanasevo may have lasted some time, the wave of migrants (based on the most recent radiocarbon dates) must be set at least before ca. 3100 BC from Khvalynsk.
NOTE 2. I proposed that we could find R1b-L51 in Afanasevo, presupposing the development of R1b-L51 and R1b-Z2103 lineages with separating clans, and thus with dialectal divisions. While finding this is still possible within Khvalynsk regions, it seems we will have a division of these lineages already ca. 4250-4000 BC, which would require a closer follow-up of the different inner late Khvalynsk groups and their samples. For the moment, we don’t have a clear connection through lineages between North-West Indo-European groups and Tocharian.
Subsequent and similar migration waves are probably to be suggested from the new sample of Karagash, beyond the Urals (attributed to the Yamna culture, hence maintaining cultural contacts after the migration waves), of R1b-Z2103 subclade, ca. 3018-2887 BC, potentially connected then to the event that caused the expansion of Yamna migrants westward into the Carpathians at the same time. Not related to Indo-Iranian migrations.
The isolated Darra-e Kur sample, without cultural adscription, ca. 2655 BC, of R1b-L151 lineage. Not related to Indo-Iranian migrations.
The Hajji Firuz samples: I4243 dated ca. 2326 BC, female, with a clear inflow of steppe ancestry; and I2327 (probably to be dated to the late 3rd millennium BC or after that), of R1b-Z2103 lineage. Not related to Indo-Iranian migrations.
NOTE. A new radiocarbon dating of I2327 is expected, to correct the currently available date of 5900-5000 BC. Since it clusters nearer to Chalcolithic samples from the site than I4243 (from the same archaeological site), it is possible that both are part of similar groups receiving admixture around this period, or maybe I2327 is from a later period, coinciding with the Iron Age sample F38 from Iran (Broushaki et al. 2016), with which it closely clusters. Also, the finding of EHG-related ancestry in Maykop samples dated ca. 3700-3000 BC (maybe with R1b-L23 subclades) offers another potential source of migrants for this Iranian group.
NOTE. Samples from Narasimhan et al. (2018) still need to be published in corrected tables, which may change the actual subclades shown here.
These late Khvalynsk / early Yamna migration waves into Asia are quite early compared to the Indo-Iranian migrations, whose ancestors can only be first identified with Volga-Ural groups of Yamna/Poltavka (ca. 3000-2400 BC), with its fully formed language expanding only with MLBA waves ca. 2300-1200 BC, after mixing with incoming Abashevo migrants.
While the authors apparently forget to reference the previous linguistic theories whereby Tocharian is more archaic than the rest of Late PIE dialects, they refer to the ca. 1,000-year gap between Pre-Tocharian and Proto-Indo-Iranian migrations, and thus their obvious difference:
The fact that Tocharian is so different from the Indo-Iranian languages can only be explained by assuming an extensive period of linguistic separation.
Potential linguistic substrates in the Middle East
A few words about relevant substrate language proposals.
What Gordon Whittaker proposes is a North-West Indo-European-related substratum in Sumerian language and texts ca. 3500 BC, which may explain some non-Sumerian, non-Semitic word forms. It is just one of many theories concerning this substratum.
This is a summary of his findings from his latest writing on the subject (a chapter of a book on Indo-European phonetics, from the series Copenhagen Studies in Indo-European):
In Sumerian and Akkadian vocabulary, the cuneiform writing system, and the names of deities and places in Southern Mesopotamia a body of lexical material has been preserved that strongly suggests influence emanating from a superstrate of Indo-European origin. his Indo-European language, which has been given the name Euphratic, is, at present, attested only indirectly through the filters of Sumerian and Akkadian. The attestations consist of words and names recorded from the mid-4th millennium BC (Late Uruk period) onwards in texts and lexical lists. In addition, basic signs that originally had a recognizable pictorial structure in proto-cuneiform preserve (at least from the early 3rd millennium on) a number of phonetic values with no known motivation in Sumerian lexemes related semantically to the items depicted. This suggests that such values are relics from the original logographic values for the items depicted and, thus, that they were inherited from a language intimately associated with the development of writing in Mesopotamia. Since specialists working on proto-cuneiform, most notably Robert K. Englund of the Cuneiform Digital Library Initiative, see little or no evidence for the presence of Sumerian in the corpus of archaic tablets, the proposed Indo-European language provides a potential solution to this problem. It has been argued that this language, Euphratic, had a profound influence on Sumerian, not unlike that exerted by Sumerian and Akkadian on each other, and that the writing system was the primary vehicle of this influence. he phonological sketch drawn up here is an attempt to chart the salient characteristics of this influence, by comparing reconstructed Indo-European lexemes with similarly patterned ones in Sumerian (and, to a lesser extent, in Akkadian).
