Uralic speakers formed clines of Corded Ware ancestry with WHG:ANE populations

steppe-forest-tundra-biomes-uralic

The preprint by Jeong et al. (2018) has been published: The genetic history of admixture across inner Eurasia Nature Ecol. Evol. (2019).

Interesting excerpts, referring mainly to Uralic peoples (emphasis mine):

A model-based clustering analysis using ADMIXTURE shows a similar pattern (Fig. 2b and Supplementary Fig. 3). Overall, the proportions of ancestry components associated with Eastern or Western Eurasians are well correlated with longitude in inner Eurasians (Fig. 3). Notable outliers include known historical migrants such as Kalmyks, Nogais and Dungans. The Uralic- and Yeniseian-speaking populations, as well as Russians from multiple locations, derive most of their Eastern Eurasian ancestry from a component most enriched in Nganasans, while Turkic/Mongolic speakers have this component together with another component most enriched in populations from the Russian Far East, such as Ulchi and Nivkh (Supplementary Fig. 3). Turkic/Mongolic speakers comprising the bottom-most cline have a distinct Western Eurasian ancestry profile: they have a high proportion of a component most enriched in Mesolithic Caucasus hunter-gatherers and Neolithic Iranians and frequently harbour another component enriched in present-day South Asians (Supplementary Fig. 4). Based on the PCA and ADMIXTURE results, we heuristically assigned inner Eurasians to three clines: the ‘forest-tundra’ cline includes Russians and all Uralic and Yeniseian speakers; the ‘steppe-forest’ cline includes Turkic- and Mongolic-speaking populations from the Volga and Altai–Sayan regions and Southern Siberia; and the ‘southern steppe’ cline includes the rest of the populations.

eurasian-clines-uralic-altaic
The first two PCs summarizing the genetic structure within 2,077 Eurasian individuals. The two PCs generally mirror geography. PC1 separates western and eastern Eurasian populations, with many inner Eurasians in the middle. PC2 separates eastern Eurasians along the northsouth cline and also separates Europeans from West Asians. Ancient individuals (color-filled shapes), including two Botai individuals, are projected onto PCs calculated from present-day individuals.

For the forest-tundra populations, the Nganasan + Srubnaya model is adequate only for the two Volga region populations, Udmurts and Besermyans (Fig. 5 and Supplementary Table 8).

For the other populations west of the Urals, six from the northeastern corner of Europe are modelled with additional Mesolithic Western European hunter-gatherer (WHG) contribution (8.2–11.4%; Supplementary Table 8), while the rest need both WHG and early Neolithic European farmers (LBK_EN; Supplementary Table 2). Nganasan-related ancestry substantially contributes to their gene pools and cannot be removed from the model without a significant decrease in the model fit (4.1–29.0% contribution; χ2 P ≤ 1.68 × 10−5; Supplementary Table 8).

west-urals-finno-ugrians-qpadm
Supplementary Table 8. QpAdm-based admixture modeling of the forest-tundra cline populations. For the 13 populations west of the Urals, we present a four-way admixture model, Nganasan+Srubnaya+WHG+LBK_EN, or its minimal adequate subset. Modified from the article, to include colors for cultures, and underlined best models for Corded Ware ancestry among Uralians.

NOTE. It doesn’t seem like Hungarians can be easily modelled with Nganasan ancestry, though…

For the 4 populations east of the Urals (Enets, Selkups, Kets and Mansi), for which the above models are not adequate, Nganasan + Srubnaya + AG3 provides a good fit (χ2 P ≥ 0.018; Fig. 5 and Supplementary Table 8). Using early Bronze Age populations from the Baikal Lake region (‘Baikal_EBA’; Supplementary Table 2) as a reference instead of Nganasan, the two-way model of Baikal_EBA + Srubnaya provides a reasonable fit (χ2 P ≥ 0.016; Supplementary Table 8) and the three-way model of Baikal_EBA + Srubnaya + AG3 is adequate but with negative AG3 contribution for Enets and Mansi (χ2 P ≥ 0.460; Supplementary Table 8).

east-urals-ugric-samoyedic-qpadm
Supplementary Table 8. QpAdm-based admixture modeling of the forest-tundra cline populations. For the four populations east of the Urals, we present three admixture models: Baikal_EBA+Srubnaya, Baikal_EBA+Srubnaya+AG3 and Nganasan+Srubnaya+AG3. For each model, we present qpAdm p-value, admixture coefficient estimates and associated 5 cM jackknife standard errors (estimate ± SE). Modified from the article, to include colors for cultures, and underlined best models for Corded Ware ancestry among Uralians.

