Yamnaya replaced Europeans, but admixed heavily as they spread to Asia

narasimhan-spread-yamnaya-ancestry

Recent papers The formation of human populations in South and Central Asia, by Narasimhan, Patterson et al. Science (2019) and An Ancient Harappan Genome Lacks Ancestry from Steppe Pastoralists or Iranian Farmers, by Shinde et al. Cell (2019).

NOTE. For direct access to Narasimhan, Patterson et al. (2019), visit this link courtesy of the first author and the Reich Lab.

I am currently not on holidays anymore, and the information in the paper is huge, with many complex issues raised by the new samples and analyses rather than solved, so I will stick to the Indo-European question, especially to some details that have changed since the publication of the preprint. For a summary of its previous findings, see the book series A Song of Sheep and Horses, in particular the sections from A Clash of Chiefs where I discuss languages and regions related to Central and South Asia.

I have updated the maps of the Preshistory Atlas, and included the most recently reported mtDNA and Y-DNA subclades. I will try to update the Eurasian PCA and related graphics, too.

NOTE. Many subclades from this paper have been reported by Kolgeh (download), Pribislav and Principe at Anthrogenica on this thread. I have checked some out for comparison, but even if it contradicted their analyses mine would be the wrong ones. I will upload my spreadsheets and link to them from this page whenever I find the time.

caucasus-cline-narasimhan
Ancestry clines (1) before and (2) after the advent of farming. Colour modified from the original to emphasize the CHG cline: notice the apparent relevance of forest-steppe groups in the formation of this CHG mating network from which Pre-Yamnaya peoples emerged.

Indo-Europeans

I think the Narasimhan, Patterson et al. (2019) paper is well-balanced, and unexpectedly centered – as it should – on the spread of Yamnaya-related ancestry (now Western_Steppe_EMBA) as the marker of Proto-Indo-European migrations, which stretched ca. 3000 BC “from Hungary in the west to the Altai mountains in the east”, spreading later Indo-European dialects after admixing with local groups, from the Atlantic to South Asia.

I. Afanasievo

I.1. East or West PIE?

I expected Afanasievo to show (1) R1b-L23(xZ2103, xL51) and (2) R1b-L51 lineages, apart from (3) the known R1b-Z2103 ones, pointing thus to an ancestral PIE community before the typical Yamnaya bottlenecks, and with R1b-L51 supporting a connection with North-West Indo-European. The presence of some samples of hg. Q pointed in this direction, too.

However, Afanasievo samples show overwhelmingly R1b-Z2103 subclades (all except for those with low coverage), all apparently under R1b-Z2108 (formed ca. 3500 BC, TMRCA ca. 3500 BC), like most samples from East Yamnaya.

This necessarily shifts the split and spread of R1b-L23 lineages to Khvalynsk/early Repin-related expansions, in line with what TMRCA suggested, and what advances by Anthony (2019) and Khokhlov (2018) on future samples from the Reich Lab suggest.

Given the almost indistinguishable ancestry between Afanasievo and Early Yamnaya, there seems to be as of yet little potential information to support in population genomics that Pre-Tocharians were more closely related to North-West Indo-Europeans than to Graeco-Aryans, as it is proposed in linguistics based on the few shared traits between them, and the lack of innovations proper of the Graeco-Aryan community.

NOTE. A new issue of Wekʷos contains an abstract from a relevant paper by Blažek on vocabulary for ‘word’, including the common NWIE *wrdʰo-/wordʰo-, but also a new (for me, at least) Northern Indo-European one: *rēki-/*rēkoi̯-, shared by Slavic and Tocharian.

The fact that bottlenecks happened around the time of the late Repin expansion suggests that we might be able to see different clans based on the predominant lineages developing around the Don-Volga area in the 4th millennium BC. The finding of Pre-R1b-L51 in Lopatino (see below), and of a Catacomb sample of hg. R1b-Z2103(Z2105-) in the North Caucasus steppe near Novoaleksandrovskij also support a star-like phylogeny of R1b-L23 stemming from the Don-Volga area.

NOTE. Interestingly, a dismissal of a common trunk between Tocharian and North-West Indo-European would mean that shared similarities between such disparate groups could be traced back to a Common Late PIE trunk, and not to a shared (western) Repin community. For an example of such a ‘pure’ East-West dialectal division, see the diagram of Adams & Mallory (2007) at the end of the post. It would thus mean a fatal blow to Kortlandt’s Indo-Slavonic group among other hypothetical groupings (remade versions of the ancient Centum-Satem division), as well as to certain assumptions about laryngeal survival or tritectalism that usually accompany them. Still, I don’t think this is the case, so the question will remain a linguistic one, and maybe some similarities will be found with enough number of samples that differentiate Northern Indo-Europeans from the East Yamna/Catacomb-Poltavka-Balkan_EBA group.

afanasievo-y-dna
Y-chromosome haplogroups of Afanasievo samples and neighbouring groups. See full maps.

I.2. Expansion or resurgence of hg. Q1b?

Haplogroup Q1b-Y6802(xY6798) seems to be the main lineage that expanded with Afanasievo, or resurged in their territory. It’s difficult to tell, because the three available samples are family, and belong to a later period.

NOTE. I have finally put some order to the chaos of Q1a vs. Q1b subclades in my spreadsheet and in the maps. The change of ISOGG 2016 to 2017 has caused that many samples reported as of Q1 subclades from papers prepared during the 2017-2018 period, and which did not provide specific SNP calls, were impossible to define with certainty. By checking some of them I could determine the specific standard used.

In favour of the presence of this haplogroup in the Pre-Yamnaya community are:

  • The statement by Anthony (2019) that Q1a [hence maybe Q1b in the new ISOGG nomenclature] represented a significant minority among an R1b-rich community.
  • The sample found in a Sintastha WSHG outlier (see below), of hg. Q1b-Y6798, and the sample from Lola, of hg. Q1b-L717, are thus from other lineage(s) separated thousands of years from the Afanasievo subclade, but might be related to the Khvalynsk expansion, like R1b-V1636 and R1b-M269 are.

These are the data that suggest multiple resurgence events in Afanasievo, rather than expanding Q1b lineages with late Repin:

  • Overwhelming presence of R1b in early Yamnaya and Afanasievo samples; one Q1(xQ1b) sample reported in Khvalynsk.
  • The three Q1b samples appear only later, although wide CI for radiocarbon dates, different sites, and indistinguishable ancestry may preclude a proper interpretation of the only available family.
    • Nevertheless, ancestry seems unimportant in the case of Afanasievo, since the same ancestry is found up to the Iron Age in a community of varied haplogroups.
  • Another sample of hg. Q1b-Y6802(xY6798) is found in Aigyrzhal_BA (ca. 2120 BC), with Central_Steppe_EMBA (WSHG-related) ancestry; however, this clade formed and expanded ca. 14000 BC.
  • The whole Altai – Baikal area seems to be a Q1b-L54 hotspot, although admittedly many subclades separated very early from each other, so they might be found throughout North Eurasia during the Neolithic.
  • One Afanasievo sample is reported as of hg. C in Shin (2017), and the same haplogroup is reported by Hollard (2014) for the only available sample of early Chemurchek to date, from Kulala ula, North Altai (ca. 2400 BC).
afanasievo-chemurchek-y-dna
Y-chromosome haplogroups of late Afanasievo – early Chemurchek samples and neighbouring groups. See full maps.