His original model, based on phonetic values in basic proto-cuneiform signs, is quite imaginative and a very interesting read, if you have the time. His Academia.edu account hosts most of his papers on the subject.
We could speculate about the potential expansion of this substrate language with the commercial contacts between Uruk and Maykop (as I did), now probably more strongly supported because of the EHG found in Maykop samples.
NOTE. We could also put it in relation with the Anatolian language of Mari, but this would require a new reassessment of its North-West Indo-European nature.
Nevertheless, this theory is far from being mainstream, anywhere. At least today.
NOTE. The proposal remains still hypothetic, because of the flaws in the Indo-European parallels – similar to Koch’s proposal of Indo-European in Tartessian inscriptions. A comprehensive critic approach to the theory is found in Sylvie Vanséveren’s A “new” ancient Indo-European language? On assumed linguistic contacts between Sumerian and Indo-European “Euphratic”, in JIES (2008) 36:3&4.
References to Gutian are popping up related to the Hajji Firuz samples of the mid-3rd millennium.
The hypothesis was put forward by Henning (1978) in purely archaeological terms.
This is the relevant excerpt from the book:
(…) Comparativists have asserted that, in spite of its late appearance, Tokharian is a relatively archaic form of Indo-European.3 This claim implies that the speakers of this group separated from their Indo-European brethren at a comparatively early date. They should accordingly have set out on their migrations rather early, and should have appeared within the Babylonian sphere of influence also rather early. Earlier, at any rate, than the Indo-Iranians, who spoke a highly developed (therefore probably later) form of Indo-European. Moreover, as some of the Indo-Iranians after their division into Iranians and Indo-Aryans4 appeared in Mesopotamia about 1500 B.C., we should expect the Proto-Tokharians about 2000 B.C. or even earlier.
If, armed with these assumptions as our working hypothesis, we look through the pages of history, we find one nation – one nation only – that perfectly fulfills all three conditions, which, therefore, entitles us to recognize it as the “Proto-Tokharians”. Tis name was Guti; the intial is also spelled with q (a voiceless back velar or pharyngeal), but the spelling with g is the original one. The closing -i is part of the name, for the Akkadian case-endings are added to it, nom. Gutium etc. Guti (or Gutium, as some scholars prefer) was valid for the nation, considered as an entity, but also for the territory it occupied.
The text goes on to follow the invasion of Babylonia by the Guti, and further eastward expansions supposedly connected with these, to form the attested Tocharians.
Among the Gutian rulers is one Elulumesh, whose name is evidently Akkadian Elulum slightly “Gutianized” by the Gutian case(?) ending -eš.40 This Gutian ruler Elulum is obviously the same man whom we find participating in the scramble for power after the death of Shar-kali-sharrii; his name appears there in Sumerian form without mimation as Elulu.
The Gutian dynasty, from ca. 22nd c. BC appears as follows:
I don’t think we could derive a potential relation to any specific Indo-European branch from this simple suffix repeated in Gutian rulers, though.
The hypothesis of the Tocharian-like nature of the Guti (apart from the obvious error of considering them as the ancestors of Tocharians) remains not contrasted in new works since. It was cited e.g. by Gamkrelidze and Ivanov (1995) to advance their Armenian homeland, and by Mallory and Adams in their Encyclopedia (1997).
It lies therefore in the obscurity of undeveloped archaeological-linguistic hypotheses, and its connection with the attested R1b-Z2103 samples from Iran is not (yet) warranted.