Bronze/Iron Age populations from Southern Siberia also show a similar ancestry composition with high ANE affinity (Supplementary Table 9). The additional ANE contribution beyond the Nganasan + Srubnaya model suggests a legacy from ANE-ancestry-rich clines before the Late Bronze Age.

bronze-age-iron-age-karasuk-mezhovska-tagar-qpadm
Supplementary Table 9. QpAdm-based admixture modeling of Bronze and Iron Age populations of southern Siberia. For ancieint individuals associated with Karasuk and Tagar cultures, Nganasan+Srubnaya model is insufficient. For all five groups, adding AG3 as the third ancestry or substituting Nganasan with Baikal_EBA with higher ANE affinity provides an adequate model. For each model, we present qpAdm p-value, admixture coefficient estimates and associated 5 cM jackknife standard errors (estimate ± SE). Models with p-value ≥ 0.05 are highlighted in bold face. Modified from the article, to include colors for cultures, and underlined best models for Corded Ware ancestry among Uralians.

Lara M. Cassidy comments the results of the study in A steppe in the right direction (you can read it here):

Even among the earliest available inner Eurasian genomes, east–west connectivity is evident. These, too, form a longitudinal cline, characterized by the easterly increase of a distinct ancestry, labelled Ancient North Eurasian (ANE), lowest in western European hunter-gatherers (WHG) and highest in Palaeolithic Siberians from the Baikal region. Flow-through from this ANE cline is seen in steppe populations until at least the Bronze Age, including the world’s earliest known horse herders — the Botai. However, this is eroded over time by migration from west and east, following agricultural adoption on the continental peripheries (Fig. 1b,c).

Strikingly, Jeong et al. model the modern upper steppe cline as a simple two-way mixture between western Late Bronze Age herders and Northeast Asians (Fig. 1c), with no detectable residue from the older ANE cline. They propose modern steppe peoples were established mainly through migrations post-dating the Bronze Age, a sequence for which has been recently outlined using ancient genomes. In contrast, they confirm a substantial ANE legacy in modern Siberians of the northernmost cline, a pattern mirrored in excesses of WHG ancestry west of the Urals (Fig. 1b). This marks the inhospitable biome as a reservoir for older lineages, an indication that longstanding barriers to latitudinal movement may indeed be at work, reducing the penetrance of gene flows further south along the steppe.

eurasian-clines-uralic-turkic-mongol-altaic
The genomic formation of inner Eurasians. b–d, Depiction of the three main clines of ancestry identified among Inner Eurasians. Sources of admixture for each cline are represented using proxy ancient populations, both sampled and hypothesised, based on the study’s modelling results. The major eastern and western ancestries used to model each cline are shown in bold; the peripheral admixtures that gave rise to these are also shown. Additional contributions to subsections of each cline are marked with dashed lines. b, The northernmost cline, illustrating the legacy of WHG and ANE-related populations. c,d, The upper (c) and lower (d) steppe clines are shown, both of which have substantial eastern contributions related to modern Tungusic speakers. The authors propose these populations are themselves the result of an admixture between groups related to the Nganasan, whose ancestors potentially occupied a wider range, and hunter-gatherers (HGs) from the Amur River Basin. While the upper steppe cline in c can be described as a mixture between this eastern ancestry and western steppe herders, the current model for the southern steppe cline as shown in d is not adequate and is likely confounded by interactions with diverse bordering ancestries. Credit: Ecoregions 2017, Resolve https://ecoregions2017.appspot.com/

Given the findings as reported in the paper, I think it should be much easier to describe different subclines in the “northernmost cline” than in the much more recent “Turkic/Mongolic cline”, which is nevertheless subdivided in this paper in two clines. As an example, there are at least two obvious clines with “Nganasan-related meta-populations” among Uralians, which converge in a common Steppe MLBA (i.e. Corded Ware) ancestry – one with Palaeo-Laplandic peoples, and another one with different Palaeo-Siberian populations:

siberian-clines-uralic-altaic
PCA of ancient and modern Eurasian samples. Ancient Palaeo-Laplandic, Palaeosiberian, and Altai clines drawn, with modern populations labelled. See a version with higher resolution.