I.3. Agricultural substrate

Evidence of continuous contacts of Central_Steppe_MLBA populations with BMAC from ca. 2100 BC on – visible in the appearance of Steppe ancestry among BMAC samples and BMAC ancestry among Steppe pastoralists – supports the close interaction between Indo-Iranian pastoralists and BMAC agriculturalists as the origin of the Asian agricultural substrate found in Proto-Indo-Iranian, hence likely related to the language of the Oxus Civilization.

Similar to the European agricultural substrate adopted by West Yamnaya settlers (both NWIE and Palaeo-Balkan speakers), Tocharian shows a few substrate terms in common with Indo-Iranian, which can be explained by contacts in different dialectal stages through phonetic reconstruction alone.

The recent Hermes et al. (2019) supports the early integration of pastoralism and millet cultivation in Central Asia (ca. 2700 BC or earlier), with the spread of agriculture to the north – through the Inner Asian Mountain Corridor – being thus unrelated to the Indo-Iranian expansions, which might support independent loans.

However, compared to the huge number of parallel shared loans between NWIE and Palaeo-Balkan languages in the European substratum, Indo-Iranians seem to have been the first borrowers of vocabulary from Asian agriculturalists, while Proto-Tocharian shows just one certain related word, with phonetic similarities that warrant an adoption from late Indo-Iranian dialects.

chemurchek-sintashta-bmac
Y-chromosome haplogroups of Sintashta, Central Asia, and neighbouring groups in the Early Bronze Age. See full maps.

The finding of hg. (pre-)R1b-PH155 in a BMAC sample from Dzharkutan (to the west of Xinjiang) together with hg. R1b in a sample from Central Mongolia previously reported by Shin (2017) support the widespread presence of this lineage to the east and west of Xinjiang, which means it might have become incorporated to Indo-Iranian migrants into the Xiaohe horizon, to the Afanasievo-Chemurchek-derived groups, or the later from the former. In other words, the Island Biogeography Theory with its explanation of founder effects might be, after all, applicable to the whole Xinjiang area, not only during the Chemurchek – Tianshan-Beilu – Xiaohe interaction.

Of course, there is no need for too complicated models of haplogroup resurgence events in Central and South Asia, seeing how the total amount of hg. R1a-L657 (today prevalent among Indo-Aryan speakers from South Asia) among ancient Western/Central_Steppe_MLBA-related samples amounts to a total of 0, and that many different lineages survived in the region. Similar cases of haplogroup resurgence and Y-DNA bottleneck events are also found in the Central and Eastern Mediterranean, and in North-Eastern Europe. From the paper:

[It] could reflect stronger ecological or cultural barriers to the spread of people in South Asia than in Europe, allowing the previously established groups more time to adapt and mix with incoming groups. A second difference is the smaller proportion of Steppe pastoralist– related ancestry in South Asia compared with Europe, its later arrival by ~500 to 1000 years, and a lower (albeit still significant) male sex bias in the admixture (…).

Y-chromosome haplogroups of samples from the Srubna-Andronovo and Andronovo-related horizon, Xiaohe, late BMAC, and neighbouring groups. See full maps.

II. R1b-Beakers replaced R1a-CWC peoples

II.1. R1a-M417-rich Corded Ware

Newly reported Corded Ware samples from Radovesice show hg. R1a-M417, at least some of them xZ645, ‘archaic’ lineages shared with the early Bergrheinfeld sample (ca. 2650 BC) and with the coeval Esperstedt family, hence supporting that it eventually became the typical Western Corded Ware lineage(s), probably dominating over the so-called A-horizon and the Single Grave culture in particular. On the other hand, R1a-Z645 was typical of bottlenecks among expanding Eastern Corded Ware groups.

Interestingly, it is supported once again that known bottlenecks under hg. R1a-M417 happened during the Corded Ware expansion, evidenced also by the remarkable high variability of male lineages among early Corded Ware samples. Similarly, these Corded Ware samples from Bohemia form part of the typical ‘Central European’ cluster in the PCA, which excludes once again not only the ‘official’ Espersted outlier I1540, but also the known outlier with Yamnaya ancestry.

NOTE. The fact that Esperstedt is closely related geographically and in terms of ancestry to later Únětice samples further complicates the assumption that Únětice is a mixture of Bell Beakers and Corded Ware, being rather an admixture of incoming Bell Beakers with post-Yamnaya vanguard settlers who admixed with Corded Ware (see more on the expansion of Yamnaya ancestry). In other words, Únětice is rather an admixture of Yamnaya+EEF with Yamnaya+(CWC+EEF).

Y-chromosome haplogroups of samples from Catacomb, Poltavka, Balkan EBA, and Bell Beaker, as well as neighbouring groups. See full maps.

On Ukraine_Eneolithic I6561

If the bottlenecks are as straightforward as they appear, with a star-like phylogeny of R1a-M417 starting with the Pre-Corded Ware expansion, then what is happening with the Alexandria sample, so precisely radiocarbon dated to ca. 4045-3974 BC? The reported hg. R1a-M417 was fully compatible, while R1a-Z645 could be compatible with its date, but the few positive SNPs I got in my analysis point indeed to a potential subclade of R1a-Z94, and I trust more experienced hobbyists in this ‘art’ of ascertaining the SNPs of ancient samples, and they report hg. R1a-Z93 (Z95+, Y26+, Y2-).

Seeing how Y-DNA bottlenecks worked in Yamnaya-Afanasievo and in Corded Ware and related groups, and if this sample really is so deep within R1a-Z93 in a region that should be more strongly affected by the known Neolithic Y-chromosome bottlenecks and forest-steppe ecotone, someone from the lab responsible for this sample should check its date once again, before more people keep chasing their tails with an individual that (based on its derived SNPs’ TMRCA) might actually be dated to the Bronze Age, where it could make much more sense in terms of ancestry and position in the PCA.

EDIT (14 SEP 2019): … and with the fact that he is the first individual to show the genetic adaptation for lactase persistence (I3910-T), which is only found later among Bell Beakers, and much later in Sintashta and related Steppe_MLBA peoples (see comments below).

This is also evidenced by the other Ukraine_Eneolithic (likely a late Yamnaya) sample of hg. R1b-Z2103 from Dereivka (ca. 2800 BC) and who – despite being in a similar territory 1,000 years later – shows a wholly diluted Yamnaya ancestry under typically European HG ancestry, even more so than other late Sredni Stog samples from Dereivka of ca. 3600-3400 BC, suggesting a decrease in Steppe ancestry rather than an increase – which is supposedly what should be expected based on the ancestry from Alexandria…

Like the reported Chalcolithic individual of Hajji Firuz who showed an apparently incompatible subclade and Yamnaya ancestry at least some 1,000 years before it should, and turned out to be from the Iron Age (see below), this may be another case of wrong radiocarbon dating.

NOTE. It would be interesting, if this turns out to be another Hajji Firuz-like error, to check how well different ancestry models worked in whose hands exactly, and if anyone actually pointed out that this sample was derived, and not ancestral, to many different samples that were used in combination with it. It would also be a great control to check if those still supporting a Sredni Stog origin for PIE would shift their preference even more to the north or west, depending on where the first “true” R1a-M417 samples popped up. Such a finding now could be thus a great tool to discover whether haplogroup-based bias plays a role in ancestry magic as related to the Indo-European question, i.e. if it really is about “pure statistics”, or there is something else to it…

II.1. R1b-L51-rich Bell Beakers

The overwhelming majority of R1b-L51 lineages in Radovesice during the Bell Beaker period, just after the sampled Corded Ware individuals from the same site, further strengthen the hypothesis of an almost full replacement of R1a-M417 lineages from Central Europe up to southern Scandinavia after the arrival of Bell Beakers.