Our findings fit well with current insights from the historical linguistics of this region (Supplementary Information section 2). The steppes were probably largely Iranian-speaking in the first and second millennia bc. This is supported by the split of the Indo-Iranian linguistic branch into Iranian and Indian33, the distribution of the Iranian languages, and the preservation of Old Iranian loanwords in Tocharian34. The wide distribution of the Turkic languages from Northwest China, Mongolia and Siberia in the east to Turkey and Bulgaria in the west implies large-scale migrations out of the homeland in Mongolia since about 2,000 years ago35. The diversification within the Turkic languages suggests that several waves of migration occurred36 and, on the basis of the effect of local languages, gradual assimilation to local populations had previously been assumed37. The East Asian migration starting with the Xiongnu accords well with the hypothesis that early Turkic was the major language of Xiongnu groups38. Further migrations of East Asians westwards find a good linguistic correlate in the influence of Mongolian on Turkic and Iranian in the last millennium39. As such, the genomic history of the Eurasian steppes is the story of a gradual transition from Bronze Age pastoralists of West Eurasian ancestry towards mounted warriors of increased East Asian ancestry—a process that continued well into historical times.
This paper will need a careful reading – better in combination with Narasimhan et al. (2018), when their tables are corrected – , to assess the actual ‘Iranian’ nature of the peoples studied. Their wide and long-term dominion over the steppe could also potentially explain some early samples from Hajji Firuz with steppe ancestry.
For the moment, at first sight, it seems that, in terms of Y-DNA lineages:
R1b-Z93 (especially Z2124 subclades) dominate the steppes in the studied periods.
R1b-P312 is found in Hallstatt ca. 810 BC, which is compatible with its role in the Celtic expansion.
R1b-U106 is found in a West Germanic chieftain in Poprad (Slovakia) ca. 400 AD, during the Migration Period, hence supporting once again the expansion of Germanic tribes especially with R1b-U106 lineages.
A sample of haplogroup R1a-Z282 (Z92) dated ca. 1300 AD in the Golden Horde is probably not quite revealing, not even for the East Slavic expansion.
Also, interestingly, some R1b(xM269) lineages seem to be associated with Turkic expansions from the eastern steppe dated around 500 AD, which probably points to a wide Eurasian distribution of early R1b subclades in the Mesolithic.
NOTE. I have referenced not just the reported subclades from the paper, but also (and mainly) further Y-SNP calls studied by Open Genomes. See the spreadsheet here.
Interesting also to read in the supplementary materials the following, by Michaël Peyrot (emphasis mine):
1. Early Indo-Europeans on the steppe: Tocharians and Indo-Iranians
The Indo-European language family is spread over Eurasia and comprises such branches and languages as Greek, Latin, Germanic, Celtic, Sanskrit etc. The branches relevant for the Eurasian steppe are Indo-Aryan (= Indian) and Iranian, which together form the Indo-Iranian branch, and the extinct Tocharian branch. All Indo-European languages derive from a postulated protolanguage termed Proto-Indo-European. This language must have been spoken ca 4500–3500 BCE in the steppe of Eastern Europe21. The Tocharian languages were spoken in the Tarim Basin in present-day Northwest China, as shown by manuscripts from ca 500–1000 CE. The Indo-Aryan branch consists of Sanskrit and several languages of the Indian subcontinent, including Hindi. The Iranian branch is spread today from Kurdish in the west, through a.o. Persian and Pashto, to minority languages in western China, but was in the 2nd and 1st millennia BCE widespread also on the Eurasian steppe. Since despite their location Tocharian and Indo-Iranian show no closer relationship within Indo-European, the early Tocharians may have moved east before the Indo-Iranians. They are probably to be identified with the Afanasievo Culture of South Siberia (ca 2900 – 2500 BCE) and have possibly entered the Tarim Basin ca 2000 BCE103.
