Proto-Tocharians: From Afanasievo to the Tarim Basin through the Tian Shan

tocharians-early-eneolithic

A reader commented recently that there is little information about Indo-Europeans from Central and East Asia in this blog. Regardless of the scarce archaeological data compared to European prehistory, I think it is premature to write anything detailed about population movements of Indo-Iranians in Asia, especially now that we are awaiting the updates of Narasimhan et al (2018).

Furthermore, there was little hope that Tocharians would be different than neighbouring Andronovo-like populations (see a recent post on my predicted varied admixture of Common Tocharians), so the history of both unrelated Late PIE languages would have had to be explained by the admixture of Afanasievo-related groups with peoples of Andronovo descent and their acculturation.

However, data reported recently by Ning, Wang et al. Current Biology (2019) confirmed that peoples of mainly Afanasievo ancestry – as opposed to those of Corded Ware-related ancestry expanding with the Srubna-Andronovo horizon – spread the Tocharian branch of Proto-Indo-European from the Altai into the Tian Shan area, surviving essentially unadmixed into the Early Iron Age.

This genetic continuity of Tocharians will no doubt help us disentangle a great part the ethnolinguistic history of speakers of the Tocharian branch of Proto-Indo-European, from Pre-Proto-Tocharians of Afanasievo to Common Tocharians of the Late Bronze Age/Iron Age eastern Tian Shan.

NOTE. Tocharian’s isolation from the rest of Late PIE dialects and its early and intense language contacts have always been the key to support an early migration and physical separation of the group, hence the traditional association with Afanasievo, a late Repin/early Yamna offshoot. Even with the current incomplete archaeological and genetic picture, there is no other option left for the expansion of Tocharian.

It is not possible to use the currently available ancestry data to map the evolution of Afanasievo ancestry, lacking a proper geographical and temporal transect of Central and East Asian groups. In spite of this, Ning, Wang, et al. (2019) is a huge leap forward, discarding some archaeological models, and leaving only a few potential routes by which Tocharians may have spread southward from the Altai.

NOTE. I have updated the maps of prehistoric cultures accordingly, with colours – as always – reflecting the language/ancestry evolution of the different groups, even though the archaeological data of some groups of Xinjiang remains scarce, so their ethnolinguistic attribution – and the colours picked for them – remain tentative.

xinjiang-andronovo-xiaohe-horizon-bronze-iron-age
A rough timeline of related archaeological sites from North Eurasia. Image modified from Yang (2019).

Tocharians

The recent book Ancient China and its Eurasian Neighbors. Artifacts, Identity and Death in the Frontier, 3000–700 BCE, by Linduff, Sun, Cao, and Liu, Cambridge University Press (2017) offers an interesting summary of the introduction of metalworking into western China.

Here are some relevant excerpts (emphasis mine):

Although [the Xinjiang] route is not uniformly agreed upon (Shelach-Lavi 2009: 134–46), this western transmission has been thought to have passed through eastern Kazakhstan, especially as it is manifest in Semireiche, with Yamnaya, Afanasievo (copper) and Andronovo (tin bronze) peoples (Mei 2000: Fig. 3). From Xinjiang this knowledge has been thought to have traveled through the Gansu Corridor via the Qijia peoples (Bagley 1999) and then into territories controlled by dynastic China. The dating of this process is still a problem, as the sites and their contents in Xinjiang are consistently later than those in Gansu, suggesting that the point of contact was in Gansu and that the knowledge then spread from there westward.

1. Eneolithic Altai

tocharians-chalcolithic-eneolithic
Afanasievo expansion ca. 3300-2600 BC. See full culture and ancient DNA maps.

The Afanasievo sites, as they are identified in Mongolia, for instance, make up an Eneolithic culture analogous to that of southern Siberia (3100/2500–2000 BCE) in the Upper Yenissei Valley that is characterized by copper tools and an economy reliant on horse, sheep and cattle breeding as well as hunting. (…) The Afanasievo is best known through study of its burials, which typically include groups of round barrows (kurgans), each up to 12 m in diameter with a stone kerb and covering a central pit grave containing multiple inhumations. In their Siberian context, burial pottery types and styles have suggested contacts with the slightly earlier Kelteminar culture of the Aral and Caspian Sea area.

The Afanasievo culture monuments, located in the northern Altai and in the Minusinsk Basin (the western Sayan), have been seen as analogous evidence for cross-Eurasian exchange. These complexes contain small collections of metal, and many of the items are made of brass, although golden, silver and iron ornaments were also identified. A mere one-fourth of these objects are tools and ornaments, while the rest consist of unshaped remains and semi-manufactured objects. Its metallurgical tradition has recently been dated by Chernykh to as early as 3100 to 2700 BCE (1992),making it more compatible chronologically with the early brass-using sites in Shaanxi mentioned above. Kovalev and Erdenebaatar have excavated barrows in Bayan-Ulgii, Mongolia, that have been carbon-dated to the first half of the third millennium BCE and associated by ceramic types and styles and burial patterns with the Afanasievo (Kovalev and Erdenebaatar 2009: 357–58). These mounded kurgans were covered with stone and housed rectangular, wooden-faced tombs that included Afanasievo-type bronze awls, plates and small “leaf-shaped” knife blades (Kovalev and Erdenebaatar 2009: Figs. 6 and 7).

They also excavated sites belonging to the more recently identified Chemurchek archaeological culture, located in the foothills of the Mongolian Altai (Kovalev 2014, 2015) (Fig. 2.6). These sites are carbon-dated to the same period as the Afanasievo burials or to c. 3100/2500–1800 BCE (six barrows in Khovd aimag and four in Bayan-Ulgo aimag). In the rectangular stone kerbed Chemurchek slab burials (Ulaaanhus sum, Bayan-ul’gi aimag and so forth), bronze items included awls; and at Khovd aimag, Bulgan sum, in addition to stone sculptures, three lead and one bronze ring were excavated (Kovalev and Erdenebaatar 2009: Figs. 2 and 3; Fig. 2.6). Although we will not know if they were produced locally until much further investigation is undertaken, these discoveries do document knowledge of various uses and types of metal objects in western and south central Mongolia. The types of metal items thus far recovered are simple tools (awls) and rings (ornamental?) not unlike those associated with Andronovo archaeological cultures as well.

This is a complex circumstance where archaeological evidence is not complete, but raises very important questions about transmission of metallurgical knowledge to and from areas in present-day China. In the 1970s some Afanasievo mounds were excavated in Central Mongolia by a Soviet–Mongolian expedition led by V. V. Volkov and E. A. Novgorodova (Novgorodova 1989: 81–85). Unfortunately, these mounds did not yield metal objects, only ceramics, but they show that the Afanasievo culture with the Eneolithic metallurgical tradition of manufacturing pure copper items had already moved east at least far as central Mongolia. In 2004, Kovalev and Erdenebaatar investigated a large Afanasievo mound, Kulala ula, in the extreme northwest of Mongolia, near the Russian border (Kovalev and Erdenebaatar 2009). There they found a copper knife and awl (Fig. 2.5). There are five C14 dates on wood, coal and human bones from this mound, which belong to the period 2890–2570 BCE. This shows that the Afanasievo culture were carriers of technology and produced artifacts in the first half of the third millennium BCE and that they also moved south along the foothills of the Mongolian Altai. Afanasievo culture in Altai and the Minusinsk basin is dated by C14 to 3600–2500 BCE (Svyatko et al. 2009; Polyakov 2010). In the north of Xinjiang in the Altai district, several typical egg-shaped vessels and two censers of Afanasievo types were found. Some of these have been obtained from the stone boxes (chambers of megalithic graves of the Chemurchek culture) (Kovalev 2011). Thus, the Afanasievo tradition of pure copper metallurgy must have spread to the northern foothills of the Tienshan Mountains no later than the mid-third millennium BCE. The links with Afanasievo and local cultures adjacent to and south of the mountains into present-day China can now be assumed.

tocharians-chalcolithic-late
Afanasievo – Chemurchek evolution ca. 2600-2200 BC. See full culture and ancient DNA maps.

2. Bronze Age Altai

Kovalev and Erdenebaatar (2014a) and later Tishkin, Grushin, Kovalev and Munkhbayar (2015) in Western Mongolia conducted large-scale excavations of megalithic barrows of the Chemurchek culture (dated about 2600–1800 BCE). This peculiar culture appeared in Dzungaria and the Mongolian Altai in the second quarter of the third millennium BCE and for some time existed together with the late Afanasievo culture, as evidenced by the findings of Afanasievo ceramics in Chemurchek graves, in the stone boxes. Unfortunately, in China we do not yet know of any metal object related,without doubt, to the Chemurchek culture. Kovalev, Erdenebaatar, Tishkin and Grushin found several leaden ear rings and one ring of tin bronze in three excavated Chemurchek stone boxes (Kovalev and Erdenebaatar 2014a; Tishkin et al. 2015). Such lead rings are typical for Elunino culture,which occupied the entire West Altai after 2400–2300 BCE (Tishkin et al. 2015). This culture had developed a tradition of bronze metallurgy with various dopants, primarily tin. Thus, the tradition of bronze metallurgy as early as this time could have penetrated the Mongolian Altai far to the south. In addition, in the Hadat ovoo Chemurchek stone box, Kovalev and Erdenebaatar discovered stone vessels refurbished with the help of copper “patches,” indicating the presence there of metallurgical production (Fig. 2.7) (Kovalev and Erdenebaatar 2014a). In one of the secondary

Chemurchek graves unearthed by Kovalev and Erdenebaatar in Bayan-Ulgi (2400–2220 BCE), a bronze awl was found (Kovalev and Erdenebaatar 2009). Kovalev and Erdenebaatar also discovered a new culture in the territory of Mongolia (Map 2.3), one that begins immediately after Chemurchek – Munkh-Khairkhan culture (Kovalev and Erdenebaatar 2009, 2014b). To date, about 17 mounds of this culture have been excavated in Khovd, Zavkhan, Khovsgol, Bulgan aimag of Mongolia. This culture dates from about 1800 to 1500 BCE, that is, contemporary with the Andronovo culture. Therefore, the Andronovo culture does not extend far into the territory of Mongolia. Three knives without dedicated handles or stems and five awls have been found in the Munkh-Khairkhan culture mounds (Fig. 2.8). All these products are made of tin bronze. (…) Additionally, eight Late Bronze Age burials (c. 1400–1100 BCE) were unearthed in the Bulgan sum of Khovd aimag and belong to another previously unknown culture called Baitag. And in the Gobi Altai, a new group of “Tevsh” sites dating to the Late Bronze Age were defined in Bayankhongor and South Gobi aimags (Miyamoto and Obata 2016: 42–50). From these Tevsh and Baitag sites, we see the expansion of burial goods to include beads of semiprecious stones (carnelian), bronze beads, buttons and rings and even the famous elaborate golden hair ornaments (Tevsh uul;Bogd sum;Uverkhanagia aimag) from the Baitag barrows (Kovalev and Erdenebaatar 2009: Fig. 5; Miyamoto and Obata 2016).