Yet another R1b-L151* sample has popped up in Central Europe, in the individual classified as Bilina_BA (ca. 2200-800 BC), which clusters with Bell Beakers from Bohemia, with the outlier from Turlojiškė, and with Early Slavs, suggesting once again that a group of central-east European Beakers represented the Pre-Proto-Balto-Slavic community before their spread and admixture events to the east.

The available ancient distribution of R1b-L51*, R1b-L52* or R1b-L151* is getting thus closer to the most likely origin of R1b-L51 in the expansion of East Bell Beakers, who trace their paternal ancestors to Yamnaya settlers from the Carpathian Basin:

NOTE. Some of these are from other sources, and some are samples I have checked in a hurry, so I may have missed some derived SNPs. If you send me a corrected SNP call to dismiss one of these, or more ‘archaic’ samples, I’ll correct the map accordingly. See also maps of modern distributionof R1b-M269 subclades.

r1b-l51-ancient-europe
Distribution of ‘archaic’ R1b-L51 subclades in ancient samples, overlaid over a map of Yamnaya and Bell Beaker migrations. In blue, Yamnaya Pre-L51 from Lopatino (not shown) and R1b-L52* from BBC Augsburg. In violet, R1b-L51 (xP312,xU106) from BBC Prague and Poland. In maroon, hg. R1b-L151* from BBC Hungary, BA Bohemia, and (not shown) a potential sample from BBC at Mondelange, which is certainly xU106, maybe xP312. Interestingly, the earliest sample of hg. R1b-U106 (a lineage more proper of northern Europe) has been found in a Bell Beaker from Radovesice (ca. 2350 BC), between two of these ‘archaic’ R1b-L51 samples; and a sample possibly of hg. R1b-ZZ11+ (ancestral to DF27 and U152) was found in a Bell Beaker from Quedlinburg, Germany (ca. 2290 BC), to the north-west of Bohemia. The oldest R1b-U152 are logically from Central Europe, too.

III. Proto-Indo-Iranian

Before the emergence of Proto-Indo-Iranian, it seems that Pre-Proto-Indo-Iranian-speaking Poltavka groups were subjected to pressure from Central_Steppe_EMBA-related peoples coming from the (south-?)east, such as those found sampled from Mereke_BA. Their ‘kurgan’ culture was dated correctly to approximately the same date as Poltavka materials, but their ancestry and hg. N2(pre-N2a) – also found in a previous sample from Botai – point to their intrusive nature, and thus to difficulties in the Pre-Proto-Indo-Iranian community to keep control over the previous East Yamnaya territory in the Don-Volga-Ural steppes.

We know that the region does not show genetic continuity with a previous period (or was not under this ‘eastern’ pressure) because of an Eastern Yamnaya sample from the same site (ca. 3100 BC) showing typical Yamnaya ancestry. Before Yamnaya, it is likely that Pre-Yamnaya ancestry formed through admixture of EHG-like Khvalynsk with a North Caspian steppe population similar to the Steppe_Eneolithic samples from the North Caucasus Piedmont (see Anthony 2019), so we can also rule out some intermittent presence of a Botai/Kelteminar-like population in the region during the Khvalynsk period.

It is very likely, then, that this competition for the same territory – coupled with the known harsher climate of the late 3rd millennium BC – led Poltavka herders to their known joint venture with Abashevo chiefs in the formation of the Sintashta-Potapovka-Filatovka community of fortified settlements. Supporting these intense contacts of Poltavka herders with Central Asian populations, late ‘outliers’ from the Volga-Ural region show admixture with typical Central_Steppe_MLBA populations: one in Potapovka (ca. 2220 BC), of hg. R1b-Z2103; and four in the Sintashta_MLBA_o1 cluster (ca. 2050-1650 BC), with two samples of hg. R1b-L23 (one R1b-Z2109), one Q1b-L56(xL53), one Q1b-Y6798.

central-steppe-pastoralists
Outlier analysis reveals ancient contacts between sites. We plot the average of principal component 1 (x axis) and principal component 2 (y axis) for the West Eurasian and All Eurasian PCA plots (…). In the Middle to Late Bronze Age Steppe, we observe, in addition to the Western_Steppe_MLBA and Central_Steppe_MLBA clusters (indistinguishable in this projection), outliers admixed with other ancestries. The BMAC-related admixture in Kazakhstan documents northward gene flow onto the Steppe and confirms the Inner Asian Mountain Corridor as a conduit for movement of people.

Similar to how the Sintashta_MLBA_o2 cluster shows an admixture with central steppe populations and hg. R1a-Z645, the WSHG ancestry in those outliers from the o1 cluster of typically (or potentially) Yamnaya lineages show that Poltavka-like herders survived well after centuries of Abashevo-Poltavka coexistence and admixture events, supporting the formation of a Proto-Indo-Iranian community from the local language as pronounced by the incomers, who dominated as elites over the fortified settlements.

The Proto-Indo-Iranian community likely formed thus in situ in the Don-Volga-Ural region, from the admixture of locals of Yamnaya ancestry with incomers of Corded Ware ancestry – represented by the ca. 67% Yamnaya-like ancestry and ca. 33% ancestry from the European cline. Their community formed thus ca. 1,000 years later than the expansion of Late PIE ca. 3500 BC, and expanded (some 500 years after that) a full-fledged Proto-Indo-Iranian language with the Srubna-Andronovo horizon, further admixing with ca. 9% of Central_Steppe_EMBA (WSHG-related) ancestry in their migration through Central Asia, as reported in the paper.

IV. Armenian

The sample from Hajji Firuz, of hg. R1b-Z2103 (xPF331), has been – as expected – re-dated to the Iron Age (ca. 1193-1019 BC), hence it may offer – together with the samples from the Levant and their Aegean-like ancestry rapidly diluted among local populations – yet another proof of how the Late Bronze Age upheaval in Europe was the cause of the Armenian migration to the Armenoid homeland, where they thrived under the strong influence from Hurro-Urartian.

middle-east-armenia-y-dna
Y-chromosome haplogroups of the Middle East and neighbouring groups during the Late Bronze Age / Iron Age. See full maps.

Indus Valley Civilization and Dravidian

A surprise came from the analysis reported by Shinde et al. (2019) of an Iran_N-related IVC ancestry which may have split earlier than 10000 BC from a source common to Iran hunter-gatherers of the Belt Cave.

For the controversial Elamo-Dravidian hypothesis of the Muscovite school, this difference in ancestry between both groups (IVC and Iran Neolithic) seems to be a death blow, if population genomics was even needed for that. Nevertheless, I guess that a full rejection of a recent connection will come down to more recent and subtle population movements in the area.

EDIT (12 SEP): Apparently, Iosif Lazaridis is not so sure about this deep splitting of ‘lineages’ as shown in the paper, so we may be talking about different contributions of AME+ANE/ENA, which means the Elamo-Dravidian game is afoot; at least in genomics:

I shared the idea that the Indus Valley Civilization was linked to the Proto-Dravidian community, so I’m inclined to support this statement by Narasimhan, Patterson, et al. (2019), even if based only on modern samples and a few ancient ones:

The strong correlation between ASI ancestry and present-day Dravidian languages suggests that the ASI, which we have shown formed as groups with ancestry typical of the Indus Periphery Cline moved south and east after the decline of the IVC to mix with groups with more AASI ancestry, most likely spoke an early Dravidian language.

india-steppe-indus-valley-andamanese-ancestry
Natural neighbour interpolation of qpAdm results – Maximum A Posteriori Estimate from the Hierarchical Model (estimates used in the Narasimhan, Patterson et al. 2019 figures) for Central_Steppe_MLBA-related (left), Indus_Periphery_West-related (center) and Andamanese_Hunter-Gatherer-related ancestry (right) among sampled modern Indian populations. In blue, peoples of IE language; in red, Dravidian; in pink, Tibeto-Burman; in black, unclassified. See full image.