The Indo-Iranian branch is an extension of the Indo-European Yamnaya Culture (ca 3000–2400 BCE) towards the east. The rise of the Indo-Iranian language, of which no direct records exist, must be connected with the Abashevo / Sintashta Culture (ca 2100 – 1800 BCE) in the southern Urals and the subsequent rise and spread of Andronovo-related Culture (1700 – 1500 BCE). The most important linguistic evidence of the Indo-Iranian phase is formed by borrowings into Finno-Ugric languages104–106. Kuz’mina (2001) identifies the Finno-Ugrians with the Andronoid cultures in the pre-taiga zone east of the Urals107. Since some of the oldest words borrowed into Finno-Ugric are only found in Indo-Aryan, Indo-Aryan and Iranian apparently had already begun to diverge by the time of these contacts, and when both groups moved east, the Iranians followed the Indo-Aryans108. Being pushed by the expanding Iranians, the Indo-Aryans then moved south, one group surfacing in equestrian terminology of the Anatolian Mitanni kingdom, and the main group entering the Indian subcontinent from the northwest.
2. Andronovo Culture: Early Steppe Iranian
Initially, the Andronovo Culture may have encompassed speakers of Iranian as well as Indo-Aryan, but its large expansion over the Eurasian steppe is most probably to be interpreted as the spread of Iranians. Unfortunately, there is no direct linguistic evidence to prove to what extent the steppe was indeed Iranian speaking in the 2nd millennium BCE. An important piece of indirect evidence is formed by an archaic stratum of Iranian loanwords in Tocharian34,109. Since Tocharian was spoken beyond the eastern end of the steppe, this suggests that speakers of Iranian spread at least that far. In the west of the Tarim Basin the Iranian languages Khotanese and Tumshuqese were spoken. However, the Tocharian B word etswe ‘mule’, borrowed from Iranian *atswa- ‘horse’, cannot derive from these languages, since Khotanese has aśśa- ‘horse’ with śś instead of tsw. The archaic Iranian stratum in Tocharian is therefore rather to be connected with the presence of Andronovo people to the north and possibly to the east of the Tarim Basin from the middle of the 2nd millennium BCE onwards110.
Since Kristiansen and Allentoft sign the paper (and Peyrot is a colleague of Kroonen), it seems that they needed to expressly respond to the growing criticism about their recent Indo-European – Corded Ware Theory. That’s nice.
IECWT-proponents are apparently not prepared to let it go quietly, and instead of challenging the traditional Neolithic Uralic homeland in Eastern Europe with a recent paper on the subject, they selected an older one which partially fit, from Kuz’mina (2001), now shifting the Uralic homeland to the east of the Urals (when Kuz’mina asserts it was south of the Urals).
Different authors comment later in this same paper about East Uralic languages spreading quite late, so even their text is not consistent among collaborating authors.
Also interesting is the need to resort to the questionable argument of early Indo-Aryan loans – which may have evidently been Indo-Iranian instead, since there is no way to prove a difference between both stages in early Uralic borrowings from ca. 4,500-3,500 years ago…
NOTE. I don’t mind repeating it again: Uralic is one possibility (the most likely one) for the substrate language that Corded Ware migrants spread, but it could have been e.g. another Middle PIE dialect, similar to Proto-Anatolian (after the expansion of Suvorovo-Novodanilovka chiefs). I expressly stated this in the Corded Ware substrate hypothesis, since the first edition. What was clear since 2015, and should be clear to anyone now, is that Corded Ware did not spread Late PIE languages to Europe, and that some east CWC groups only spread languages to Asia after admixing with East Yamna. If they did not spread Uralic, then it was a language or group of languages phonetically similar, which has not survived to this day.
At least we won’t have the Yamna -> Corded Ware -> BBC nonsense anymore, and they expressly stated that LPIE is to be associated with Yamna, and in particular the “Indo-Iranian branch is an extension of the Indo-European Yamnaya Culture (ca 3000–2400 BCE) to the East” (which will evidently show an East Yamna / Poltavka society of R1b-L23 subclades), so that earlier Eneolithic cultures have to be excluded, and Balto-Slavic identification with East Europe is also out of the way.
Niraj Rai, head of the DNA Laboratory where the samples from the Harappan site of Rakhigarhi in Haryana are being analysed, has this to say:
It will show that there is no steppe contribution to the Indus Valley DNA.
The Indus Valley people were indigenous, but in the sense that their DNA had contributions from near eastern Iranian farmers mixed with the Indian hunter-gatherer DNA, that is still reflected in the DNA of the people of the Andaman islands.