2.1. Chemurchek

About the Chemurchek culture, from A re-analysis of the Qiemu’erqieke (Shamirshak) cemeteries, Xinjiang, China, by Jia and Betts JIES (2010) 38(4):

The major characteristics of Qiemu’erqieke Phase I include:

  1. Burials with two orientations of approximately 20° or 345°.
  2. Rectangular enclosures built using large stone slabs. The size of the enclosure varies from a maximum of 28 x 30 m.*to a minimum of 10.5 x 4.4 m. (Figure 8, Table 2).
  3. *The stone enclosure located near Hayinar is the largest one at approximately 30 x 40 m. based on pacing of the site during a visit by the authors in 2008.

  4. Almost life-sized anthropomorphic stone stelae erected along one side of the stone enclosures (Lin Yun 2008).
  5. Single enclosures tend to contain one or more than one burial, all or some with stone cist coffins.
  6. The cist coffin is usually constructed using five large stone slabs, four for the sides and one on top, leaving bare earth at the base (Zhang Yuzhong 2007). Sometimes the insides of the slabs have simple painted designs (Zhang Yuzhong 2005).
  7. Primary and secondary burials occur in the same grave.
  8. Some decapitated bodies (up to 20) may be associated with the main burial in one cist.
  9. Bodies are commonly placed on the back or side with the legs drawn up.
  10. Grave goods include stone and bronze arrowheads, handmade gray or brown round-bottomed ovoid jars, and small numbers of flat-bottomed jars (Fig. 7).
  11. Clay lamps appear to occur together with roundbottomed jars.
  12. Complex incised decoration on ceramics is common but some vessels are undecorated.
  13. The stone vessels are distinctive for the high quality of manufacture.
  14. Stone moulds indicate relatively sophisticated metallurgical expertise.
  15. Artefacts made from pure copper occur.
  16. Sheep knucklebones (astragali) imply a tradition (as in historical and modern times) of keeping knucklebones for ritual or other purposes. They also indicate the herding of domestic sheep as part of the subsistence economy.
tocharians-bronze-age-early
Chemurchek culture ca. 2200-1750 BC. See full culture and ancient DNA maps.

Chemurchek dating

Available evidence suggests that the date range for Qiemu’erqieke Phase I should fall from the later third into the early second millennium BC. There are several reasons to suggest that the time span is around the early second millennium BC. Lin Yun (2008) (…) maintains that the bronze artefacts found in Phase I show a greater sophistication in the level of copper alloy technology than that of the pure copper artefacts common to the Afanasievo tradition. On this basis it might be suggested that the Afanasievo could be considered to be Chalcolithic with a time span across much of the third millennium BC ( Gorsdorf et al. 2004: 86, Fig. 1). Qiemu’erqieke Phase I, however, should more properly be considered as Bronze Age.

Lin Yun also used the bronze arrowhead from burial Ml 7 to narrow down the date of Qiemu’erqieke Phase I. Two arrowheads were found in this burial, one of them leaf shaped with a single barb on the back (Fig. 7:4). A similar arrowhead, together with its casting mould, has been found at the Huoshaogou site of Siba tradition (Li Shuicheng 2005, Sun Shuyun and Han Rufen 1997), in Gansu province, northwest China, dated around 2000-1800 BC (Li Shuicheng and Shui Tao 2000) . This supports a date in the early second millennium BC for the Qiemu’erqieke arrowhead. The painted, round-bottomed jar from the Tianshanbeilu cemetery Qia Weiming, Betts and Wu Xinhua 2008: Fig. 7, bottom left) has been considered as a hybrid between the Upper Yellow River Bronze Age cultures of Siba in northwest China and the steppe tradition of Qiemu’erqieke in west Siberia (Li Shuicheng 1999). If this assumption is correct, the date of Tianshanbeilu, around 2000 BC, can be used as a reference for Qiemu’erqieke Phase I (Jia Weiming, Betts and Wu Xinhua 2008, Lin Yun 2008, Li Shuicheng 1999). Stone arrowheads found in Qiemu’erqieke Phase I also imply that the date is likely to fall within the earlier part of the Bronze Age as no such stone arrowheads have yet been found elsewhere in sites of the Bronze Age in Xinlang dated after the beginning of the second millennium BC.*
*For example Chawuhu and Xiaohe cemeteries (Xinjiang Institute of Archaeology 1999, 2003).

pottery-afanasevo-chemurchek
Pottery of Afanasevo and East European traits from the Chemurchek complex. Image modified from Kovalev (2017).

(…) Pottery “oil burners” (goblet-like ceramic vessels, possibly lamps) have been found in three traditions: Afanasievo (Gryaznov and Krizhevskaya 1986:21), Okunevo and Qiemu’erqieke. It is believed that this oil-burner found in Siberia and the Altai is a heritage from the Yamnaya and Catacomb
cultures (Sulimirski 1970: 225, 425; Shishlina 2008:46) in the Caspian steppe further to the west, but does not seem to exist in known Andronovo cultures.
The oil-burner tends to disappear after around 2300 BC during the mid-Okunevo period. It is, however, possible that the tradition continues longer in the Qiemu’erqieke sites.

The construction of the stone enclosures also reveals a close connection between Qiemu’erqieke Phase I and the mid and late Okunevo tradition (Sokolova 2007). Slab built stone enclosures emerged in both the Okunevo and Afanasievo traditions (Gryaznov and Krizhevskaya 1986:15-23, Kovalev 2008, Sokolova 2007, Anthony 2007:310, Koryakova and Epimakhov 2007). In the early Afanasievo the enclosure is circular with no cist coffin (Anthony 2007:310, Gryaznov and Krizhevskaya 1986:20), but in the early stage of the Okunevo square stone enclosures with a single cist burial are dominant. Square or rectangular stone enclosures are a marked feature of Qiemu’erqieke Phase I, suggesting temporal relationships between Qiemu’erqieke Phase I and the Okunevo. In Okunevo chronological group II, possibly with influence from the Anfanasievo, circular stone enclosures appeared in combination with rectangular enclosures within individual cemeteries, referred to by Sokolova (2007: table 2) as hybrid examples. By Okunevo chronological group III, rectangular stone slab enclosures with multi-burials emerged again. This is the dominant form in Qiemu’erqieke Phase I. Okunevo burial traditions changed again to single cist burials in the late stage around chronological group V ( Sokol ova 2007). A specific mortuary rite of decapitated burials exists in both the Qiemu’erqieke and Okunevo traditions (Sokolova 2007, Chen Kwang-tzuu and Hiebert 1995), as does the occasional occurrence of painted designs on the interior of the slabs forming the cists ( e.g., Khavrin 1997: 70, fig. 4; 77: tab. IV.5). Based on these comparisons, the date of Qiemu’erqieke Phase I may well parallel that of the Okunevo from at least chronological group II around 2400 BC (Gorsdorf et al. 2004: fig. 1).

khuh-udzuur-barrow
Khuh Udzuuriin I-1 elite barrow (ca. 2470-2190 BC). Modified from Image modified from Kovalev (2014).

In addition to the pottery making tradition, the anthropomorphic stone stelae may also have earlier antecedents. In the Okunevo assemblage there are anthropomorphic stelae that are longer, thinner and more abstract than those of Qiemu’erqieke. There is no indication of such stelae in the Afanasievo tradition (Gryaznov and Krizhevskaya 1986:15-23). However, further to the west, anthropomorphic stone stelae are associated with the Kemi-Oba and Yamnya cultures around the third millennium BC (Telegin and Mallory 1994; Figure 13). Some major characteristics of these stelae such as the icons on the front face of the stelae (Telegin and Mallory 1994:8-9) also appear on stelae found in Qiemu’erqieke Phase I. Recalling the oil burners that may have been inherited from the Yamnya culture and which are found in the Afansievo, Okunevo and Qiemu’erqieke Phase I, it migh t be possible to speculate that Qiemu’erqieke Phase I has its origins even earlier than the first half of the third millennium BC. This idea has also been suggested by Kovalev ( 1999).

Despite the affinities with the Okunevo cultural tradition, Qiemu’erqieke Phase I appears to be a discrete regional variant. The ceramic assemblage shows traits unique to this cluster of sites, while the anthropomorphic stelae are also distinctive markers of this tradition.

khuh-udzuur-stela
Khuh Udzuur anthropomorphic stone stela, oriented toward the south – south-east. Image modified from Kovalev (2014).

3. Bronze Age Xinjiang

I recently reported on this blog the description of Xiaohe and Gumugou cemeteries from interesting Master’s thesis Shifting Memories: Burial Practices and Cultural Interaction in Bronze Age China: A study of the Xiaohe-Gumugou cemeteries in the Tarim Basin, by Yunyun Yang, Uppsala University, Department of Archaeology and Ancient History (2019).

It also offered a full summary of findings from prehistoric sites of Xinjiang related to the arrival of a cultural package from the Altai region, ultimately connected to Afanasievo. Relevant excerpts include the following (emphasis mine):

In Bronze Age Xinjiang, burials were diverse but also show some common features between different geographic sections. The main three mountains, including Kunlun Mountains, Tian Shan (mountains) and Altai Mountains, enclose the Tarim Basin, and the Dzungaria Basin, but leave the eastern part of the Tarim Basin and the south-eastern part of the Dzungaria Basin open (with easy access to the surroundings). The Hami Basin is located at the transitional area, connecting the two basins. Burials are mainly spread along the edge of the mountain ranges.

xinjiang-afanasievo-andronovo-bmac-tian-shan
An assumption of the spreading/expansion routes stone burial construct.

3.1. The Lop Nur region

In the Lop Nur region, the Xiaohe cemetery (2000-1450 BCE) and the Gumugou cemetery (1900-1800 BCE) had many common features shared, and so is the Keliyahe northern cemetery:

  • Cemeteries were located in sandy areas;
  • Rectangular/boat-shaped wooden coffins with monuments of wooden planks or poles;
  • Coffins had no bottoms;
  • The dead were placed lying straight on the back;
  • The dead were commonly buried in single graves.

The Gumugou cemetery contained six special sun-radiating-spokes burial pattern in addition to the normal burials, which were similar to the wooden coffin graves of the Xiaohe cemetery.