I am wary of this sort of simplistic correlation with modern speakers, because we have seen what happened with the wrong assumptions about modern Balto-Slavic and Finno-Ugric speakers and their genetic profile (see e.g. here or here). In fact, I just can’t differentiate as well as those with deep knowledge in South Asian history the social stratification of the different tribal groups – with their endogamous rules under the varna and jati systems – in the ancestry maps of modern India. The pattern of ancestry and language distribution combined with the findings of ancient populations seem in principle straightforward, though.

Conclusion

The message to take home from Shinde et al. (2019) is that genomic data is fully at odds with the Anatolian homeland hypothesis – including the latest model by Heggarty (2014)* – whose relevance is still overvalued today, probably due in part to the shift of OIT proponents to more reasonable Out-of-Iran models, apparently more fashionable as a vector of Indo-Aryan languages than Eurasian steppe pastoralists?
*The authors listed this model erroneously as Heggarty (2019).

The paper seems to play with the occasional reference to Corded Ware as a vector of expansion of Indo-European languages, even after accepting the role of Yamnaya as the most evident population expanding Late PIE to western Europe – and the different ancestry that spread with Indo-Iranian to South Asia 1,000 years later. However, the most cringe-worthy aspect is the sole citation of the debunked, pseudoscientific glottochronological method used by Ringe, Warnow, and Taylor (2002) to support the so-called “steppe homeland”, a paper and dialectal scheme which keeps being referenced in papers of the Reich Lab, probably as a consequence of its use in Anthony (2007).

On the other hand, these are the equivalent simplistic comments in Narasimhan, Patterson et al. (2019):

The Steppe ancestry in South Asia has the same profile as that in Bronze Age Eastern Europe, tracking a movement of people that affected both regions and that likely spread the unique features shared between Indo-Iranian and Balto-Slavic languages. (…), which despite their vast geographic separation share the “satem” innovation and “ruki” sound laws.

mallory-adams-tree
Indo-European dialectal relationships, from Mallory and Adams (2006).

The only academic closely related to linguistics from the list of authors, as far as I know, is James P. Mallory, who has supported a North-West Indo-European dialect (including Balto-Slavic) for a long time – recently associating its expansion with Bell Beakers – opposed thus to a Graeco-Aryan group which shared certain innovations, “Satemization” not being one of them. Not that anyone needs to be a linguist to dismiss any similarities between Balto-Slavic and Indo-Iranian beyond this phonetic trend, mind you.

Even Anthony (2019) supports now R1b-rich Pre-Yamnaya and Yamnaya communities from the Don-Volga region expanding Middle and Late Proto-Indo-European dialects.

So how does the underlying Corded Ware ancestry of eastern Europe (where Pre-Balto-Slavs eventually spread to from Bell Beaker-derived groups) and of the highly admixed (“cosmopolitan”, according to the authors) Sintashta-Potapovka-Filatovka in the east relate to the similar-but-different phonetic trends of two unrelated IE dialects?

If only there was a language substrate that could (as Shinde et al. put it) “elegantly” explain this similar phonetic evolution, solving at the same time the question of the expansion of Uralic languages and their strong linguistic contacts with steppe peoples. Say, Eneolithic populations of mainly hunter-fisher-gatherers from the North Pontic forest-steppes with a stronger connection to metalworking

Related

Munda admixture happened probably during the ANI-ASI mixture

language-tree-munda

Preprint The genetic legacy of continental scale admixture in Indian Austroasiatic speakers, by Tätte et al. bioRxiv (2018).

Interesting excerpts:

Studies analysing mtDNA and Y chromosome markers have revealed a sex-specific admixture pattern of admixture of Southeast and South Asian ancestry components for Munda speakers. While close to 100% of mtDNA lineages present in Mundas match those in other Indian populations, around 65% of their paternal genetic heritage is more closely related to Southeast Asian than South Asian variation. Such a contrasting distribution of maternal and paternal lineages among the Munda speakers is a classic example of ‘father tongue hypothesis’. However, the temporality of this expansion is contentious. Based on Y-STR data the coalescent time of Indian O2a-M95 haplogroup was estimated to be >10 KYA. Recently, the reconstructed phylogeny of 8.8 Mb region of Y chromosome data showed that Indian O2a-M95 lineages coalesce within a clade nested within East/Southeast Asian within the last ~5-7 KYA. This date estimate sets the upper boundary for the main episode of gene flow of Y chromosomes from Southeast Asia to India.

munda-pca
Supplementary Figure S4. First two components of principal component analysis (PCA). Individuals and population medians (circles) are marked with abbreviations from population names. Different colours represent populations from different geographic areas and/or linguistic groups as shown on the legend on the right. For the full names of populations see Supplementary Table S1. PCA was performed using software EIGENSOFT 6.1.42 on the whole filtered dataset (1072 individuals), previously LD pruned as described in the title of Supplementary Figure S1. The first two principal components describe 5.13% and 2.57% of total variance.

Admixture proportions suggest a novel scenario

Regardless of which West Asian population we used, we found that Munda speakers can be described on average as a mixture of ~19% Southeast Asian, 15% West Asian and 66% Onge (South Asian) components. Alternatively, the West and South Asian components of Munda could be modelled using a single South Asian population (Paniya), accounting on average to 77% of the Munda genome. When rescaling the West and South Asian (Onge) components to 1 to explore the Munda genetic composition prior to the introduction of the Southeast Asian component, we note that the West Asian component is lower (~19%) in Munda compared to Paniya (27%) (Supplementary Table S4: *Average_Lao=0). Consistently with qpGraph analyses in Narasimhan et al. (2018), this may point to an initial admixture of a Southeast Asian substrate with a South Asian substrate free of any West Asian component, followed by the encounter of the resulting admixed population with a Paniya-like population. Such a scenario would imply an inverse relationship between the Southeast and West Asian relative proportions in Munda or, in other words, the increase of Southeast Asian component should cause a greater reduction of the West Asian compared to the reduction in the South Asian component in Munda.

admixture-munda-india
The distribution of genetic components (K=13) based on the global ADMIXTURE analysis (Supplementary Figure S1, S2, S3) for a subset of populations on a map of South and Southeast Asia. The circular legend in the bottom left corner shows the ancestral components corresponding to the colours on pie charts. The sector sizes correspond to population median.

Dating the admixture event

In this study, we have replicated a result previously reported in Chaubey et al. (2011)7 that the Mundas lack one ancestral component (k2) that is characteristic to Indian Indo-European and Dravidian speaking populations. If this component came to India through one of the Indo-Aryan migrations then it would be fair to presume that the Munda admixture happened before this component reached India or at least before it spread all over the country. However, the admixture time computed here, falls in the exact same timeframe as the ANI-ASI mixture has been estimated to have happened in India through which the k2 component probably spread. Therefore, we propose that if the Munda admixture happened at the same time, it is possible for it to have happened in the eastern part of the country, east of Bangladesh, and later when populations from East Asia moved to the area, the Mundas migrated towards central India. Such a scenario, which may be further clarified by ancient DNA analyses, seems to be further supported by the fact that Mundas harbor a smaller fraction of West Asian ancestry compared to contemporary Paniya (Supplementary Table S4) and cannot therefore be seen as a simple admixture product of Southern Indian populations with incoming Southeast Asian ancestries.

namazga-expansion-south-asia
Image from Damgaard et al. (2018). A summary of the four qpAdm models fitted for South Asian populations. For each modern South Asian population. we fit different models with qpAdm to explain their ancestry composition using ancient groups and present the f irst model that we could not reject in the following priority order: 1. Namazga_CA + Onge, 2. Namazga_CA + Onge + Late Bronze Age Steppe, 3. Namazga_CA + Onge + Xiongnu_lA (East Asian proxy). and 4. Turkmenistan_lA + Xiongnu_lA. Xiongnu_lA were used here to represent East Asian ancestry. We observe that while South Asian Dravidian speakers can be modeled as a mixture of Onge and Namazga_CA. an additional source related to Late Bronze Age steppe groups is required for IE speakers. In Tibeto-Burman and Austro-Asiatic speakers. an East Asian rather than a Steppe_MLBA source is required

Linguistics and genome-wide data

(…) by and large, the linguistic classification justifies itself but Kharia and Juang do not fit in this simplification perfectly.