The Rakhigarhi study provides direct evidence for the claims of a paper published in preprint on bioRxiv in March 2018, which outlines a comprehensive model for the settlement of different populations within the subcontinent.
Rai had earlier told Open magazine that the male:
Y chromosome R1a genetic marker is missing in the Rakhigarhi sample.
Commenting on other hypotheses:
any model of migration of Indo-Europeans from South Asia simply cannot fit the data that is now available.
The paper based on the examination of the Rakhigarhi samples will soon be published on bioRxiv.
The genetic formation of Central and South Asian populations has been unclear because of an absence of ancient DNA. To address this gap, we generated genome-wide data from 362 ancient individuals, including the first from eastern Iran, Turan (Uzbekistan, Turkmenistan, and Tajikistan), Bronze Age Kazakhstan, and South Asia. Our data reveal a complex set of genetic sources that ultimately combined to form the ancestry of South Asians today. We document a southward spread of genetic ancestry from the Eurasian Steppe, correlating with the archaeologically known expansion of pastoralist sites from the Steppe to Turan in the Middle Bronze Age (2300-1500 BCE). These Steppe communities mixed genetically with peoples of the Bactria Margiana Archaeological Complex (BMAC) whom they encountered in Turan (primarily descendants of earlier agriculturalists of Iran), but there is no evidence that the main BMAC population contributed genetically to later South Asians. Instead, Steppe communities integrated farther south throughout the 2nd millennium BCE, and we show that they mixed with a more southern population that we document at multiple sites as outlier individuals exhibiting a distinctive mixture of ancestry related to Iranian agriculturalists and South Asian hunter-gathers. We call this group Indus Periphery because they were found at sites in cultural contact with the Indus Valley Civilization (IVC) and along its northern fringe, and also because they were genetically similar to post-IVC groups in the Swat Valley of Pakistan. By co-analyzing ancient DNA and genomic data from diverse present-day South Asians, we show that Indus Periphery-related people are the single most important source of ancestry in South Asia — consistent with the idea that the Indus Periphery individuals are providing us with the first direct look at the ancestry of peoples of the IVC — and we develop a model for the formation of present-day South Asians in terms of the temporally and geographically proximate sources of Indus Periphery-related, Steppe, and local South Asian hunter-gatherer-related ancestry. Our results show how ancestry from the Steppe genetically linked Europe and South Asia in the Bronze Age, and identifies the populations that almost certainly were responsible for spreading Indo-European languages across much of Eurasia.
NOTE. The supplementary material seems to be full of errors right now, because it lists as R1b-M269 (and further subclades) samples that have been previously expressly said were xM269, so we will have to wait to see if there are big surprises here. So, for example, samples from Mal’ta (M269), Iron Gates (M269 and L51), and Latvia Mesolithic (L51), a Deriivka sample from 5230 BC (M269), Armenia_EBA (Z2103)…Also, the sample from Yuzhnyy Oleni Ostrov is R1a-M417 now.
EDIT (1 APR 2018): The main author has confirmed on Twitter that they have used a new Y Chr caller that calls haplogroups given the data provided, and depending on the coverage tried to provide a call to the lowest branch of the tree possible, so there are obviously a lot of mistakes – not just in the subclades of R. A revision of the paper is on its way, and soon more people will be able to work with the actual samples, since they say they are releasing them.
Nevertheless, since it is subclades (and not haplogroups) the apparent source of gross errors, for the moment it seems we can say with a great degree of confidence that:
New samples of East Yamna / Poltavka are of haplogroup R1b-L23.
Afanasevo is confirmed to be dominated by R1b-M269.
With lesser confidence in precise subclades, we find that:
A sample from Hajji Firuz in Iran ca. 5650 BC, of subclade R1b-Z2103, may confirm Mesolithic R1b-M269 lineages from the Caucasus as the source of CHG ancestry to Khvalynsk/Yamna, and be thus the reason why Reich wrote about a potential PIE homeland south of the Caucasus. (EDIT 11 APR 2018) The sample shows steppe ancestry, therefore the date is most likely incorrect, and a new radiocarbon dating is due. It is still interesting – depending on the precise subclade – for its potential relationship with IE migrations into the area.