NOTE. For more on Xiaohe and Gumugou, see the recent post on Proto-Tocharians. See other papers on the Andronovo horizon for other Early to Middle Bronze Age cultural groups less clearly associated with the Xiaohe horizon, like Hazandu, Xintala, or the Chust culture.

From Shuicheng (2006):

An assemblage of early bronzes had been recovered from northwestern Xinjiang and the periphery of Dzungaria 准噶尔 Basin. It comprises a variety of utilitarian tools and weapons, and a small number of apparels. These artifacts bear the stamps of Andronovo Culture in form, artifact type and decorative pattern. The metallographic analysis on selected artifacts indicates that they comprise mainly of tin-bronzes that contain 2–10% of tin. Moreover, the chemical compositions of these artifacts are similar to that of the Andronovo Culture. Latter date (first half of the 1st millennium BC) artifacts of the assemblage include a small number of arsenic bronzes. In all, during the period between the mid-2nd and mid-1st millennium BC, copper and bronze artifacts coexisted in this region, albeit tin-bronze comprised the majority. The composition of alloy did not show significant change over time. Some colleagues pointed out that the Nulasai 奴拉赛 site at Nileke 尼勒克 County in the Yili 伊犁 River basin of Xinjiang was the pioneer in the use of “sulphuric ore–ice copper–copper”technology. It is also the only early smelting site in Euro-Asia that arsenic ore was added to deliberately produce an alloy

tocharians-bronze-age-middle
Prehistoric cultures of Xinjiang during the Middle Bronze Age. See full culture and ancient DNA maps.

3.2. The Hami Basin-the Balikun Grassland

From Yang (2019):

The Hami Basin-the Balikun Grassland area is located at the eastern part of Tian Shan. The area is divided in a northern basin and a southern basin by the east-west stretch of the Tian Shan. In the Hami Basin-the Balikun Grassland area, the main type of burials were earth-pit graves in the early Bronze Age, and burials of stone-pit with barrows became more common in the late Bronze Age. The Hami-Tianshan-Beilu cemetery is a representative of the earth-pit graves. The features of the Hami-Tianshan-Beilu cemetery (2000-1500 bce) here were:

  • Rectangular earth pit graves;
  • The dead were often in a hocker position lying on one side;
  • Commonly a single dead in one grave.
balikun-grassland
The Balikun grassland today (source).

The Hami-Wubu cemetery (earlier than 1000 bce) and the Yanbulake cemetery (1200-600 bce) are representatives of another common earth-pit graves. Common features here were:

  • Rectangular earth pits, with two storeys and/or roofed with wooden boards;
  • The dead was placed in a hocker position lying on one side;
  • Mostly a single dead in one grave.

Later there appeared more stone-pit graves in this area, and the features can be summarized as:

  • Round burial mounds, commonly constructed by stones or a mix of stones and earth;
  • Burial mounds with a sunken top or a normal (dome) top;
  • The diameter of the burial mounds varied between 3 and 25.4 m (but not necessarily limited in this scope);
  • Circular or rectangular stone kerbs;
  • Rectangular stone pits, constructed by earth, or stones, or a mix of earth and stones;
  • Rectangular stone pits contained wooden coffins (represented by the Yiwu Baiqi’er cemetery).
hami-basin-balikun-grassland-iron-age-burials
Some representatives of stone burials in the Hami Basin – the Balikun Grassland in the Iron Age (Adapted from: Xinjiang 2011, 29-41). Image modified from Yang (2019).

In the Hami Basin, the Bronze Age cemeteries show common burial features like earth pits and hocker position of the dead. With similar pottery styles in the Hami-Tianshan-Beilu cemetery to those in the Machang and Siba cultures (Xinjiang 2011: 17), it suggests possible cultural influence or people’s migrating from the Hexi Corridor in the east.

In the Balikun Grassland, burials in an earlier time contained mostly earth-pit graves but also a small number of stone-pit graves. The pebbles were imbedded in the floors and the walls of the graves in a rectangular shape, e.g. the Balikun-Nanwan cemetery (1600-1000 bce). In a later time, there appeared huge burial mounds with a sunken top, and with the diameters of the burial mounds varying from 3 to 25.4 m, e.g. the Balikun-Dongheigou cemetery and the Balikun-Heigouliang cemetery. The Yiwu-Bai’erqi and the Yiwu-Kuola cemeteries contained either round stone burial mounds or circular stone kerbs on the ground surface. Considering the three burial elements including burial mounds, stone pits and circular kerbs, the later period cemeteries in the Balikun Grassland were actually similar to cemeteries from the southern edge of the Altai Mountain area.

From Shuicheng (2006):

The Nanwan 南湾 cemetery site at Kuisu 奎苏 Town, Balikun 巴里坤 (1600–1100 BC) also yielded an assemblage of early bronzes. The style of its early phase artifacts is similar to that of the burials distributed in the North Tianshan Route. Some sorts of cultural connection should have existed between the two.

The dates of Yanbulake 焉不拉克 Culture (1300–700 BC) are comparatively late. Its metallurgy was a continuation of the western China tradition. Artifact types include a variety of utilitarian tools, weapons and apparels.

tocharians-bronze-age-late
Prehistoric cultures of Xinjiang during the Late Bronze Age. See full culture and ancient DNA maps.

3.3. The Turpan Basin-the middle part of Tian Shan

From Yang (2019):

Turpan Basin is located at the western part of the Hami Basin, and lies at the southern edge of the eastern Tian Shan. In the Turpan Basin-the middle part of Tian Shan area, the main representative of the Bronze Age cemeteries is the Yanghai Nr.1 cemetery. The features here were:

  • Elliptic earth pit graves, commonly covered by round logs on the top;
  • Some graves contained burial beds made of round logs or reeds;
  • The dead were mainly placed lying straight on the back;
  • Mostly a single dead in one grave.

In Iron Age, the stone burials became dominant, but the stone burials varied in different regions of the Turpan Basin-the middle part of Tian Shan area. Graves containing burial mounds, stone pit, and circular stone kerbs are represented by the Shanshan-Ertanggou cemetery, the Tuokexun-Alagou cemetery, the Urumqi-Chaiwobu cemetery and the Urumqi-Yizihu-Sayi cemetery, etc. The stone funeral construction features here are similar to those contemporary cemeteries in the Hami Basin-the Balikun Grassland area.

3.4. The southern edge of the western and middle part of Tian Shan

In the southern edge of the western and middle part of Tian Shan area, the main representatives of the late Bronze Age cemeteries are the Hejing-Chawuhu Nr.4 cemetery (around 1000-500 bce), the Hejing-Xiaoshankou cemetery, the Baicheng-cemetery, etc. The main burial features of the late Bronze Age and the early Iron Age cemeteries (see Fig.12) here were:

  • Burial mounds, constructed by stones or a mix of stones and earth;
  • Irregular circular or rectangular stone kerbs;
  • Stone pit graves in a bell-shape or a rectangular shape;
  • Stone pit graves constructed by imbedding pebbles or stone slabs in walls and floors;
  • The dead were often placed lying on their back with bent legs;
  • The dead were commonly reburied a second time with multiple burials.

From the late Bronze Age to the early Iron Age in this area, the burial traditions tended to be in a more varied way. In the stone burials with stone kerbs, there is a mixture of stone pit and earth pit graves. The burial features of the Iron Age cemeteries in this section were similar to those contemporary both in the Hami Basin-the Balikun Grassland area and in the Turpan Basin-the middle part of Tian Shan area.

From Shuicheng (2006):

The Chawuhu 察吾呼 Culture (1100–500 BC) distributes on the foothills between the middle section of the Tianshan Mountain Ranges and Tarim River. Its bronze assemblage comprises a variety of weapons, utilitarian tools and small apparels. They show no apparent temporal change in form and type through the four cultural phases. In addition, bronzes bear the Chawuhu characteristics were found in Hejing 和静, Baicheng 拜城 and Luntai 轮台 (Bügür). Yet, sites distributed along the Tarim River, such as Heshuo 和硕, Kuga 库车and Aksu 阿克苏, yielded remains of a bronze culture different from that of Chawuhu. Bronzes recovered include double-eared socketed axe, arrowheads, awls, knives, needles and bracelets. Their absolute dates have been estimated to be earlier than that of Chawuhu.

tocharians-iron-age-early
Prehistoric cultures of Xinjiang during the Early Iron Age. See full culture and ancient DNA maps

3.5. The Pamir Plateau

From Yang (2019):

A typical Bronze Age cemetery from the Pamir Plateau area is the Tashenku’ergan-Xiabandi cemetery (around 1000-500 bce). The burial features here were:

  • Mainly inhumations, but also a few cremations;
  • Burial mounds, constructed of stones;
  • Irregular circular or rectangular stone kerbs;
  • Mostly a single dead in one grave;
  • The dead was placed in a hocker position lying on one side.

The adoption of burial customs from the east supports the migration of Afanasievo-related peoples from the Tian Shan up to the Pamir Plateau, strongly influencing the findings of the Xiabandi cemetery, which has been dated from an early Bronze Age phase (ca. 1500-300 BC) to a late date up to ca. 600 BC.

While it is today unclear how far the Afanasievo admixture reached into the western Xinjiang, it seems that the Pamir Plateau remained culturally connected to neighbouring Andronovo-related cultures in pottery and metallurgical innovations, hence their language probably belonged – during most part of the Bronze and Iron Ages – to the Indo-Iranian branch, even though specific dialects might have changed with each new attested group.

In particular, it is possible that the early Andronovo groups related to the Xiaohe Horizon spoke Indo-Aryan or West Iranian dialects, while Saka-related groups replaced them – or an intermediate Tocharian-speaking group – with East Iranian dialects. A close interaction with West Iranian would justify the known ancient borrowings of Tocharian, although they could also be explained by contacts with Chust-related groups farther west. For more on this, see Ged Carling’s work on the different layers of Iranian loans.

Xinjiang BA/IA Summary

From Yang (2019):

In the early Bronze Age, there are distinct regional differences in the burial customs in and surrounding the Tarim Basin. At the southern edge of the Altai Mountains area, the burial customs included stone burial mounds, stone pit graves, circular or rectangular stone kerbs and stone human sculptures; the dead were placed lying straight on the back. In the Hami Basin-the Balikun Grassland area, the burial customs included earth pit graves; the dead were placed in a hocker position lying on one side. In the Turpan Basin-the middle part of Tian Shan area, the burial customs included earth pit graves; the dead were placed lying straight on the back. In the Lop Nur region, the burial customs included wooden coffins buried in sand; the dead were placed lying straight on the back.