Once again, with the current level of detail in genetic studies, there is often no clear dialectal division possible for certain groups without fine-scale population studies, and the help from linguistics and archaeology.

Featured image from open access paper by Chaubey et al. (2011).

Related

Modelling of prehistoric dispersal of rice varieties in India point to a north-western origin

rice-dispersal

New paper (behind paywall), A tale of two rice varieties: Modelling the prehistoric dispersals of japonica and proto-indica rices, by Silva et al., The Holocene (2018).

Interesting excerpts (emphasis mine):

Materials

Our empirical evidence comes from the Rice Archaeological Database (RAD). The first version of this database was used for a synthesis of rice dispersal by Fuller et al. (2010), a slightly expanded dataset (version 1.1) was used to model the dispersal of rice, land area under wet rice cultivation and associated methane emissions from 5000–1000 BP (Fuller et al., 2011). The present dataset (version 2) was used in a previous analysis of the origins of rice domestication (Silva et al., 2015). The database records sites and chronological phases within sites where rice has been reported, including whether rice was identified from plant macroremains, phytoliths or impressions in ceramics. Ages are recorded as the start and end date of each phase, and a median age of the phase is then used for analysis. Dating is based on radiocarbon evidence (…)

Modelling framework

Our approach expands on previous efforts to model the geographical origins, and subsequent spread, of japonica rice (Silva et al., 2015). The methodology is based on the explicit modelling of dispersal hypotheses using the Fast Marching algorithm, which computes the cost-distance of an expanding front at each point of a discrete lattice or raster from the source(s) of diffusion (Sethian, 1996; Silva and Steele, 2012, 2014). Sites in the RAD database are then queried for their cost-distance, the distance from the source(s) of dispersal along the cost-surface that represents the hypothesis being modelled (see Connolly and Lake, 2006; Douglas, 1994; Silva et al., 2015; Silva and Steele, 2014 for more on this approach) and, together with the site’s dating, used for regression analysis. (…)

india-japonica-rice
Predicted arrival times of the non-shattering rice variety (japonica or the hybrid indica) across southern Asia based on best-fitting model H2. Included are also sites with known presence of non-shattering spikelet bases (see text).

Model and results

The ‘Inner Asia Mountain Corridor’ hypothesis (H2) therefore predicts japonica rice to arrive first in northwest India via a route that starts in the Yellow river valley, travels west via the well-known Hexi corridor, then just south of the Inner Asian Mountains and thence to India.

The results also show that the addition of the Inner Asia Mountain Corridor significantly improves the model’s fit to the data, particularly model H2 where rice is introduced to the Indian subcontinent exclusively via a trade route that circumvents the Tibetan plateau. This agrees with independent archaeological evidence that sees millets spread westwards along this corridor perhaps as early as 3000 BC (e.g. Boivin et al., 2012; Kohler-Schneider and Canepelle, 2009; Rassamakin, 1999) and certainly by 2500–2000 BC (Frachetti et al., 2010; Spengler 2015; Stevens et al., 2016), that is, in the same time frame as that predicted for rice in model H2. The arrival of western livestock (sheep, cattle) into central China, 2500–2000 BC (Fuller et al., 2011; Yuan and Campbell, 2009), and wheat, ca. 2000 BC (Betts et al., 2014; Flad et al., 2010; Stevens et al., 2016; Zhao, 2015), add evidence for the role of the Inner Asia Mountain Corridor for domesticated species dispersal in this period.

Conclusion

Through a combination of explicit spatial modelling and simulation, we have demonstrated the high likelihood that dispersal of rice via traders in Central Asia introduced japonica rice into South Asia. Only slightly less likely is a combination of introduction via two routes including a Central Asia to Pakistan/northwestern India route as well as introduction to northeastern India directly from China/Myanmar. However, there is a very low probability that current archaeological evidence for rice fits with a single introduction of japonica into India via the northeast. We have also simulated the minimum amount of archaeobotanical sampling from the Neolithic (to Bronze Age) period in the regions of northeastern India and Myanmar that will be necessary to strengthen support for the combined introduction (model H3) or a single Central Asian introduction (model H2).

Related

“Steppe people seem not to have penetrated South Asia”

indo-iranian-sintashta-uralic-migrations

Open access structured abstract for The first horse herders and the impact of early Bronze Age steppe expansions into Asia from Damgaard et al. Science (2018) 360(6396):eaar7711.

Abstract (emphasis mine):

The Eurasian steppes reach from the Ukraine in Europe to Mongolia and China. Over the past 5000 years, these flat grasslands were thought to be the route for the ebb and flow of migrant humans, their horses, and their languages. de Barros Damgaard et al. probed whole-genome sequences from the remains of 74 individuals found across this region. Although there is evidence for migration into Europe from the steppes, the details of human movements are complex and involve independent acquisitions of horse cultures. Furthermore, it appears that the Indo-European Hittite language derived from Anatolia, not the steppes. The steppe people seem not to have penetrated South Asia. Genetic evidence indicates an independent history involving western Eurasian admixture into ancient South Asian peoples.

INTRODUCTION
According to the commonly accepted “steppe hypothesis,” the initial spread of Indo-European (IE) languages into both Europe and Asia took place with migrations of Early Bronze Age Yamnaya pastoralists from the Pontic-Caspian steppe. This is believed to have been enabled by horse domestication, which revolutionized transport and warfare. Although in Europe there is much support for the steppe hypothesis, the impact of Early Bronze Age Western steppe pastoralists in Asia, including Anatolia and South Asia, remains less well understood, with limited archaeological evidence for their presence. Furthermore, the earliest secure evidence of horse husbandry comes from the Botai culture of Central Asia, whereas direct evidence for Yamnaya equestrianism remains elusive.

RATIONALE
We investigated the genetic impact of Early Bronze Age migrations into Asia and interpret our findings in relation to the steppe hypothesis and early spread of IE languages. We generated whole-genome shotgun sequence data (~1 to 25 X average coverage) for 74 ancient individuals from Inner Asia and Anatolia, as well as 41 high-coverage present-day genomes from 17 Central Asian ethnicities.

damgaard-south-asia
Model-based admixture proportions for selected ancient and present-day individuals, assuming K = 6, shown with their corresponding geographical locations. Ancient groups are represented by larger admixture plots, with those sequenced in the present work surrounded by black borders and others used for providing context with blue borders. Present-day South Asian groups are represented by smaller admixture plots with dark red borders.

RESULTS
We show that the population at Botai associated with the earliest evidence for horse husbandry derived from an ancient hunter-gatherer ancestry previously seen in the Upper Paleolithic Mal’ta (MA1) and was deeply diverged from the Western steppe pastoralists. They form part of a previously undescribed west-to-east cline of Holocene prehistoric steppe genetic ancestry in which Botai, Central Asians, and Baikal groups can be modeled with different amounts of Eastern hunter-gatherer (EHG) and Ancient East Asian genetic ancestry represented by Baikal_EN.