The inclusion of certain Eurasian groups (or lack thereof) in the PCA doesn’t help to distinguish these subclines visually, and I guess the tiny “Naganasan-related” ancestral components found in some western populations (e.g. the famous ~5% among Estonians) probably don’t lend themselves easily to further subdivisions. Notice, nevertheless, the different components of the Eastern Eurasian source populations among Finno-Ugrians:

uralic-admixture-qpadm
Characterization of the Western and Eastern Eurasian source ancestries in inner Eurasian populations. [Modified from the paper, includes only Uralic populations]. a, Admixture f3 values are compared for different Eastern Eurasian (Mixe, Nganasan and Ulchi; green) and Western Eurasian references (Srubnaya and Chalcolithic Iranians (Iran_ChL); red). For each target group, darker shades mark more negative f3 values. b, Weights of donor populations in two sources characterizing the main admixture signal (date 1 and PC1) in the GLOBETROTTER analysis. We merged 167 donor populations into 12 groups (top right). Target populations were split into five groups (from top to bottom): Aleuts; the forest-tundra cline populations; the steppe-forest cline populations; the southern steppe cline populations; and ‘others’.

Also remarkable is the lack of comparison of Uralic populations with other neighbouring ones, since the described Uralic-like ancestry of Russians was already known, and is most likely due to the recent acculturation of Uralic-speaking peoples in the cradle of Russians, right before their eastward expansions.

west-eurasian-east-eurasian-ancestry
Supplementary Fig. 4. ADMIXTURE results qualitatively support PCA-based grouping of inner Eurasians into three clines. (A) Most southern steppe cline populations derive a higher proportion of their total Western Eurasian ancestry from a source related to Caucasus, Iran and South Asian populations. (B) Turkic- and Mongolic-speaking populations tend to derive their Eastern Eurasian ancestry more from the Devil’s Gate related one than from Nganasan-related one, while the opposite is true for Uralic- and Yeiseian-speakers. To estimate overall western Eurasian ancestry proportion, we sum up four components in our ADMIXTURE results (K=14), which are the dominant components in Neolithic Anatolians (“Anatolia_N”), Mesolithic western European hunter-gatherers (“WHG”), early Holocene Caucasus hunter-gatherers (“CHG”) and Mala from southern India, respectively. The “West / South Asian ancestry” is a fraction of it, calculated by summing up the last two components. To estimate overall Eastern Eurasian ancestry proportion, we sum up six components, most prevalent in Surui, Chipewyan, Itelmen, Nganasan, Atayal and early Neolithic Russian Far East individuals (“Devil’s Gate”). Eurasians into three clines. (A) Most southern steppe cline populations derive a higher proportion of their total Western Eurasian ancestry from a source related to Caucasus, Iran and South Asian populations. (B) Turkic- and Mongolic-speaking populations tend to derive their Eastern Eurasian ancestry more from the Devil’s Gate related one than from Nganasan-related one, while the opposite is true for Uralic- and Yeiseian-speakers. To estimate overall western Eurasian ancestry proportion, we sum up four components in our ADMIXTURE results (K=14), which are the dominant components in Neolithic Anatolians (“Anatolia_N”), Mesolithic western European hunter-gatherers (“WHG”), early Holocene Caucasus hunter-gatherers (“CHG”) and Mala from southern India, respectively. The “West / South Asian ancestry” is a fraction of it, calculated by summing up the last two components. To estimate overall Eastern Eurasian ancestry proportion, we sum up six components, most prevalent in Surui, Chipewyan, Itelmen, Nganasan, Atayal and early Neolithic Russian Far East individuals (“Devil’s Gate”).

A comparison of Estonians and Finns with Balts, Scandinavians, and Eastern Europeans would have been more informative for the division of the different so-called “Nganasan-like meta-populations”, and to ascertain which one of these ancestral peoples along the ancient WHG:ANE cline could actually be connected (if at all) to the Cis-Urals.

Because, after all, based on linguistics and archaeology, geneticists are not supposed to be looking for populations from the North Asian Arctic region, for “Siberian ancestry”, or for haplogroup N1c – despite previous works by their peers – , but for the Bronze Age Volga-Kama region…

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Sintashta diet and economy based on domesticated animal products and wild resources

indo-iranian-sintashta-uralic-migrations

New paper (behind paywall) Bronze Age diet and economy: New stable isotope data from the Central Eurasian steppes (2100-1700 BC), by Hanks et al. J. Arch. Sci (2018) 97:14-25.

Interesting excerpts (emphasis mine):

Previous research at KA-5 was carried out by A. V. Epimakhov in 1994–1995 and 2002–2003 and resulted in the excavation of three Sintashta culture barrows (kurgans) that produced 35 burial pits and a reported 100 skeletons (Epimakhov, 2002, 2005; Epimakhov et al., 2005; Razhev and Epimakhov, 2004). Seven AMS radiocarbon dates on human remains from the cemetery yielded a date range of 2040–1730 cal. BC (2 sigma), which placed the cemetery within the Sintashta phase of the regional Bronze Age (Hanks et al., 2007). Twelve recently obtained AMS radiocarbon dates, taken from short-lived wood and charcoal species recovered from the Kamennyi Ambar settlement, have provided a date range of 2050–1760 cal. BC (2 sigma). Importantly, these dates confirm the close chronological relationship between the settlement and cemetery for the Middle Bronze Age phase and discount the possibility of a freshwater reservoir effect influencing the earlier dating of the human remains from the Kamennyi Ambar 5 cemetery (Epimakhov and Krause, 2013).

Sintashta cemeteries frequently yield fewer than six barrow complexes and the number of skeletons recovered represents a fraction of the total population that would have inhabited the settlements (Judd et al., 2018; Johnson and Hanks, 2012). Scholars have suggested that only members of higher status were afforded interment in these cemeteries and that principles of social organization structured placement of individuals within central or peripheral grave pits (Fig. 2) (Koryakova and Epimakhov, 2007: 75–81). In comparison with other Sintashta cemeteries that have been excavated, KA-5 provides one of the largest skeletal inventories currently available for study.

kamenniy-ambar
Upper – plan of Kamennyi Ambar settlement and cemetery; Lower – plan views of Kurgan 2 and Kurgan 4 from KA-5 Cemetery (kurgan plans redrawn from Epimakhov, 2005: 10, 79).

The KA-5 (MBA), Bestamak (MBA) and Lisakovsk (LBA) datasets exhibited a wide range of δ13C and δ15N values for both humans and herbivores (Figs. 5 and 6 & Table 8). This diversity in isotopic signals may be evident for a variety of reasons. For example, the range of values may be associated with a broad spectrum of C3 and C4 plant diversity in the ancient site biome or herbivore grazing patterns that included more diverse environmental niche areas in the microregion around the sampled sites. Herders also may have chosen to graze animals in niche areas due to recognized territorial boundaries between settlements and concomitant patterns of mobility. Importantly, data from Bolshekaragansky represents humans with lower δ15N values that are more closely associated with δ15N values of the sampled domestic herbivores (Fig. 6). When the archaeological evidence from associated settlement sites is considered, Bolshekaragansky, Bestamak, Lisakovsk and KA-5 have been assumed to represent populations that shared similar forms of pastoral subsistence economies with significant dietary reliance upon domesticated herbivore meat and milk. Human diets have δ13C values closely related to those of local herbivores in terms of the slope of the trendline and range of values (Fig. 6). Comparatively, the cemetery of Bolshekaragansky (associated with the Arkaim settlement) reflects individuals with trend lines closer to those of cattle and caprines and may indicate a stronger reliance on subsistence products from these species with less use of wild riverine and terrestrial resources. The site of Čiča is significantly different with elevated human δ15N isotopic values and depleted δ13C values indicative of a subsistence regime more closely associated with the consumption of freshwater resources, such as fish. The stable isotopic data in this instance is strongly supported by zooarchaeological evidence recovered from the Čiča settlement and also is indicative of significant diachronic changes from the LBA phases through the Iron Age (Fig. 6).

kamenniy-ambar-isotopic-chicha-lisakovsk-bestamark
Regional analysis and comparison of stable isotope results from humans (adults) and animals recovered from MBA and LBA cemeteries in the Southern Urals (Kamennyi Ambar 5 & Bolshekaragansky) northwestern Kazakhstan (Liskovsk & Bestamak) and southwestern Siberia (Čiča).

Conclusion

(…) The isotopic results from KA-5, and recent botanical and archaeological studies from the Kamennyi Ambar settlement, have not produced any evidence for the production or use of domesticated cereals. While this does not definitively answer the question as to whether Sintashta populations engaged in agriculture and/or utilized agricultural products, it does call into serious question the ubiquity of such practices across the region and correlates well with recent archaeological, bioarchaeological, and isotopic studies of human and animal remains from the Southwestern Urals region and Samara Basin (Anthony et al., 2016; Schulting and Richards, 2016). The results substantiate a broader spectrum subsistence diet that in addition to the use of domesticated animal products also incorporated wild flora, wild fauna and fish species. These findings further demonstrate the need to draw on multiple methods and datasets for the reconstruction of late prehistoric subsistence economies in the Eurasian steppes. When possible, this should include datasets from both settlements and associated cemeteries.

Variability in subsistence practices in the central steppes region has been highlighted by other scholars and appears to be strongly correlated with local environmental conditions and adaptations. More comprehensive isotopic studies of human, animal and fish remains are of fundamental importance to achieve more robust and empirically substantiated reconstructions of local biomes and to aid the refinement of regional and micro-regional economic subsistence models. This will allow for a fuller understanding of key diachronic shifts within dietary trends and highlight regional variation of such practices. Ultimately, this will more effectively index the diverse social and environmental variables that contributed to late prehistoric lifeways and the economic strategies employed by these early steppe communities.

Social organization of Sintashta-Petrovka

Interesting to remember now the recent article by Chechushkov et al. (2018) about the social stratificaton in Sintashta-Petrovka, and how it must have caused the long-lasting, peaceful admixture process that led to the known almost full replacement of R1b-L23 (mostly R1b-Z2103) by R1a-Z645 (mostly R1a-Z93) subclades in the North Caspian steppe, coinciding with the formation of the Proto-Indo-Iranian community and language (read my thoughts on this after Damgaard et al. 2018).

Here is another relevant excerpt from Chechushkov et al. (2018), translated from Russian:

settlement-kamenniy-ambar
The map of the settlement of Kamennyi Ambar with excavations, soil cores, and test pits. Legend: a — cuts of the sides of ravines; b — test pits of 2015—2017; c — test pits of 2004; d — soil-science samples with a cultural layer; e — soil-science samples without cultural layer; f — borders of archaeological sites (interpretation of the plan of magnetic anomalies); g — boundaries of excavated structures (1, 2, 4, 5, 7 — Sintashta-Petrovka culture; 3, 6 — Srubnaya-Alakul’ culture).

The analysis suggests that the Sintashta-Petrovka societies had a certain degree of social stratification, expressed both in selective funeral rituals and in the significant difference in lifestyle between the elite and the immediate producers of the product. The data obtained during the field study suggest that the elite lived within the fortifications, while a part of the population was outside their borders, on seasonal sites, and also in stationary non-fortified settlements. Probably, traces of winter settlements can be found near the walls, while the search for summer ones is a task of a separate study. From our point of view, the elite of the early complex societies of the Bronze Age of the Eurasian steppe originated as a response to environmental challenges that created risks for cattle farming. The need to adapt the team to the harsh and changing climatic conditions created a precedent in which the settled collectives of pastoralists – hunter-gatherers could afford the content and magnificent posthumous celebration of people and their families who were not engaged in the production or extraction of an immediate product. In turn, representatives of this social group directed their efforts to the adoption of socially significant decisions, the organization of collective labor in the construction of settlement-shelters and risked their lives, acting as military leaders and fighters.

Thus, in Bronze Age steppe societies, the formation, development and decline of social complexity are directly related to the intensity of pastoralism and the development of new territories, where collectives had to survive in part a new ecological niche. At the same time, some members of the collective took upon themselves the organization of the collective’s life, receiving in return a privileged status. As soon as the conditions of the environment and management changed, the need for such functions was virtually eliminated, as a result of which the privileged members of society dissolved into the general mass, having lost their lifetime status and the right to be allocated posthumously.