New samples of East Yamna / Poltavka are of haplogroup R1b-Z2103.
Afanasevo migrants are mainly of haplogroup R1b-Z2103.
The Darra-e Kur sample, ca. 2655, of haplogroup R1b-L151, without a clear cultural adscription, may be the expected sign of Afanasevo migrants (Pre-Proto-Tocharian speakers) expanding a Northern Indo-European (in contrast with a Southern or Graeco-Aryan) dialect, in a region closely linked with the later desert mummies in the Tarim Basin. Its early presence there would speak in favour of a migration through the Inner Asian Mountain Corridor previous to the one caused by Andronovo migrants.
Sintashta shows a mixed R1b-Z2103 / R1a-Z93 society.
Later Indo-Iranian migrations are apparently dominated by R1a-Z2123, an early subclade of R1a-Z93, also found in Srubna.
R1b is also seen later in BMAC (ca. 1487 BC), although its subclade is not given.
There is also a sample of R1a-Z283 subclade in the eastern steppe (ca. 1600 BC). What may be interesting about it is that it could mark one of the subclades not responsible for the expansion of Balto-Slavic (or responsible for it with the expansion of Srubna, for those who support an Indo-Slavonic branch related Sintashta-Potapovka).
A sample of R1b-U106 subclade is found in Loebanr_IA ca. 950 BC, which – together with the sample of Darra-e Kur – is compatible with the presence of L51 in Yamna.
NOTE. Errors in haplogroups of previously published samples make every subclade of new samples from the supplementary table questionable, but all new samples (safe for the Darra_i_Kur one) were analysed and probably reported by the Reich Lab, and at least upper subclades in each haplogroup tree seem mostly coherent with what was expected. Also, the contribution of Iranian Farmer related (a population in turn contributing to Hajji Firuz) to Khvalynsk in their sketch of the genetic history may be a sign of the association of R1b-M269 lineages with CHG ancestry, although previous data on precise R1b subclades in the region contradict this. (EDIT 11 APR 2018) The sample of Hajji Firuz is most likely much younger than the published date, hence its younger subclade may be correct. No revision or comment on this matter has been published, though.
Also, it seems that the Corded Ware culture appears now irrelevant for Late Proto-Indo-European migrations. Observe:
Our results also shed light on the question of the origins of the subset of Indo-European languages spoken in India and Europe (45). It is striking that the great majority of Indo-European speakers today living in both Europe and South Asia harbor large fractions of ancestry related to Yamnaya Steppe pastoralists (corresponding genetically to the Steppe_EMBA cluster), suggesting that “Late Proto-Indo-European”—the language ancestral to all modern Indo- European languages—was the language of the Yamnaya (46). While ancient DNA studies have documented westward movements of peoples from the Steppe that plausibly spread this ancestry to Europe (5, 31), there has not been ancient DNA evidence of the chain 488 of transmission to South Asia. Our documentation of a large-scale genetic pressure from Steppe_MLBA groups in the 2nd millennium BCE provides a prime candidate, a finding that is consistent with archaeological evidence of connections between material culture in the Kazakh middle-to-late Bronze Age Steppe and early Vedic culture in India (46).
NOTE. If they correct the haplogroups soon, I will update the information in this post. Unless there is a big surprise that merits a new one, of course.
EDIT (1 APR 2018): Multiple minor edits to the original post.
EDIT (2 APR 2018): While I and other simple-minded people were only looking to confirm our previous theories using Y-DNA haplogroups, and are content with wildly speculating over the consequences if some of those strange (probably wrong) ones were true, intelligent people are using their time for something useful, interpreting the results of the investigation as described in the paper, to offer a clearer picture of Indo-Iranian migrations for everyone:
Featured image, from the article: “A Tale of Two Subcontinents. The prehistory of South Asia and Europe are parallel in both being impacted by two successive spreads, the first from the Near East after 7000 BCE bringing agriculturalists who mixed with local hunter-gatherers, and the second from the Steppe after 3000 BCE bringing people who spoke Indo-European languages and who mixed with those they encountered during their migratory movement. Mixtures of these mixed populations then produced the rough clines of ancestry present in both South Asia and in Europe today (albeit with more variable proportions of local hunter-gatherer-related ancestry in Europe than in India), which are (imperfectly) correlated to geography. The plot shows in contour lines the time of the expansion of Near Eastern agriculture. Human movements and mixtures, which also plausibly contributed to the spread of languages, are shown with arrows.”