In Anatolia, Bronze Age samples, including from Hittite speaking settlements associated with the first written evidence of IE languages, show genetic continuity with preceding Anatolian Copper Age (CA) samples and have substantial Caucasian hunter-gatherer (CHG)–related ancestry but no evidence of direct steppe admixture.

In South Asia, we identified at least two distinct waves of admixture from the west, the first occurring from a source related to the Copper Age Namazga farming culture from the southern edge of the steppe, who exhibit both the Iranian and the EHG components found in many contemporary Pakistani and Indian groups from across the subcontinent. The second came from Late Bronze Age steppe sources, with a genetic impact that is more localized in the north and west.

CONCLUSION
Our findings reveal that the early spread of Yamnaya Bronze Age pastoralists had limited genetic impact in Anatolia as well as Central and South Asia. As such, the Asian story of Early Bronze Age expansions differs from that of Europe. Intriguingly, we find that direct descendants of Upper Paleolithic hunter-gatherers of Central Asia, now extinct as a separate lineage, survived well into the Bronze Age. These groups likely engaged in early horse domestication as a prey-route transition from hunting to herding, as otherwise seen for reindeer. Our findings further suggest that West Eurasian ancestry entered South Asia before and after, rather than during, the initial expansion of western steppe pastoralists, with the later event consistent with a Late Bronze Age entry of IE languages into South Asia. Finally, the lack of steppe ancestry in samples from Anatolia indicates that the spread of the earliest branch of IE languages into that region was not associated with a major population migration from the steppe.

I think the wording of the abstract is weird, but consequent with their samples and results, so probably just clickbait / citebait for Indian journalists and social networks, or maybe a new attempt to ‘show respect for the sensibilities of Indians’ related to the artificially magnified “AIT vs. OIT” controversy, that is only present in India.

However, everything is possible, since it is brought to you by the same Danish group who proposed the Yamnaya ancestral component™, the CHG = Indo-European (and simultaneously EHG in Maykop = Anatolian??), and now also the CWC/R1a = Indo-European & Volosovo = Uralic

Here is the reaction of Narasimhan: Narasimhan has deleted the Tweet, it basically questioned the sentence that steppe people did not penetrate South Asia.

Related

South-East Asia samples include shared ancestry with Jōmon

pca-south-east-asia-jomon

New paper (behind paywall) The prehistoric peopling of Southeast Asia, by McColl et al. (Science 2018) 361(6397):88-92 from a recent bioRxiv preprint.

Interesting is this apparently newly reported information including a female sample from the Ikawazu Jōmon of Japan ca. 570 BC (emphasis mine):

The two oldest samples — Hòabìnhians from Pha Faen, Laos [La368; 7950 with 7795 calendar years before the present (cal B.P.)] and Gua Cha, Malaysia (Ma911; 4415 to 4160 cal B.P.)—henceforth labeled “group 1,” cluster most closely with present-day Önge from the Andaman Islands and away from other East Asian and Southeast-Asian populations (Fig. 2), a pattern that differentiates them from all other ancient samples. We used ADMIXTURE (14) and fastNGSadmix (15) to model ancient genomes as mixtures of latent ancestry components (11). Group 1 individuals differ from the other Southeast Asian ancient samples in containing components shared with the supposed descendants of the Hòabìnhians: the Önge and the Jehai (Peninsular Malaysia), along with groups from India and Papua New Guinea.

We also find a distinctive relationship between the group 1 samples and the Ikawazu Jōmon of Japan (IK002). Outgroup f3 statistics (11, 16) show that group 1 shares the most genetic drift with all ancient mainland samples and Jōmon (fig. S12 and table S4). All other ancient genomes share more drift with present-day East Asian and Southeast Asian populations than with Jōmon (figs. S13 to S19 and tables S4 to S11). This is apparent in the fastNGSadmix analysis when assuming six ancestral components (K = 6) (fig. S11), where the Jōmon sample contains East Asian components and components found in group 1. To detect populations with genetic affinities to Jōmon, relative to present-day Japanese, we computed D statistics of the form D(Japanese, Jōmon; X, Mbuti), setting X to be different presentday and ancient Southeast Asian individuals (table S22). The strongest signal is seen when X=Ma911 and La368 (group 1 individuals), showing a marginally nonsignificant affinity to Jōmon (11). This signal is not observed with X = Papuans or Önge, suggesting that the Jōmon and Hòabìnhians may share group 1 ancestry (11).

jomon-japanese-migrations
Model for plausible migration routes into SEA. This schematic is based on ancestry patterns observed in the ancient genomes. Because we do not have ancient samples to accurately resolve how the ancestors of Jōmon and Japanese populations entered the Japanese archipelago, these migrations are represented by dashed arrows. A mainland component in Indonesia is depicted by the dashed red-green line. Gr, group; Kra, Kradai.

(…) Finally, the Jōmon individual is best-modeled as a mix between a population related to group 1/Önge and a population related to East Asians (Amis), whereas present-day Japanese can be modeled as a mixture of Jōmon and an additional East Asian component (Fig. 3 and fig. S29)

Interesting in relation to the oral communication of the SMBE O-03-OS02 Whole genome analysis of the Jomon remain reveals deep lineage of East Eurasian populations by Gakuuhari et al.:

Post late-Paleolithic hunter-gatherers lived throughout the Japanese archipelago, Jomonese, are thought to be a key to understanding the peopling history in East Asia. Here, we report a whole genome sequence (x1.85) of 2,500-year old female excavated from the Ikawazu shell-mound, unearthed typical remains of Jomon culture. The whole genome data places the Jomon as a lineage basal to contemporary and ancient populations of the eastern part of Eurasian continent, and supports the closest relationship with the modern Hokkaido Ainu. The results of ADMIXTURE show the Jomon ancestry is prevalent in present-day Nivkh, Ulchi, and people in the main-island Japan. By including the Jomon genome into phylogenetic trees, ancient lineages of the Kusunda and the Sherpa/Tibetan, early splitting from the rest of East Asian populations, is emerged. Thus, the Jomon genome gives a new insight in East Asian expansion. The Ikawazu shell-mound site locates on 34,38,43 north latitude, and 137,8, 52 east longitude in the central main-island of the Japanese archipelago, corresponding to a warm and humid monsoon region, which has been thought to be almost impossible to maintain sufficient ancient DNA for genome analysis. Our achievement opens up new possibilities for such geographical regions.

Related

Expansion of domesticated goat echoes expansion of early farmers

goat-neolithic

New paper (behind paywall) Ancient goat genomes reveal mosaic domestication in the Fertile Crescent, by Daly et al. Science (2018) 361(6397):85-88.

Interesting excerpts (emphasis mine):

Thus, our data favor a process of Near Eastern animal domestication that is dispersed in space and time, rather than radiating from a central core (3, 11). This resonates with archaeozoological evidence for disparate early management strategies from early Anatolian, Iranian, and Levantine Neolithic sites (12, 13). Interestingly, our finding of divergent goat genomes within the Neolithic echoes genetic investigation of early farmers. Northwestern Anatolian and Iranian human Neolithic genomes are also divergent (14–16), which suggests the sharing of techniques rather than large-scale migrations of populations across Southwest Asia in the period of early domestication. Several crop plants also show evidence of parallel domestication processes in the region (17).