Also interesting for the MLBA haplogroup bottleneck in the region is the paper by Judd et al. (2017) about fast life history in Early Indo-Iranian territories.

On the arrival of haplogroup N1c1-L392

Regarding the special position of the Chicha-1 samples in the change of diet and economy during the Iron Age, it is by now well known that haplogroup N must have arrived quite late to North-East Europe, and possibly not linked with the expansion of Siberian ancestry – or linked only with some waves of Siberian ancestry in the region, but not all of them. See Lamnidis et al. (2018) for more on this.

Also, the high prevalence of haplogroup N among Fennic and Siberian (Samoyedic) peoples is not related: while the latter reflects probably the native (Palaeo-Siberian) population that acquired their Uralic branch during the MLBA expansions associated with Corded Ware groups, the former points to the expansion of Fennic peoples into Saamic territory (i.e. after the Fenno-Saamic split) as the most likely period of expansion of N1c1-L392 subclades (see known recent bottlenecks among Finns, and on Proto-Finnic dialectalization).

Probably related to these late incomers are the ancient DNA samples from the Sargat culture during the Iron Age, which show the arrival of N subclades in the region, replacing most – but not all – R1a lineages (see Pilipenko et al. (2017)). Regarding the site of Chicha-1, the following are relevant excerpts about the cultural situation that could have allowed for such stepped, diachronic admixture events in Northern Eurasia, from the paper Stages in the settlement history of Chicha-1: The Results of ceramic analysis, by Molodin et al. (2008):

The stratigraphic data allows us to make the following inference: originally, the settlement was inhabited by people bearing the Late Irmen culture. Later, the people of the Baraba trend of the Suzgun culture arrived at the site (Molodin, Chemyakina, 1984: 40–62). The Baraba-Suzgun pottery demonstrates features similar to what has been reported from the sites of the transitional Bronze to Iron Age culture in the pre-taiga and taiga zones in the Irtysh basin (Potemkina, Korochkova, Stefanov, 1995; Polevodov, 2003). The major morphological types are slightly and well-profiled pots with a short throat. (…)

chicha-irmen-tagar-baraba-forest-siberian
Map showing the location of Chicha-1.

During the following stage of development of the site, the Chicha population increased with people who practiced cultures others than those noted in earlier collections. The ceramic materials from layer 5 provide data on possible relationships. In addition to migrants from northwestern regions practicing the Suzgun culture, there were people bearing the Krasnoozerka culture. Available data also suggests that people from the northern taiga region with the Atlym culture visited the site.

However, people from the west and southwest represent the greatest migration to the region under study. In all likelihood they moved from the northern forest-steppe zone of modern Kazakhstan and practiced the Berlik culture. The spatial distribution analysis of the Chicha-1 site suggests that the Berlik population was rather large. The Berlik people formed a single settlement with the indigenous Late Irmen people and apparently waged certain common economic activities, but preserved their own ethnic and cultural specificity (Molodin, Parzinger, 2006: 49–55). Judging by the data on the chronological sequence of deposited artifacts, migration took place roughly synchronously, hence Chicha-1 became a real cultural and economic center.

(…) In sum, the noted distribution of ceramics over the culture-bearing horizons suggests that beginning with layer 5, traditions of ceramic manufacture described above were practiced, hence the relevant population inhabited the site. Apparently, there were two predominant traditions: the local Late Irmen cultural tradition and the Berlik tradition, which was brought by the immigrants. The Late Irmen people mostly populated the citadel, while the Berlik immigrants inhabited the areas to the east and the north of the citadel.

The stratigraphic data also suggest that the Early Sargat ceramics emerged at the site likely as a part of the Late Irmen tradition (…) Early Sargat ceramics is apparently linked with the Late Irmen tradition. Artifacts associated with the Sargat culture proper have been found in several areas of Chicha-1 (e.g., in excavation area 16). However, the Sargat people appeared at the site after it had been abandoned by its previous inhabitants, and had eventually become completely desolated. This happened no earlier than the 6th cent. BC, possibly in the 5th cent. BC (in fact, the radiocarbon dates for that horizon are close to the turn of the Christian era).

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