Nevertheless, since we have very few samples, I think we could still see a clear genetic contribution from Yamna to Corded Ware immigrants in the North Caspian region (from Abashevo, in turn a mix of Fatyanovo/Balanovo and Catacomb/Poltavka cultures) in terms of:
Ancestral components and PCA in new Sintashta-Petrovka, Andronovo, and/or later samples – similar the ‘steppe’ drift seen in Potapovka relative to Sintashta samples, both formed by incoming Corded Ware migrants – ; and
R1b-L23 subclades, either appearing scattered during the Sintashta melting pot (of Abashevo/R1a-Z645 and East Yamna-Poltavka/R1b-Z2103 peoples), or resurging after this period, as we have seen in Pre-Balto-Slavic territory.
A lot of people seem to be looking like crazy since O&M 2018 for some sort of connection between Corded Ware and Yamna migrants in Eastern and Central Europe (wheter in SNP calls of samples published, or among almost forgotten academic papers), either to support the ideas of the 2015 papers – for those who relied on their conclusions and built (even if only mentally) far-fetched migration models around it – , or just because of some sort of absurd continuity theory involving modern R1a-Z645 subclades:
Some (the nostalgic ones?) keep looking for just one sample of R1a-Z645 in Yamna, for the same reason.
NOTE. The situation we have seen with the hundreds of samples from O&M 2018, and with the recent additional Eastern European samples, depict an unexpected absolutely clear-cut distinction in Y-DNA haplogroups between Corded Ware and Yamna/Bell Beaker: I really can’t see how the situation could be more obvious for everyone, so I doubt any further samples will make certain people change their minds. Their hope is, I guess, that just one sample may give some more oxygen to infinite pet theories, as we are still surprisingly seeing even with reactionary R1b autochthonous continuists in Western Europe…
However, looking into the most likely future for the field, what we should be expecting right now is continuity of Yamna ancestry and lineages in early Proto-Indo-Iranian territory. Since we only have a few samples from Sintashta-Petrovka, Potapovka, and Andronovo, I think there might be a sizeable number of R1b-Z2103 subclades in the territory inhabited by those who – no doubt – spread the language into Central Asia.
in the Balkans (e.g. in Vučedol or Makó-Kosihy-Čaka), including Greek and even in historical Armenian territory (potentially including Iran Iron Age sample F38 and Armenia LBA/IA RISE397, although the Mitanni may be a confounding factor here), showing the expansion of Palaeo-Balkan languages;
If we find now, as I expect, genetic continuity of east Yamna in Sintashta -> Andronovo (relative to other late Corded Ware peoples), probably including haplogroup R1b-Z2103 mixed with R1a-Z93 before its further reduction of subclades (e.g. to L657) and expansion during its subsequent spread southward…
Why exactly do we need Corded Ware to explain migrations of Late Indo-European speakers?
In other words: if we had the data we have today in 2015, would we have a need for Corded Ware to explain Indo-European migrations from the steppe? Are some people so blinded by their will to (appear to) be right in their past interpretations that they can’t just let go?
NOTE. On a side note, wouldn’t it be nice for this paper to publish some other R1b-L23 (x2103) sample – maybe even R1b-L51 – in Yamna, Andronovo, or Afanasevo territory, to end both autochthonous continuity theories (of North-Eastern and Western Europe) at the same time?
I really hope someone in David Reich’s team understands this matter, or else they will still identify Corded Ware as the (now probably ‘a’ instead) vector of expansion of Indo-European languages, and some of us will still have fun for another 2 or 3 years with such conclusions, until someone in the lab realizes that ancestry ≠ population ≠ ethnic identification ≠ language.
NOTE. It seems rather dull to read how people are discussing in the Twitterverse conventional constructs like ‘human race‘ as found in Reich’s op-ed in The New York Times, as if such grandiose semantic discussions had any practical meaning, when basic anthropological questions actually relevant for Genomics, like the essential ancestral component ≠ people tenet seem not to be of interest for anyone in the field….
Since our Indo-European demic difusion model (and its consequences for our reconstruction of North-West Indo-European) and this blog are becoming more and more popular each day – judging by the constant growth in visits in the past 6 months or so – , I guess the simplemindedness and predictability of certain geneticists is benefitting traditional anthropology directly, driving more and more amateur geneticists to look for sound academic models to answer the growing inconsistencies of genetic research.
NOTE. I am not saying the rejection of Corded Ware as spreading Indo-European is definitive. Maybe more samples within some years will depict a clear ancient expansion of Early or Middle Proto-Indo-Europeans from Khvalynsk to the forest-steppe and forest zone, and later with certain Corded Ware migrants into Central Europe, over whose territory a Late Indo-European dialect from Bell Beakers became the superstrate, as some have proposed in the past – e.g. to explain Krahe’s Old European hydronymy. I really doubt you could demonstrate such an old ethnolinguistic identification with a clear, unbroken archaeological trail, though, and we know now that this old hydronymy is probably of Late Indo-European nature (possibly even more recent).
What I am saying is: with the data we have now, it does not make any sense to keep the anthropological models invented by geneticists ex nihiloin 2015, and the hundred different alternative Late Indo-European migration models that are – born – with – each – new – paper.
These Yamna -> Corded Ware migration models didn’t have any sense for me since early 2016, but now after O&M 2017, and especially O&M 2018, I don’t think any geneticist with a little knowledge in Linguistics or Archaeology (if they are decent about their quest for truth in describing ancient European migrations) would buy them, if not for some sort of created ‘tradition’. So let’s ditch Corded Ware as Late Indo-European-speaking, let’s accept that late Corded Ware migrants should most likely be identified as early Uralic speakers, and then future data will tell if we are – again – wrong.
Please, don’t let Genomics become another pseudoscience based solely on Bioinformatics like glottochronology: let anthropologists (preferably mainstream archaeologists, but also the true Indo-Europeanists, linguists) help you interpret your raw data. Don’t deceive yourselves thinking that you have read enough about the Indo-European question, or that you know enough Indo-Europeanists (say what?) to derive your own conclusions.
Use the South Asia paper to begin expressly retracting the Corded Ware mess.
It happens so that the discussion has turned lately mainly to ancient Y-DNA haplogroups, because they help confirm previous mainstream anthropological models of cultural diffusion and migration. It is obviously not reasonable to judge prehistoric ethnolinguistic migrations from ca. 5,000 years ago based on historical nation-states and ethnic or religious concepts invented since the Middle Ages, coupled with “your” people’s main modern (or your own) paternal lineage.
EDIT (27 MAR 2018): Minor corrections and post made shorter.
An insufficient number of archaeological surveys has been carried out to date on Harappan Civilization cemeteries. One case in point is the necropolis at Rakhigarhi site (Haryana, India), one of the largest cities of the Harappan Civilization, where most burials within the cemetery remained uninvestigated. Over the course of the past three seasons (2013 to 2016), we therefore conducted excavations in an attempt to remedy this data shortfall. In brief, we found different kinds of graves co-existing within the Rakhigarhi cemetery in varying proportions. Primary interment was most common, followed by the use of secondary, symbolic, and unused (empty) graves. Within the first category, the atypical burials appear to have been elaborately prepared. Prone-positioned internments also attracted our attention. Since those individuals are not likely to have been social deviants, it is necessary to reconsider our pre-conceptions about such prone-position burials in archaeology, at least in the context of the Harappan Civilization. The data presented in this report, albeit insufficient to provide a complete understanding of Harappan Civilization cemeteries, nevertheless does present new and significant information on the mortuary practices and anthropological features at that time. Indeed, the range of different kinds of burials at the Rakhigarhi cemetery do appear indicative of the differences in mortuary rituals seen within Harappan societies, therefore providing a vivid glimpse of how these people respected their dead.