PCA affinity (Fig. 2), supported by qpGraph and outgroup f3 analyses, suggests that modern European goats derive from a source close to the western Neolithic; Far Eastern goats derive from early eastern Neolithic domesticates; and African goats have a contribution from the Levant, but in this case with considerable admixture from the other sources (figs. S11, S16, and S17 and tables S26 and 27). The latter may be in part a result of admixture that is discernible in the same analyses extended to ancient genomes within the Fertile Crescent after the Neolithic (figs. S18 and S19 and tables S20, S27, and S31) when the spread of metallurgy and other developments likely resulted in an expansion of inter-regional trade networks and livestock movement.

goat-middle-east
Maximumlikelihood phylogeny and geographical distributions of ancient mtDNA haplogroups. (A) A phylogeny placing ancient whole mtDNA sequences in the context of known haplogroups. Symbols denoting individuals are colored by clade membership; shape indicates archaeological period (see key). Unlabeled nodes are modern bezoar and outgroup sequence (Nubian ibex) added for reference.We define haplogroup T as the sister branch to the West Caucasian tur (9). (B and C) Geographical distributions of haplogroups show early highly structured diversity in the Neolithic period (B) followed by collapse of structure in succeeding periods (C).We delineate the tiled maps at 7250 to 6950 BP, a period >bracketing both our earliest Chalcolithic sequence (24, Mianroud) and latest Neolithic (6, Aşağı Pınar). Numbered archaeological sites also include Direkli Cave (8), Abu Ghosh (9), ‘Ain Ghazal (10), and Hovk-1 Cave (11) (table S1) (9).

Our results imply a domestication process carried out by humans in dispersed, divergent, but communicating communities across the Fertile Crescent who selected animals in early millennia, including for pigmentation, the most visible of domestic traits.

Related

Reconstruction of Y-DNA phylogeny helps also reconstruct Tibeto-Burman expansion

tibeto-burman-han-chinese-population

New paper (behind paywall) Reconstruction of Y-chromosome phylogeny reveals two neolithic expansions of Tibeto-Burman populations by Wang et al. Mol Genet Genomics (2018).

Interesting excerpts:

Archeological studies suggest that a subgroup of ancient populations of the Miaodigou culture (~ 6300–5500 BP) moved westward to the upper stream region of the Yellow River and created the Majiayao culture (~ 5400–4900 BP) (Liu et al. 2010), which was proposed to be the remains of direct ancestors of Tibeto-Burman populations (Sagart 2008). On the other hand, Han populations, the other major descendant group of the Yang-Shao culture (~ 7000–5500 BP), are composed of many other sub-lineages of Oα-F5 and extremely low frequencies of D-M174 (Additional files 1: Figure S1; Additional files 2: Table S1). Therefore, we propose that Oα-F5 may be one of the dominant paternal lineages in ancient populations of Yang-Shao culture and its successors.

In this study, we demonstrated that both sub-lineages of D-M174 and Oα-F5 are founding paternal lineages of modern Tibeto-Burman populations. The genetic patterns suggested that the ancestor group of modern Tibeto-Burman populations may be an admixture of two distinct ancient populations. One of them may be hunter–gatherer populations who survived on the plateau since the Paleolithic Age, represented by varied sub-lineages of sub-lineages of D-M174. The other one was comprised of farmers who migrated from the middle Yellow River basin, represented by sub-lineages of Oα-F5. In general, the genetic evidence in this study supports the conclusion that the appearance of the ancestor group of Tibeto-Burman populations was triggered by the Neolithic expansion from the upper-middle Yellow River basin and admixture with local populations on the Tibetan Plateau (Su et al. 2000).

tibeto-burman-phylogenetic-tree
Simplified phylogenetic tree showing sample locations. The size of the circle for each sampling location corresponds to the number of samples

Two neolithic expansion origins of Tibeto‑Burman populations

We also observed significant differences in the paternal gene pool of different subgroups of Tibeto-Burman populations. Haplogroup D-M174 contributed ~ 54% percent in a sampling of 2354 Tibetan males throughout the Tibetan Plateau (Qi et al. 2013). Previous studies have also found high frequencies of D-M174 in other populations on the Tibetan Plateau (Shi et al. 2008), including Sherpa (Lu et al. 2016) and Qiang (Wang et al. 2014). In contrast, haplogroup D-M174 is rare or absent from Tibeto-Burman populations from Northeast India and Burma (Shi et al. 2008). In populations of the Ngwi-Burmese language subgroup, the average frequencies of haplogroup D-M174 are ~ 5% (Dong et al. 2004; Peng et al. 2014). Furthermore, we found that lineage Oα1c1b-CTS5308 is mainly found in Tibeto-Burman populations from the Tibetan Plateau. In contrast, lineage Oα1c1a-Z25929 was found in Tibeto-Burman populations from Northeast India, Burma, and the Yunan and Hunan provinces of China (Additional files 1: Figure S1; Additional files 2: Table S1). In general, enrichment of lineage Oα1c1b- CTS5308 and high frequencies of D-M174 can be found in most Tibeto-Burman populations on the Tibetan Plateau and adjacent regions, whereas Tibeto-Burman populations from other regions tend to have lineage Oα1c1a-Z25929 and a little to no percentage of D-M174.

The inconsistent pattern we observed in the paternal gene pool of modern Tibeto-Burman populations suggested that there may be two distinct ancestor groups (Fig. 3). The proposed migration routes shown in Fig. 3 are somewhat different from those proposed by Su et al. (2000). According to our age estimation, most of the D1a2a-P47 samples belong to sub-lineage PH116, a young lineage that emerged ~ 2500 years ago (95% CI 1915–3188 years). On the other hand, continuous differentiation can be observed on a phylogenetic tree of lineages D1a1a1a1-PH4979 and D1a1a1a2-Z31591 since 6000 years ago. Therefore, we proposed that a group of ancient populations may have moved to the upper basin of the Yellow River and admixed intensively with local populations with high frequencies of haplogroup D-M174, including its sub-lineage D1a2a-P47 (Fig. 3). This ancestor group eventually gave birth to modern Tibeto-Burman populations on the Tibetan Plateau and adjacent regions. The other ancestor group moved toward the southwest and finally reached South East Asia (Burma and other locations) and the northeastern part of India (Fig. 3). This ancestor group may have had no or a minor admixture of D-M174 in their paternal gene pool.

tibeto-burman-migrations
Two proposed ancestor groups and migration routes for Tibeto-Burman populations

Long‑term admixture before expansion to a high‑altitude region

It is interesting to investigate the time gap between the appearance of Neolithic cultures in the northeastern part of the Tibetan Plateau and the final phase of human expansion across the Tibetan Plateau. The Majiayao culture (~ 5400–4900 BP) is the earliest Neolithic culture in the northeastern part of the Tibetan Plateau (Liu et al. 2010). However, previous archeological study has suggested that the final phase of diffusion into the high-altitude area of the Tibetan Plateau occurred at approximately 3.6 kya (Chen et al. 2015). Our genetic evidence in this study is consistent with this scenario based on archeological evidence. Based on Y-chromosome analysis in this study, many unique lineages of Tibeto-Burman populations emerged between 6000 years ago and 2500 years ago (Additional files 3: Table S2). The most recent common age of D1a2-PH116, a sub-lineage that spread throughout the Tibetan Plateau, is only 2500 years ago.