But from the late Bronze Age to the early Iron Age, there was a common shift in burial customs from earth pit graves to stone burials in the Hami Basin-the Balikun Grassland area and in the Turpan Basin-the middle part of Tian Shan area. The main features of the stone burials include stone burial mounds, circular or rectangular stone kerbs, and the stone pit graves in the cemeteries. Similar stone burial customs commonly appeared at the southern edge of the western and middle part of Tian Shan area and the Pamir Plateau area in Iron Age. The burial features in most areas are in a mixture of both the earth pit graves and stone pit graves, especially in the Hami Basin-the Balikun Grassland area and the Turpan Basin-the middle part of Tian Shan area.

xinjiang-bronze-age-iron-age

From Shuicheng (2006):

Historians of metallurgy conducted metallographic analyses on a sample of 234 metal specimens recovered from 16 localities in eastern Xinjiang. They concluded that the metallurgic industry in eastern Xinjiang could be roughly partitioned into three developmental phases. The early phase is represented by the burials distributed in the North Tianshan Route. The majority of the metal assemblage was tin-bronzes; however, copper and arsenic-bronzes maintained considerable proportions. The middle phase is represented by the burials at Yanbulake. During this phase, tin-bronze still maintained the majority; the proportion of arsenic-bronze increased, and some of them were high arsenic-bronzes. The late phase is represented by the burials at Heigouliang 黑沟梁. The composition of lead increased in the bronze alloy in the expense of arsenic. In addition, this phase witnessed the appearance of high tin-bronze that composed up to 16% of tin and the appearance of brass, that is, an alloy of copper and zinc. The bronze alloy consistently contained significant amount of impurities regardless of temporal difference. Casting and forging technologies coexisted throughout the three phases. The early bronzes (2000–500 BC) of eastern Xinjiang, in general, contained arsenic; however, the composition of arsenic was usually under 8%, but a few artifacts contained more than 20% arsenic. In all, arsenic had long been used in the alloy-forming of the early bronzes in eastern Xinjiang. Consequently, arsenic-bronzes were widely found in the prehistoric archaeology of the region. The artifact types, chemical compositions and manufacture techniques of the bronze assemblage of the burials of the North Tianshan Route are similar to those of Siba Culture, indicating that eastern Xinjiang had played a significant role in the East-West interactions.

An assemblage of early bronzes had been recovered from northwestern Xinjiang and the periphery of Dzungaria 准噶尔 Basin. It comprises a variety of utilitarian tools and weapons, and a small number of apparels. These artifacts bear the stamps of Andronovo Culture in form, artifact type and decorative pattern. The metallographic analysis on selected artifacts indicates that they comprise mainly of tin-bronzes that contain 2–10% of tin. Moreover, the chemical compositions of these artifacts are similar to that of the Andronovo Culture. Latter date (first half of the 1st millennium BC) artifacts of the assemblage include a small number of arsenic-bronzes. In all, during the period between the mid-2nd and mid-1st millennium BC, copper and bronze artifacts coexisted in this region, albeit tin-bronze comprised the majority.

tocharians-iron-age-late
Prehistoric cultures of Xinjiang during the Late Iron Age. See full culture and ancient DNA maps.

Tocharians in population genomics

Prehistoric population movements between the Altai and the Tian Shan are difficult to pinpoint, not the least because of the division of these territories among three different countries and their archaeological teams, only recently (more) open to the international scholarship.

The available schematic archaeological picture, where migrations could only be roughly inferred, has been recently updated to a great extent by Ning, Wang et al. (2019), whose genetic analysis of the samples is as thorough as anyone could have asked for, with a level of detail which matches the complex genetic picture of the region by the Iron Age.

As a summary, here is what they described about the samples from Shirenzigou (ca 400-200 BC), corresponding to the Iron Age populations of the Hami Basin-the Balikun Grassland area, and closely related to the preceding Yanbulake Culture:

As shown in Figure S3, the Steppe_MLBA populations including Srubnaya, Andronovo, and Sintashta were shifted toward farming populations compared with Yamnaya groups and the Shirenzigou samples. This observation is consistent with ADMIXTURE analysis that Steppe_MLBA populations have an Anatolian and European farmer-related component that Yamnaya groups and the Shirenzigou individuals do not seem to have. The analysis consistently suggested Yamnaya-related Steppe populations were the better source in modeling the West Eurasian ancestry in Shirenzigou.

biplot-yamnaya-tocharians-shirenzigou
Biplot of f3-outgroup tests illustrating the Kostenki14 and Anatolia_N like ancestries in Shirenzigou individuals. Most Shirenzigou individuals were on a cline with Yamnaya and European hunter-gatherer groups, lacking the European farmer ancestry as compared to the Steppe_MLBA populations such as Andronovo, Srubnaya and Sintashta [S1-S5]. Horizontal and vertical bars represent ± 3 standard errors, corresponding to form of outgroup f3 tests on the x axis and y axis respectively.

We continued to use qpAdm to estimate the admixture proportions in the Shirenzigou samples by using different pairs of source populations, such as Yamnaya_Samara, Afanasievo, Srubnaya, Andronovo, BMAC culture (Bustan_BA and Sappali_ Tepe_BA) and Tianshan_Hun as the West Eurasian source and Han, Ulchi, Hezhen, Shamanka_EN as the East Eurasian source. In all cases, Yamnaya, Afanasievo, or Tianshan_Hun always provide the best model fit for the Shirenzigou individuals, while Srubnaya, Andronovo, Bustan_BA and Sappali_Tepe_BA only work in some cases.

p-values-shirenzigou-samples-han-chinese
Table S2. P values in modelling a two-way (P=rank 1) admixture in Shirenzigou samples using each of the four populations (Bustan_BA, Sappali_Tepe_BA, Andronovo.SG, Srubnaya) together with Han Chinese as two sources [S6], Related to Figure 2. We used the following set of outgroups populations: Dinka, Ust_Ishim, Kostenki14, Onge, Papuan, Australian, Iran_N, EHG, LBK_EN.

shirenzigou-afanasievo-yamnaya-andronovo-srubna-ulchi-han

In the PCA, ADMIXTURE, outgroup f3 statistics [see Figure S4], as well as f4 statistics (Table S3), we observed the Shirenzigou individuals were closer to the present day Tungusic and Mongolic-speaking populations in northern Asia than to the populations in central and southern China, suggesting the northern populations might contribute more to the Shirenzigou individuals. Based on this, we then modeled Shirenzigou as a three-way admixture of Yamnaya_Samara, Ulchi (or Hezhen) and Han to infer the source from the East Eurasia side that contributed to Shirenzigou. We found the Ulchi or Hezhen and Han-related ancestry had a complicated and unevenly distribution in the Shirenzigou samples. The most Shirenzigou individuals derived the majority of their East Eurasian ancestry from Ulchi or Hezhen-related populations, while the following two individuals M820 and M15-2 have more Han related than Ulchi/ Hezhen-related ancestry

It is unclear whether the Chemurchek population will show a sizeable local contribution from neighbouring groups. The fact that Okunevo shows 20% Yamnaya-related ancestry strongly supports the nature of neighbouring stone-grave-building peoples of the Altai and the northern Tian Shan as mostly Afanasievo-like, and the apparent lack of contributions of Srubna/Andronovo-like ancestry in the early Hami-Balikun stone burial builders also speaks for radical population replacement events reaching the areas south of Tian Shan, at least initially.

While ancestry cannot settle linguistic questions, it seems that nomads of the Gansu and Qinghai grasslands retained an ancestry close to Andronovo, whereas nomads of the Hami Basin-Balikun grasslands and related populations of Xinjiang remained closely related to Afanasievo. This doesn’t preclude that the ancestors of the Yuezhi became acculturated under the influence of peoples from eastern Xinjiang, but all data combined suggest an isolation of both populations – relative to other groups and to each other – and it is therefore more likely that they spoke Indo-Iranian-related languages rather than a language of the Tocharian branch.

Haplogroups

In an interesting twist of events, despite the initially reported hg. R1b and Q, Tocharians from Shirenzigou actually show a haplogroup diversity comparable to that attested in other late Iron Age populations: a similar diversity is seen, for example, among Germanic, Baltic, and Balto-Finnic peoples of the Baltic region; among East Germanic or Scythians of the north Pontic region; or among Mediterranean peoples sampled to date. Iron Age peoples show thus a complex sociopolitical setting that overcame the previous patrilineal homogeneity of Bronze Age expansions.

tocharians-pca
PCA and ADMIXTURE for Shirenzigou Samples. Modified from the original to include in black squares samples related to Yamnaya. Modified from the paper to include labels of modern populations and a dotted lines with the cline formed by Shirenzigou, from (Yamnaya-like) Afanasievo to Central and East Asian-like populations. In red circles, samples with best fit for Andronovo-like ancestry. In green circles, samples with Han-related admixture.

M15-2 (with Han-related ancestry) is of the rare haplogroup Q1a-M120, while the samples with highest Steppe_MLBA-related ancestry are of hg. R1b-PH155, which points to their recent origin among Yuezhi, or to Hun-related populations showing an admixture related to the proto-historic nomads of the Gansu and Qinghai grasslands.

The expansion of Chemurchek-related peoples was probably associated more with hg. Q1a (dubious if it’s a Pre-ISOGG 2017 nomenclature, hence possibly Q1b), a haplogroup that might be found in Khvalynsk as a “significant minority” according to Anthony (2019), and it might also be attested in sampled individuals from Afanasievo in its late phase. This might be, therefore, a case similar to the early expansion of Indo-Europeans with R1b-V1636 lineages through the Volga – North Caucasus region, and of the later expansion with I2a-L699 lineages into the Balkans.

Haplogroup Q1a2-M25 is found in individual X3, whose Steppe ancestry is likely a combination of Afanasievo plus Andronovo-like ancestry heavily admixed with Hezhen/Ulchi-like populations, in line with the expected recent contacts with the neighbouring Xiongnu, Yuezhi, and other population movements affecting eastern Xinjiang.

Sample M4, which packs the most Afanasievo-like ancestry, is of hg. R1a-Z645, which – like sample M8R1 of hg. O – is most likely related to haplogroup resurgence events of local populations, which left the predominant Afanasievo-like admixture brought by builders of stone burials essentially intact, evidenced by the almost 100% of R1a found in the Xiaohe cemetery – and in most of the early Andronovo horizon – and among expanding Kangju and Wusun, as well as by the prevalence of hg. O among sampled East Asian populations.

A question that will only be answered with more samples is how and when the prevalent R1b-L23 and Q1b lineages among Afanasievo-related peoples began to be replaced to reach the high variability seen in Shirenzigou. Given the pastoralist nature of peoples around Tian Shan, the succeeding expansions of Proto-Tocharians, and the late isolation of different Common Tocharian groups, it is more than likely that this variability represents a late and local phenomenon within Xinjiang itself.

tocharians-antiquity
Peoples of Xinjiang during Antiquity. See full culture and ancient DNA maps.

Conclusion

Tocharians are one of the main pillars that confirm the Late Proto-Indo-European homeland of the R1b-rich populations of the Don-Volga region. There is already:

Just like the East Bell Beaker expansion from Yamnaya Hungary has confirmed that Corded Ware peoples did not partake in spreading Indo-European languages (spreading Uralic languages instead), data on the expansion of Tocharian speakers from Afanasievo to the Tian Shan was always there; population genomics is merely helping to connect the dots.

In summary, genetic research is supporting the expected linguistic expansions of the Neolithic and Bronze Age step by step, slowly but surely.

Related

N1c-L392 associated with expanding Turkic lineages in Siberia

haplogroup-n1c-tat

Second in popularity for the expansion of haplogroup N1a-L392 (ca. 4400 BC) is, apparently, the association with Turkic, and by extension with Micro-Altaic, after the Uralic link preferred in Europe; at least among certain eastern researchers.

New paper in a recently created journal, by the same main author of the group proposing that Scythians of hg. N1c were Turkic speakers: On the origins of the Sakhas’ paternal lineages: Reconciliation of population genetic / ancient DNA data, archaeological findings and historical narratives, by Tikhonov, Gurkan, Demirdov, and Beyoglu, Siberian Research (2019).

Interesting excerpts:

According to the views of a number of authoritative researchers, the Yakut ethnos was formed in the territory of Yakutia as a result of the mixing of people from the south and the autochthonous population [34].

These three major Sakha paternal lineages may have also arrived in Yakutia at different times and/ or from different places and/or with a difference in several generations instead, or perhaps Y-chromosomal STR mutations may have taken place in situ in Yakutia. Nevertheless, the immediate common ancestor(s) from the Asian Steppe of these three most prevalent Sakha Y-chromosomal STR haplotypes possibly lived during the prominence of the Turkic Khaganates, hence the near-perfect matches observed across a wide range of Eurasian geography, including as far as from Cyprus in the West to Liaoning, China in the East, then Middle Lena in the North and Afghanistan in the South (Table 3 and Figure 5). There may also be haplotypes closely-related to ‘the dominant Elley line’ among Karakalpaks, Uzbeks and Tajiks, however, limitations in the loci coverage for the available dataset (only eight Y-chromosomal STR loci) precludes further conclusions on this matter [25].

yakutia-haplogroup-n1c
17-loci median-joining network analysis of the original/dominant Elley, Unknown and Omogoy Y-chromosomal STR haplotypes with the YHRD matches from outside Yakutia populations.

According to the results presented here, very similar Y-STR haplotypes to that of the original Elley line were found in the west: Afghanistan and northern Cyprus, and in the east: Liaoning Province, China and Ulaanbaator, Northern Mongolia. In the case of the dominant Omogoy line, very closely matching haplotypes differing by a single mutational step were found in the city of Chifen of the Jirin Province, China. The widest range of similar haplotypes was found for the Yakut haplotype Unknown: In Mongolia, China and South Korea. For instance, haplotypes differing by a single step mutation were found in Northern Mongolia (Khalk, Darhad, Uryankhai populations), Ulaanbaator (Khalk) and in the province of Jirin, China (Han population).

n1c-uralic-altaic-siberia
14-loci median-joining network analysis for the original/dominant Elley (Ell), Unknown Clan
(Vil), Omogoy (Omo), Eurasian (Eur) and Xiongnu (Xuo) Y-chromosomal STR haplotypes and that for a representative ancient DNA sample (Ch0 or DSQ04) from the Upper Xiajiadian Culture
recovered from the Inner Mongolia Autonomous Region, China.

Notably, Tat-C-bearing Y-chromosomes were also observed in ancient DNA samples from the 2700-3000 years-old Upper Xiajiadian culture in Inner Mongolia, as well as those from the Serteya II site at the Upper Dvina region in Russia and the ‘Devichyi gory’ culture of long barrow burials at the Nevel’sky district of Pskovsky region in Russia. A 14-loci Y-chromosomal STR median-joining network of the most prevalent Sakha haplotypes and a Tat-C-bearing haplotype from one of the ancient DNA samples recovered from the Upper Xiajiadian culture in Inner Mongolia (DSQ04) revealed that the contemporary Sakha haplotype ‘Xuo’ (Table 2, Haplotype ID “Xuo”) classified as that of ‘the Xiongnu clan’ in our current study, was the closest to the ancient Xiongnu haplotype (Figure 6). TMRCA estimate for this 14-loci Y-chromosomal STR network was 4357 ± 1038 years or 2341 ± 1038 BCE, which correlated well with the Upper Xiajiadian culture that was dated to the Late Bronze Age (700-1000 BCE).

eurasian-n-subclades
Geographical location of ancient samples belonging to major clade N of the Y-chromosome.

NOTE. Also interesting from the paper seems to be the proportion of E1b1b among admixed Russian populations, in a proportion similar to R1a or I2a(xI2a1).

It is tempting to associate the prevalent presence of N1c-L392 in ancient Siberian populations with the expansion of Altaic, by simplistically linking the findings (in chronological order) near Lake Baikal (Damgaard et al. 2018), Upper Xiajiadian (Cui et al. 2013), among Khövsgöl (Jeong et al. 2018), in Huns (Damgaard et al. 2018), and in Mongolic-speaking Avars (Csáky et al. 2019).

However, its finding among Palaeo-Laplandic peoples in the Kola peninsula ca. 1500 BC (Lamnidis et al. 2018) and among Palaeo-Siberian populations near the Yana River (Sikora et al. 2018) ca. AD 1200 should be enough to accept the hypothesis of ancestral waves of expansion of the haplogroup over northern Eurasia, with acculturation and further expansions in the different regions since the Iron Age (see more on its potential expansion waves).

Also, a simple look at the TMRCA and modern distribution was enough to hypothesize long ago the lack of connection of N1c-L392 with Altaic or Uralic peoples. From Ilumäe et al. (2016):

Previous research has shown that Y chromosomes of the Turkic-speaking Yakuts (Sakha) belong overwhelmingly to hg N3 (formerly N1c1). We found that nearly all of the more than 150 genotyped Yakut N3 Y chromosomes belong to the N3a2-M2118 clade, just as in the Turkic-speaking Dolgans and the linguistically distant Tungusic-speaking Evenks and Evens living in Yakutia (Table S2). Hence, the N3a2 patrilineage is a prime example of a male population of broad central Siberian ancestry that is not intrinsic to any linguistically defined group of people. Moreover, the deepest branch of hg N3a2 is represented by a Lebanese and a Chinese sample. This finding agrees with the sequence data from Hallast et al., where one Turkish Y chromosome was also assigned to the same sub-clade. Interestingly, N3a2 was also found in one Bhutan individual who represents a separate sub-lineage in the clade. These findings show that although N3a2 reflects a recent strong founder effect primarily in central Siberia (Yakutia, Sakha), the sub-clade has a much wider distribution area with incidental occurrences in the Near East and South Asia.

haplogroup-n1a-M2118
Frequency-Distribution Maps of Individual Sub-clades of hg N3a2, by Ilumäe et al. (2016).

The most striking aspect of the phylogeography of hg N is the spread of the N3a3’6-CTS6967 lineages. Considering the three geographically most distant populations in our study—Chukchi, Buryats, and Lithuanians—it is remarkable to find that about half of the Y chromosome pool of each consists of hg N3 and that they share the same sub-clade N3a3’6. The fractionation of N3a3’6 into the four sub-clades that cover such an extraordinarily wide area occurred in the mid-Holocene, about 5.0 kya (95% CI = 4.4–5.7 kya). It is hard to pinpoint the precise region where the split of these lineages occurred. It could have happened somewhere in the middle of their geographic spread around the Urals or further east in West Siberia, where current regional diversity of hg N sub-lineages is the highest (Figure 1B). Yet, it is evident that the spread of the newly arisen sub-clades of N3a3’6 in opposing directions happened very quickly. Today, it unites the East Baltic, East Fennoscandia, Buryatia, Mongolia, and Chukotka-Kamchatka (Beringian) Eurasian regions, which are separated from each other by approximately 5,000–6,700 km by air. N3a3’6 has high frequencies in the patrilineal pools of populations belonging to the Altaic, Uralic, several Indo-European, and Chukotko-Kamchatkan language families. There is no generally agreed, time-resolved linguistic tree that unites these linguistic phyla. Yet, their split is almost certainly at least several millennia older than the rather recent expansion signal of the N3a3’6 sub-clade, suggesting that its spread had little to do with linguistic affinities of men carrying the N3a3’6 lineages.

haplogroup_n3a3
Frequency-Distribution Maps of Individual Subclade N3a3 / N1a1a1a1a1a-CTS2929/VL29.

It was thus clear long ago that N1c-L392 lineages must have expanded explosively in the 5th millennium through Northern Eurasia, probably from a region to the north of Lake Baikal, and that this expansion – and succeeding ones through Northern Eurasia – may not be associated to any known language group until well into the common era.

Related

Minimal gene flow from western pastoralists in the Bronze Age eastern steppes

jeong-steppes-mongolia

Open access paper Bronze Age population dynamics and the rise of dairy pastoralism on the eastern Eurasian steppe, by Jeong et al. PNAS (2018).

Interesting excerpts (emphasis mine):

To understand the population history and context of dairy pastoralism in the eastern Eurasian steppe, we applied genomic and proteomic analyses to individuals buried in Late Bronze Age (LBA) burial mounds associated with the Deer Stone-Khirigsuur Complex (DSKC) in northern Mongolia. To date, DSKC sites contain the clearest and most direct evidence for animal pastoralism in the Eastern steppe before ca. 1200 BCE.

Most LBA Khövsgöls are projected on top of modern Tuvinians or Altaians, who reside in neighboring regions. In comparison with other ancient individuals, they are also close to but slightly displaced from temporally earlier Neolithic and Early Bronze Age (EBA) populations from the Shamanka II cemetry (Shamanka_EN and Shamanka_EBA, respectively) from the Lake Baikal region. However, when Native Americans are added to PC calculation, we observe that LBA Khövsgöls are displaced from modern neighbors toward Native Americans along PC2, occupying a space not overlapping with any contemporary population. Such an upward shift on PC2 is also observed in the ancient Baikal populations from the Neolithic to EBA and in the Bronze Age individuals from the Altai associated with Okunevo and Karasuk cultures.

pca-eurasians-karasuk-khovsgol
Image modified from the article. Karasuk cluster in green, closely related to sample ARS026 in red. Principal Component Analysis (PCA) of selected 2,077 contemporary Eurasians belonging to 149 groups. Contemporary individuals are plotted using three-letter abbreviations for operational group IDs. Group IDs color coded by geographic region. Ancient Khövsgöl individuals and other selected ancient groups are represented on the plot by filled shapes. Ancient individuals are projected onto the PC space using the “lsqproject: YES” option in the smartpca program to minimize the impact of high genotype missing rate.

(…) two individuals fall on the PC space markedly separated from the others: ARS017 is placed close to ancient and modern northeast Asians, such as early Neolithic individuals from the Devil’s Gate archaeological site (22) and present-day Nivhs from the Russian far east, while ARS026 falls midway between the main cluster and western Eurasians.

Upper Paleolithic Siberians from nearby Afontova Gora and Mal’ta archaeological sites (AG3 and MA-1, respectively) (25, 26) have the highest extra affinity with the main cluster compared with other groups, including the eastern outlier ARS017, the early Neolithic Shamanka_EN, and present-day Nganasans and Tuvinians (Z > 6.7 SE for AG3). Main cluster Khövsgöl individuals mostly belong to Siberian mitochondrial (A, B, C, D, and G) and Y (all Q1a but one N1c1a) haplogroups.

mongolia-botai-ehg-ane-cline
The genetic affinity of the Khövsgöl clusters measured by outgroup-f3 and -f4 statistics. (A) The top 20 populations sharing the highest amount of >genetic drift with the Khövsgöl main cluster measured by f3(Mbuti; Khövsgöl, X). (B) The top 15 populations with the most extra affinity with each of the three Khövsgöl clusters in contrast to Tuvinian (for the main cluster) or to the main cluster (for the two outliers), measured by f4(Mbuti, X; Tuvinian/Khövsgöl, Khövsgöl/ARS017/ARS026). Ancient and contemporary groups are marked by squares and circles, respectively. Darker shades represent a larger f4 statistic.

Previous studies show a close genetic relationship between WSH populations and ANE ancestry, as Yamnaya and Afanasievo are modeled as a roughly equal mixture of early Holocene Iranian/ Caucasus ancestry (IRC) and Mesolithic Eastern European hunter-gatherers, the latter of which derive a large fraction of their ancestry from ANE. It is therefore important to pinpoint the source of ANE-related ancestry in the Khövsgöl gene pool: that is, whether it derives from a pre-Bronze Age ANE population (such as the one represented by AG3) or from a Bronze Age WSH population that has both ANE and IRC ancestry.

The amount of WSH contribution remains small (e.g., 6.4 ± 1.0% from Sintashta). Assuming that the early Neolithic populations of the Khövsgöl region resembled those of the nearby Baikal region, we conclude that the Khövsgöl main cluster obtained ∼11% of their ancestry from an ANE source during the Neolithic period and a much smaller contribution of WSH ancestry (4–7%) beginning in the early Bronze Age.

khovsgol-shamanka-sintashta
Admixture modeling of Altai populations and the Khövsgöl main cluster using qpAdm. For the archaeological populations, (A) Shamanka_EBA and (B and C) Khövsgöl, each colored block represents the proportion of ancestry derived from a corresponding ancestry source in the legend. Error bars show 1 SE. (A) Shamanka_EBA is modeled as a mixture of Shamanka_EN and AG3. The Khövsgöl main cluster is modeled as (B) a two-way admixture of Shamanka_EBA+Sintashta and (C) a three-way admixture Shamanka_EN+AG3+Sintashta.

Apparently, then, the first individual with substantial WSH ancestry in the Khövsgöl population (ARS026, of haplogroup R1a-Z2123), directly dated to 1130–900 BC, is consistent with the first appearance of admixed forest-steppe-related populations like Karasuk (ca. 1200-800 BC) in the Altai. Interestingly, haplogroup N1a1a-M178 pops up (with mtDNA U5a2d1) among the earlier Khövsgöl samples.

I will repeat what I wrote recently here: Samoyedic arrived in the Altai with Karasuk and hg R1a-Z645 + Steppe_MLBA-like ancestry, admixed with Altai populations, clustering thus within an Ancient Altai cline. Only later did N1a1a subclades infiltrate Samoyedic (and Ugric) populations, bringing them closer to their modern Palaeo-Siberian cline. The shared mtDNA may support an ancestral EHG-“Siberian” cline, or else a more recent Afanasevo-related origin.

east-uralic-clines
Modified image from Jeong et al. (2018), supplementary materials. 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 north-south 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. Read more.

Also interesting, Q1a2 subclades and ANE ancestry making its appearance everywhere among ancestral Eurasian peoples, as Chetan recently pointed out.

Related

The Iron Age expansion of Southern Siberian groups and ancestry with Scythians

iron_age-sarmatians

Maternal genetic features of the Iron Age Tagar population from Southern Siberia (1st millennium BC), by Pilipenko et al. (2018).

Interesting excerpts (emphasis mine):

The positions of non-Tagar Iron Age groups in the MDS plot were correlated with their geographic position within the Eurasian steppe belt and with frequencies of Western and Eastern Eurasian mtDNA lineages in their gene pools. Series from chronological Tagar stages (similar to the overall Tagar series) were located within the genetic variability (in terms of mtDNA) of Scythian World nomadic groups (Figs 5 and 6; S4 and S6 Tables). Specifically, the Early Tagar series was more similar to western nomads (North Pontic Scythians), while the Middle Tagar was more similar to the Southern Siberian populations of the Scythian period. The Late Tagar group (Tes`culture) belonging to the Early Xiongnu period had the “western-most” location on the MDS plot with the maximal genetic difference from Xiongnu and other eastern nomadic groups (but see Discussion concerning the low sample size for the Tes`series).

In a comparison of our Tagar series with modern populations in Eurasia, we detected similarity between the Tagar group and some modern Turkic-speaking populations (with the exception of the Indo-Iranian Tajik population) (Fig 7; S2 Table). Among the modern Turkic-speaking groups, populations from the western part of the Eurasian steppe belt, such as Bashkirs from the Volga-Ural region and Siberian Tatars from the West Siberian forest-steppe zone, were more similar to the Tagar group than modern Turkic-speaking populations of the Altay-Sayan mountain system (including the Khakassians from the Minusinsk basin) (Fig 7).

tagar-archaeology
Location of Tagar archaeological sites from which samples for this study were obtained. Burial grounds: 1—Novaya Chernaya-1; 2—Podgornoe Ozero, Barsuchiha-1, Barsuchiha-6, Barsuchiha-7; 3—Perevozinskiy; 4—Ulug-Kyuzyur, Kichik-Kyuzyur, Sovetskaya Khakassiya; 5—Tepsey-3, Tepsey-8, Tepsey-9; 6—Dolgiy Kurgan. https://doi.org/10.1371/journal.pone.0204062.g001

Mitochondrial DNA diversity and genetic relationships of the Tagar population

Our results are not inconsistent with the assumption of a probable role of gene flow due to the migration from Western Eurasia to the Minusinsk basin in the Bronze Age in the formation of the genetic composition of the Tagar population. Particularly, we detected many mtDNA lineages/clusters with probable West Eurasian origin that were dominant in modern populations of different parts of Europe, Caucasus, and the Near East (such as K and HV6) in our Tagar series based on a phylogeographic analysis.

We detected relatively low genetic distances between our Tagar population and two Bronze Age populations from the Minusinsk basin—the Okunevo culture population (pre-Andronovo Bronze Age) and Andronovo culture population, followed by Afanasievo population from the Minusinsk Basin and Middle Bronze Age population from the Mongolian Altai Mountains (the region adjacent to the Minusinsk basin) (Figs 3 and 6; S3 and S5 Tables). Among West Eurasian part of our Tagar series we also observed haplogroups/sub-haplogroups and haplotypes shared with Early and Middle Bronze Age populations from Minusinsk Basin and western part of Eurasian steppe belt (Fig 4; S5 Table). Thus, our results suggested a potentially significant role of the genetic components, introduced by migrants from Western Eurasia during the Bronze Age, in the formation of the genetic composition of the Tagar population. It is necessary to note the relatively small size of available mtDNA samples from the Bronze Age populations of Minusinsk basin; accordingly, additional mtDNA data for these populations are required to further confirm our inference.

tagar-mtdna-tree
Phylogenetic tree of mtDNA lineages from the Tagar population. Color coding of the Tagar stages: orange—the Early Tagar stage; blue—the Middle Tagar Stage; green—the Late Tagar stage. Color of haplogroup labels: yellow—for Western Eurasian haplogroups; red—for Eastern Eurasian haplogroups. https://doi.org/10.1371/journal.pone.0204062.g002

Another substantial part of the mtDNA pool of the Tagar and other eastern populations of the Scythian World is typical of populations in Southern Siberia and adjacent regions of Central Asia (autochthonous Central Asian mtDNA clusters). Most of these components belong to the East Eurasian cluster of mtDNA haplogroups. Moreover, the role of each of these components in the formation of the genetic composition of subsequent (to the present) populations in South Siberia and Central Asia could be very different. In this regard, cluster C4a2a (and its subcluster C4a2a1), and haplogroup A8 are of particular interest.

Genetic features of successive Tagar groups

We compared successive Tagar groups (Early, Middle, and Late Tagar) with each other and with other Iron Age nomadic populations to evaluate changes in the mtDNA pool structure. Despite the genetic similarity between the Early and Middle Tagar series and Scythian World nomadic groups (Figs 5 and 6; S4 and S6 Tables), there were some peculiarities. For example, the Early Tagar series was more similar to North Pontic Classic Scythians, while the Middle Tagar samples were more similar to the Southern Siberian populations of the Scythian period (i.e., completely synchronous populations of regions neighboring the Minusinsk basin, such as the Pazyryk population from the Altay Mountains and Aldy-Bel population from Tuva).

We observed differences in the mtDNA pool structure between the Early and the Middle chronological stages of the Tagar culture population, as evidenced by the change in the ratio of Western to Eastern Eurasian mtDNA components. The contribution of Eastern Eurasian lineages increased from about one-third (34.8%) in the Early Tagar group to almost one-half (45.8%) in the Middle Tagar group.

tagar-mtdna-fst
Results of multidimensional scaling based on matrix of Slatkin population differentiation (FST) according to frequencies of mtDNA haplogroup in Tagar populations and modern populations of Eurasia. Populations: Tagar (red pentagon) (this study); Mongolian-speaking populations: Khamnigans (Buryat Republic, Russia) [43]; Barghuts (Inner Mongolia, China) [44]; Buryats (Buryat Republic, Southern Siberia, Russia) [43]; Mongols (Mongolia) [45]. Turkic-speaking populations: Tuvinians (Tuva Republic, Russia) [43]; Tofalars (Irkutsk region, Russia) [46]; Altai-Kizhi ((Altai Republic, Russia) [43, 47]; Telenghits (Altai Republic, Russia) [43,47]; Tubalars (Altai Republic) [48]; Shors (Kemerovo region, Russia) [43, 47]; Khakassians (Khakassian Rupublic, Russia) [43, 46]; Altaian Kazakhs (Altai Republic) [49]; Kazakhs (Kazakhstan, Uzbekistan) [50, 51]; Kirghiz (Kyrgyzstan) [50, 51]; Uighurs (Kazakhstan and Xinjiang) [50, 52]; Siberian Tatars (Tyumen and Omsk regions, Russia) [53]; Tatars (Volga-Ural rigion, Russia) [54]; Bashkirs (Volga-Ural region, Russia) [55]; Uzbeks (Uzbekistan) [51, 56]; Turkmens (Turkmenistan) [51, 56]; Nogays [57]; Turkeys [58]; other populations: Evenks [43, 46]; Ulchi [59]; Koreans (South Korea) [43]; Han Chinese [60]; Zhuang (Guangxi, China) [61]; Tadjiks (Tadjikistan) [43, 51]; Iranians [60]; Russians [62]. https://doi.org/10.1371/journal.pone.0204062.g007

At the level of mtDNA haplogroups, we detected a decrease in the diversity of phylogenetic clusters during the transition from the Early Tagar to the Middle Tagar. This decline in diversity equally affected the West Eurasian and East Eurasian components of the Tagar mtDNA pool. It should be noted that this decrease can be partially explained by the smaller number of Middle Tagar than Early Tagar samples. Under a simple binomial approximation the mtDNA clusters, observed at frequencies of 6.3% and 11.7%, could be lost by chance in our Early (N = 46) and Middle (N = 24) Tagar samples, respectively. However, the simultaneous lack of several such clusters, with a total frequency in the gene pool of the Early group of 34.8%, is unlikely.

The observed reduction in the genetic distance between the Middle Tagar population and other Scythian-like populations of Southern Siberia(Fig 5; S4 Table), in our opinion, is primarily associated with an increase in the role of East Eurasian mtDNA lineages in the gene pool (up to nearly half of the gene pool) and a substantial increase in the joint frequency of haplogroups C and D (from 8.7% in the Early Tagar series to 37.5% in the Middle Tagar series). These features are characteristic of many ancient and modern populations of Southern Siberia and adjacent regions of Central Asia, including the Pazyryk population of the Altai Mountains. We did not obtain strong evidence for an intensification of genetic contact between the population of the Minusinsk basin and the Altai Mountains in the Middle Tagar period compared with the Early Tagar period. Although, several archaeologists have found evidence for the intensification of contact at the level of material culture, namely, a cultural influence of the population of the Altai Mountains (represented by the Pazyryk population) on the population of the Minusinsk basin (the Saragash Tagar group) [6, 71, 72].

Another important issue is the change in the genetic structure of the Tagar population during the transition from the Middle (Saragash) to the Late (Tes`) stage. The Late Tagar stage refers to the Xiongnu period. Many archaeologists suggest that the formation of the Tes`stage involved the direct cultural influence of the Xiongnu and/or related groups of nomads from more eastern regions of Central Asia [71, 73]. Some archaeologists have even suggested renaming the Tes`stage in the Tes`culture [71], emphasizing the role of new eastern cultural elements. If this influence also existed at the genetic level, then we would expect to observe new genetic elements in the Tes`gene pool, particularly those of East Eurasian origin.

Siberian ancestry

Just a reminder of the recent session in ISBA 8 on expanding Scythians (and also Mongolians and Turks) spreading Siberian ancestry, usually (wrongly) identified as “Uralic-Yeniseian” based on modern populations (similar to how steppe ancestry is wrongly identified as “Indo-European”), see the following graphic including the Tagar population:

siberian-genetic-component-chronology
Very important observation with implication of population turnover is that pre-Turkic Inner Eurasian populations’ Siberian ancestry appears predominantly “Uralic-Yeniseian” in contrast to later dominance of “Tungusic-Mongolic” sort (which does sporadically occur earlier). Alexander M. Kim

And also the poster by Alexander M. Kim et al. Yeniseian hypotheses in light of genome-wide ancient DNA from historical Siberia:

The relevance of ancient DNA data to debates in historical linguistics is an emphatic strand in much recent work on the archaeogenetics of Eurasia, where the discussion has focused heavily on Indo-European (Haak et al. 2015; Narasimhan et al. 2018; de Barros Damgaard et al. 2018a,b). We present new genome-wide ancient DNA data from a historical Siberian individual in relation to Yeniseian, an isolated language “microfamily” (Vajda 2014) that nonetheless sits at the center of numerous controversial proposals in historical linguistics and cultural interaction. Yeniseian’s sole surviving representative is Ket, a critically endangered language fluently spoken by only a few dozen individuals near the Middle Yenisei River of Central Siberia.

In strong contrast to the present-day picture, river names and argued substrate influences and loanwords in languages outside the current range of Yeniseian, as well as direct records from the Russian colonial period, indicate that speakers of extinct Yeniseian languages had a formerly much broader presence in the taiga of Central Siberia as well as further south in the mountainous Altai-Sayan region – and perhaps even further afield in Inner Asia (Vajda 2010; Gorbachov 2017; Blažek 2016). The consilience of these proposals with genetic data is not straightforward (Flegontov et al. 2015, 2017) and faces a major obstacle in the lack of genetic information from verifiable speakers of Yeniseian languages other than the Kets, who have had complex ongoing interactions with speakers of non-Yeniseian languages such as the Samoyedic Selkups. We attempt to remedy this with new historical Siberian aDNA data, orienting our search for common denominators and systematic difference in a broader landscape of concordance, discordance, and uncertainty at the interface of diachronic linguistics and genetics.

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Origins of equine dentistry in Mongolia in the early first millennium BC

New paper (behind paywall) Origins of equine dentistry, by Taylor et al. PNAS (2018).

Interesting excerpts (emphasis mine):

The practice of horse dentistry by contemporary nomadic peoples in Mongolia, coupled with the centrality of horse transport to Mongolian life, both now and in antiquity, raises the possibility that dental care played an important role in the development of nomadic life and domestic horse use in the past. To investigate, we conducted a detailed archaeozoological study of horse remains from tombs and ritual horse inhumations across the Mongolian Steppe, assessing evidence for anthropogenic dental modifications and comparing our findings with broader patterns in horse use and nomadic material culture.

We conducted a detailed study of archaeological horse collections spanning the past 3,200 y, including those from the Late Bronze Age DSK complex (ca. 1200–700 BCE, n = 70), Early Iron Age Slab Burial culture (ca. 700–300 BCE, n = 4), Pazyryk culture (ca. 600–200 BCE, n = 2), Late Iron Age Xiongnu Empire (ca. 200 BCE–200 CE, n = 3), Early Middle Ages post-Xiongnu period (ca. 100–550 CE, n = 3), and Turkic Khaganate (ca. 600–800 CE, n = 3).

horse-riding-mongolia
A (top): Contemporary Mongolian herder engaged in horseback riding, using left-handed rein position causing asymmetric pressures to the horse’s skull. Photo by Orsoo Bayarsaikhan. B(center) contemporary Mongolian horse skulls, showing asymmetric and skewed thinning to the nasal bones caused by bridle pressure. C(bottom) Asymmetric deformation to the cranial bones of a Deer Stone-Khirigsuur horse (left), alongside an early Middle Ages horse with a similar feature (right). Modified from Taylor and Tuvshinjargal (2018).

Discussion

This Late Bronze Age dental modification counts among the earliest documented instances of equine veterinary care, and the oldest known evidence for horse dentistry. At first glance, the detailed historical record of early equine veterinary care in places such as China, Greece, Rome, and Syria, which spans the late second millennium BCE through the early centuries CE (11, 15, 16), might imply that equine dentistry emerged in the sedentary civilizations of the Old World. However, the earliest textual references describe only nonsurgical medicinal treatments and make few mentions of oral health (11). Recent archaeological discoveries suggest that human care of domestic animals was practiced by hunter-gatherers as far back as the Paleolithic (46), and that pastoralists may have occasionally practiced surgical procedures on domestic animals as early as the Neolithic in Europe (47). The evidence presented here indicates that horse dentistry was developed by nomadic pastoralists living on the steppes of Mongolia and northeast Asia during the Late Bronze Age, concurrent with the local adoption of the metal bit and many centuries before the first mention of dental practices in historical accounts from sedentary Old World civilizations.

Our results reveal a fundamental link between equine dentistry and the emergence of horsemanship in the steppes of Eurasia. At the turn of the first millennium BCE, militarized, horse-mounted peoples reshaped the social and economic landscape of many areas of the Eurasian continent. Conflagrations with equestrian peoples, such as those between the Persian Empire and the Pontic “Scythians,” plagued alluvial civilizations from the Near East to India and China, while large-scale movements of people linked East and West in never-before-seen ways (48). The archaeological and historical records indicate that the earliest horseback riding was accomplished without stirrups or saddles, and probably using only bitless or organic-mouthpiece bridles (49, 50). The bronze snaffle bit, and the improved control it provided, was a key technological development that enabled the use of horseback riding for more stressful and difficult activities, such as long-distance transportation and warfare (32). We argue that these technological improvements in horse control were preceded and sustained by innovations in veterinary dentistry by nomadic peoples living in the continental interior. By increasing herd survival and mitigating behavioral and health issues caused by horse equipment, innovations in equine dentistry improved the reliability of horseback riding for ancient nomads, enabling horses to be used for nonpastoral activities like warfare, high-speed riding, and distance travel.

damage-tooth-horse
Damage to the retained wolf tooth in a 4-5 year old mummified horse, dating to the 2-4th centuries CE from the site of Urd Ulaan-Uneet in western Mongolia

Conclusion

Archaeozoological data from Mongolian horses indicate that the nomadic practice of equine dentistry dates back more than 3,000 y to the DSK complex, a Late Bronze Age culture associated with the first mounted horseback riding and mobile pastoralism in eastern Eurasia. Attempted removal of deciduous incisors through sawing of the exterior suggests experimentation with dental extraction, but not the removal of wolf teeth. The appearance of extracted first premolars in the first millennium BCE coincides with the arrival of metal bits in the archaeological record and oral trauma linked with metal bit use, suggesting that innovations in dental practice were an adaptation to the mechanical changes in horse equipment. These bronze and metal bits provided greater control over the horse, facilitating the development of military uses for the horse, but also introduced new dental problems with the first premolar. Our results indicate that, coincident with the earliest evidence for metal bit use, wolf tooth extraction was practiced in Mongolia by ca. 750 BCE and continued through the early Middle Ages. These results push back the earliest dates for equine dentistry by more than a millennium and suggest that nomadic peoples developed key innovations in veterinary care that enabled more sophisticated horse control, ultimately changing the structure of communication, exchange, and military power in ancient Eurasia.

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How an empire of steppe nomads coped with environmental stress

uyghur-empire

Recent paper (behind paywall), Environmental Stress and Steppe Nomads: Rethinking the History of the Uyghur Empire (744–840) with Paleoclimate Data, by Di Cosmo et al. JINH (2018) XLVIII(4):439-463.

Abstract (emphasis mine):

Newly available paleoclimate data and a re-evaluation of the historical and archaeological evidence regarding the Uyghur Empire (744–840)—one of several nomadic empires to emerge on the Inner Asian steppe—suggests that the assumption of a direct causal link between drought and the stability of nomadic societies is not always justified. The fact that a severe drought lasting nearly seven decades did not cause the Uyghur Empire to collapse, to wage war, or to disintegrate gives rise to speculations about which of its characteristics enabled it to withstand unfavorable climatic conditions and environmental change. More broadly, it raises questions about the complex suite of strategies and responses that may have been available to steppe societies in the face of environmental stress.

Interesting excerpts:

The heart of the matter is whether the apparent capacity to withstand adverse climatic conditions was due to a set of cultural and/or political choices, unrelated to climate, or to a modification of their nomadic ways toward a greater reliance on agriculture and trade. In support of the first alternative, the Uyghur Empire’s initial military rise and expansion (c. 744 to 780) may have been aided by conditions of high moisture that would have made the grasslands especially productive. The alliance with China, the conversion to Manichaeism, and the growing incorporation of Sogdian elites in their empire that took place during this period may have aided the Uyghurs, serendipitously, to withstand the climatic crisis. In the long run, however, some areas of society most likely suffered adverse effects, which might explain the internal splits and the final defeat at the hands of the Kirgiz. These developments owe as much to the sedentary habits of the Uyghur elites and their ineffective leadership as to the erosion of the pastoral resources that constituted the main support of a nomadic army.

uyghur-climate
The findings are based on scPDSI reconstructions at 0.5-degree grid derived from tree
ring records across Asia.

The evidence from tree-ring data points to environmental conditions that alter the historical narrative of the rise and fall of the Uyghur Empire. Although several studies have focused on how climatic extremes affected agricultural societies, the fate of complex nomadic societies did not necessarily follow the same path. Steppe empires, at least from the first Türk Empire (established in the sixth century C.E.), and possibly earlier, were based on expansive geographical networks, diversified economies, and a degree of co-dependency with merchant classes. Even though these elements varied greatly between empires, they probably reacted to climatic variability in ways radically different from the ways in which agricultural and urban polities did. Once we account for socio-economic complexity, the case of the Uyghur Empire belies the general assumption that nomadic peoples are more vulnerable to climatic stress. The severe and protracted drought did not trigger migration, pillaging, or conquest. Sudden shocks, however, could have had a devastating effect on an economy already weakened.

The catastrophic event of the winter of 839/40, which appears to be a dzud (a weather condition of extreme cold and heavy snowfall that causes high animal mortality) was likely the coup de grâce to an already compromised pastoral production. Contemporary studies of the dzud emphasize that the degree of calamity of the winter disaster is closely related to the drought conditions that preceded it. Thus, the collapse of the Uyghur Empire, generally understood as a rapidly evolving political crisis compounded by a catastrophic weather event, is also connected to multidecadal climatic change, dependency mechanisms, and geopolitical constraints.

I found it interesting mainly because of the potential application of this kind of studies to other previous steppe societies.

Discovered via news on Sapiens.org, posted by Spencer Wells.

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Decline of genetic diversity in ancient domestic stallions in Europe

Open access research article Decline of genetic diversity in ancient domestic stallions in Europe, by Wutke et al., Science (2018), 4(4):eaap9691.

Abstract (emphasis mine):

Present-day domestic horses are immensely diverse in their maternally inherited mitochondrial DNA, yet they show very little variation on their paternally inherited Y chromosome. Although it has recently been shown that Y chromosomal diversity in domestic horses was higher at least until the Iron Age, when and why this diversity disappeared remain controversial questions. We genotyped 16 recently discovered Y chromosomal single-nucleotide polymorphisms in 96 ancient Eurasian stallions spanning the early domestication stages (Copper and Bronze Age) to the Middle Ages. Using this Y chromosomal time series, which covers nearly the entire history of horse domestication, we reveal how Y chromosomal diversity changed over time. Our results also show that the lack of multiple stallion lineages in the extant domestic population is caused by neither a founder effect nor random demographic effects but instead is the result of artificial selection—initially during the Iron Age by nomadic people from the Eurasian steppes and later during the Roman period. Moreover, the modern domestic haplotype probably derived from another, already advantageous, haplotype, most likely after the beginning of the domestication. In line with recent findings indicating that the Przewalski and domestic horse lineages remained connected by gene flow after they diverged about 45,000 years ago, we present evidence for Y chromosomal introgression of Przewalski horses into the gene pool of European domestic horses at least until medieval times.

horses-y-chromosome-evolution
The frequencies of Y chromosome haplotypes started to change during the Late Bronze Age (1600–900 BCE).
Inferred temporal trajectories of haplotype frequencies. Each haplotype is displayed by a different color. The shaded area represents the 95% highest-density region. The trajectories were constructed taking the median values across frequencies from the simulations of the Bayesian posterior sample. The small chart represents the stacked frequencies; the amplitude of each colored area is proportional to the median haplotype frequencies (normalized) at a given time. The x and y axes of the small chart match those in the large one. Ka, thousands of years.

Interesting excerpts:

The first record of the modern domestic Y chromosome haplotype stems from two Bronze Age samples of similar age. Notably, both samples were found in two distantly located regions: present-day Slovakia (2000–1600 BCE, dated by archaeological context) and western Siberia (14C-dated: 1609–1436 cal. BCE). Although a very recent study proposes an oriental origin of this haplotype (14), we cannot determine the geographical origin of Y-HT-1 with certainty, because this haplotype has not been found thus far in predomestic or wild stallions. There are two possible scenarios: (i) Y-HT-1 emerged within the domestic population by mutation and (ii) Y-HT-1 was already present in wild horses and entered the domestic population either at the beginning of domestication (but initially restricted to Asian horses) or later by introgression (from wild Y-HT-1 carrying studs during the Iron Age). Crosses between domestic animals and their wild counterparts have been observed in several domestic species (15–18); thus, the simplest explanation would be that we missed Y-HT-1 in older samples because of limited geographical sampling. However, the estimated haplotype age is contemporary (Fig. 4) with the assumed starting point of horse domestication ~4000–3500 BCE (19), rendering it likely that Y-HT-1 originated within the domestic horse gene pool. Still, we cannot rule out definitively that it appeared before domestication.

Independent of its geographical origin, Y-HT-1 progressively replaced all other haplotypes—except for one additional lineage that is restricted to Yakutian horses (11). Considering our data, this trend in paternal diversity toward dominance of the modern lineage appears to start in the Bronze Age and becomes even more pronounced during the Iron Age. The Bronze Age was a time of large-scale human migrations across Eurasia (20–22), movements that were undoubtedly facilitated by the spread of horses as a means of transport and warfare. At that time, the western Eurasian steppes were inhabited by highly mobile cultures that largely relied on horses (20, 21, 23, 24). The genetic admixture of northern and central European humans with Caucasians/eastern Europeans did correlate with the spread of the Yamnaya culture from the Pontic-Caspian steppe (25), an area that has repeatedly been suggested as the center of horse domestication (19, 26, 27). Given the importance of domestic horses, it appears that deliberate selection/rejection of certain stallions by these people might have contributed to the loss of paternal diversity. The spread of humans out of this region might also have resulted in the spread of Y-HT-1 from Asia to Europe. This scenario also agrees with recent findings that the low male diversity of extant horses is not caused by recruiting only a limited number of stallions during early domestication (13).

horses-y-chromosome-map
Decline of paternal diversity began in Asia.
Maps displaying age, locality, and haplotype (different colors) of each successfully genotyped sample.

The presence of the Y chromosome haplotype carried by present-day Przewalski horses (Y-HT-2) in early domestic stallions and a European wild horse (Pie05; table S2) could be the result of introgression of Przewalski stallions. Although the original distribution of the Przewalski horse is unknown, it was probably much larger than that of the relict population in Mongolia that produced modern Przewalski horses and might even have extended into Central Europe. However, it is also possible that either Przewalski horses were among the initially domesticated horses or that Y-HT-2 occurred both in Przewalski horses and in those wild horses that are the ancestors of domestic horses, based on autosomal DNA data (30). Regardless of how Y-HT-2 entered the domestic gene pool, it was eventually lost, as were all haplotypes except Y-HT-1. In our sample set, Y-HT-2 was undetectable as early as the third time bin. However, it is possible that Y-HT-2 may have been present during this time period, but with a frequency below 0.11 (with 95% probability). The inferred time trajectories for Y-HT-2 frequencies suggest that it could nevertheless have persisted at very low frequencies until the Middle Ages (Fig. 3). On the basis of these simulations, this finding could be interpreted as a relic of this haplotype’s formerly higher frequency in the domestic horse gene pool. It is also possible that the presence of this haplotype could be the result of mating a wild stallion with a domestic mare, a frequently reported breeding practice when wild horses were still widely distributed. However, a significant contribution of the Przewalski horse to the gene pool of modern domestic horses has been almost ruled out by recent genomic studies (13, 31, 32).

horses-y-chromosome-selection
Stallion lineages through time.
Temporal haplotype network of the four detected Y chromosome haplotypes. Age of the samples indicated by multiple layers separated by color; vertical lines connecting the haplotypes of consecutive layers/ages represent which haplotype was transferred into a later/younger period. Numbers constitute the respective number of individuals showing this particular haplotype for that period. Prz, Przewalski; Dom, domestic.

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