We propose that there may be two important factors for the observed age gap. First, living in a high-altitude environment may require some crucial physical characteristics that were lacking from Neolithic immigrants from the middle Yellow River Basin. Intense genetic admixture with local people who had survived on the Tibetan Plateau since the Paleolithic Age may have actually guaranteed the expansion of humans across the Tibetan Plateau. Therefore, a long period of admixture, lasting from 5.4 to 3.6 kya, may be necessary for the appearance of a population with beneficial genetic variants that was genetically adapted to the high-altitude environment. Second, technological innovations, such as the domestication of wheat and highland barley (Chen et al. 2015), establishment of yak pastoralism (Rhode et al. 2007), and introduction of other culture elements in the Bronze Age (Ma et al. 2016), are also important factors that facilitated permanent settlements with large population sizes in the high-altitude area of the Tibetan Plateau.

Related:

Complex history of dog origins and translocations in the Pacific revealed by ancient mitogenomes

remote-oceania-vanuatu-lapita

Open access Complex history of dog (Canis familiaris) origins and translocations in the Pacific revealed by ancient mitogenomes, by Creig et al., Scientific Reports (2018).

Abstract:

Archaeological evidence suggests that dogs were introduced to the islands of Oceania via Island Southeast Asia around 3,300 years ago, and reached the eastern islands of Polynesia by the fourteenth century AD. This dispersal is intimately tied to human expansion, but the involvement of dogs in Pacific migrations is not well understood. Our analyses of seven new complete ancient mitogenomes and five partial mtDNA sequences from archaeological dog specimens from Mainland and Island Southeast Asia and the Pacific suggests at least three dog dispersal events into the region, in addition to the introduction of dingoes to Australia. We see an early introduction of dogs to Island Southeast Asia, which does not appear to extend into the islands of Oceania. A shared haplogroup identified between Iron Age Taiwanese dogs, terminal-Lapita and post-Lapita dogs suggests that at least one dog lineage was introduced to Near Oceania by or as the result of interactions with Austronesian language speakers associated with the Lapita Cultural Complex. We did not find any evidence that these dogs were successfully transported beyond New Guinea. Finally, we identify a widespread dog clade found across the Pacific, including the islands of Polynesia, which likely suggests a post-Lapita dog introduction from southern Island Southeast Asia.

canis-familiaris
A map of Southeast Asia and the Pacific showing the source location of the specimens and associated haplogroups (assignment to haplogroup follows Duleba and colleagues) and the median-joining network. The boundary between Near and Remote Oceania is also shown. Symbols identify the type of sequence: filled circle, ancient mitogenome; half circle, partial ancient sequence; hollow circle, modern mitogenome. Node colours represent the haplogroup, grey, A; red, A2b2, green, A2b3; yellow, A4’5; blue, B.

Conclusion:

The dispersal of dogs across the Pacific is inseparably linked to the relationships between dogs and people. Unlike movement across continental landmasses, Pacific dogs must have been transported by people across the waters that separate islands. The ancient mitogenomes sequenced from archaeological dog specimens presented here offer a novel series of individual insights into the history of dog translocation from Southeast Asia as it occurred prior to the influence of modern European dog breeds. We generated seven mitogenomes and five partial sequences from ancient MSEA, ISEA and Pacific dogs, and four modern dingoes. Despite the small sample size, our results reveal levels of complexity and discontinuity in the introduction and movement of dogs, which are mirrored in the archaeological and linguistic evidence, suggesting at least three introductions of dogs to the wider Pacific region, in addition to the earlier appearance of the dingo in Australia. Further mtDNA studies of ancient dogs and modern village populations throughout the region may contribute additional data that can be used to evaluate these hypothesised dispersals. Autosomal and Y-chromosome analyses also have the potential to generate additional information about dog dispersal, which could reveal different dispersal signatures based on sex, or phenotypic characteristics, though the environmental conditions in the region are not particularly conducive to aDNA preservation.

Our molecular genetic analyses reveal one of the earliest dogs present in ISEA around 3,000 years ago from Timor-Leste possesses a mtDNA lineage not found elsewhere in the region. We also found similarities between mtDNA of modern dingoes and NGSDs and an ancient Taiwanese sequence, which supports previous observations about possible links between Y-chromosome markers of modern dingoes and a modern Taiwanese sample. More work is required to address whether these connections reflect the genetic diversity of a shared ancestral population in mainland China, or attest to a currently unknown dispersal event linking the two populations. Archaeological evidence for the introduction of dogs to Oceania as part of the LCC is extremely limited. Nonetheless, we demonstrate that mitogenomes from dogs in terminal Lapita and post-Lapita levels of archaeological sites along the south coast of mainland New Guinea also show affinities with an Iron Age dog specimen from Taiwan, raising the possibility of at least one introduction of dogs during Austronesian expansions ultimately from the north. Finally, we have identified a major late introduction of dogs across the islands of Oceania beginning around 2,000 years ago, which appears to have originated in MSEA, not Taiwan, and culminated in the establishment of dog populations in initial colonisation-era sites throughout East Polynesia.

phylogenetic-dingo
Molecular phylogenetic analysis by maximum likelihood method, implemented in MEGA71. The evolutionary history shown inferred by using the maximum likelihood method based on the Hasegawa-Kishino-Yano model. The tree with the highest log likelihood (-25257.5243) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach, and then selecting the topology with superior log likelihood value. A discrete Gamma distribution was used to model evolutionary rate differences among sites (5 categories (+G, parameter = 0.0500)). The rate variation model allowed for some sites to be evolutionarily invariable ([+I], 0.0010% sites). The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The analysis involved 45 nucleotide sequences. There were a total of 16774 positions in the final dataset.

Also related, open access Elucidating biogeographical patterns in Australian native canids using genome wide SNPs, by Cairns et al., PLOS One (2018).

Abstract:

Dingoes play a strong role in Australia’s ecological framework as the apex predator but are under threat from hybridization and agricultural control programs. Government legislation lists the conservation of the dingo as an important aim, yet little is known about the biogeography of this enigmatic canine, making conservation difficult. Mitochondrial and Y chromosome DNA studies show evidence of population structure within the dingo. Here, we present the data from Illumina HD canine chip genotyping for 23 dingoes from five regional populations, and five New Guinea Singing Dogs to further explore patterns of biogeography using genome-wide data. Whole genome single nucleotide polymorphism (SNP) data supported the presence of three distinct dingo populations (or ESUs) subject to geographical subdivision: southeastern (SE), Fraser Island (FI) and northwestern (NW). These ESUs should be managed discretely. The FI dingoes are a known reservoir of pure, genetically distinct dingoes. Elevated inbreeding coefficients identified here suggest this population may be genetically compromised and in need of rescue; current lethal management strategies that do not consider genetic information should be suspended until further data can be gathered. D statistics identify evidence of historical admixture or ancestry sharing between southeastern dingoes and South East Asian village dogs. Conservation efforts on mainland Australia should focus on the SE dingo population that is under pressure from domestic dog hybridization and high levels of lethal control. Further data concerning the genetic health, demographics and prevalence of hybridization in the SE and FI dingo populations is urgently needed to develop evidence based conservation and management strategies.

dingo-australia-pca
Principal components analysis (PCA) based upon filtered whole genome SNP genotypes (58,512 sites) for 23 dingoes, 5 NGSD, 8 Borneo village dogs, 9 Vietnam village dogs, 10 Portugal village dogs and 8 Australian cattle dogs (‘Dataset B’). Colours represent population clusters: red for SE dingoes, purple for FI dingoes, blue for NW dingoes, dark green for NGSD, light green for Borneo village dogs, orange for Vietnam village dogs, yellow for Portugal village dogs and grey for Australian cattle dogs. (A) PC 1 versus PC 2. (B) PC 1 versus PC 3.

As I said in a previous post, the study of dogs may be useful to trace population migrations and to assess strong cultural contacts. Especially, as in this case, when crossbreeding among cultures is not easy…

Related: