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Post by Admin on Apr 24, 2023 18:57:22 GMT
The Xiongnu Empire, from 300BC, had a significant impact on the political economies of Central, Inner and East Asia and created extensive trade networks. The world’s first nomadic empire – which battled imperial China for centuries – was very genetically diverse and not the “simple body” of people that its Han Chinese rivals long claimed, according to a new study of ancient DNA. The nomads, known as the Xiongnu, also had prominent roles for women, the researchers said in a paper published in the peer-reviewed journal Science Advances on April 15. The Xiongnu Empire was centred in Mongolia and for nearly three centuries from 200BC controlled the eastern Eurasian steppe that covered modern-day Mongolia, northern China, southern Siberia and Central Asia. Some historians have even suggested that the northern branch of the Xiongnu became the European Huns. Genetic population structure of the Xiongnu Empire at imperial and local scales Abstract The Xiongnu established the first nomadic imperial power, controlling the Eastern Eurasian steppe from ca. 200 BCE to 100 CE. Recent archaeogenetic studies identified extreme levels of genetic diversity across the empire, corroborating historical records of the Xiongnu Empire being multiethnic. However, it has remained unknown how this diversity was structured at the local community level or by sociopolitical status. To address this, we investigated aristocratic and local elite cemeteries at the western frontier of the empire. Analyzing genome-wide data from 18 individuals, we show that genetic diversity within these communities was comparable to the empire as a whole, and that high diversity was also observed within extended families. Genetic heterogeneity was highest among the lowest-status individuals, implying diverse origins, while higher-status individuals harbored less genetic diversity, suggesting that elite status and power was concentrated within specific subsets of the broader Xiongnu population. www.science.org/doi/10.1126/sciadv.adf3904
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Post by Admin on Apr 25, 2023 17:58:39 GMT
INTRODUCTION The Xiongnu Empire was the first of many historically documented steppe empires to arise in Eurasia, and its formation foreshadowed the rise of subsequent nomadic imperial powers, including the Mongol Empire, whose reach a millennium later stretched from the East Sea to the Carpathian Mountains (1). Centered on the territory of present-day Mongolia, the Xiongnu empire controlled the Eastern Eurasian Steppe and surrounding regions in northern China, southern Siberia, and Central Asia for nearly three centuries, starting from ca. 209 BCE until their eventual disintegration in the late first century CE. At its height, the Xiongnu profoundly influenced the political economies of Central, Inner, and East Asia, becoming a major political rival of imperial China and establishing far-flung trade networks that imported Roman glass, Persian textiles, Egyptian faience, Greek silver, and Chinese bronzes, silks, and lacquerware deep into the heart of their empire (2).
The Xiongnu represented a radically new kind of political entity that incorporated heterogeneous nomadic and sedentary groups spanning the Eastern Steppes and as far west as the Altai Mountains, under a single authority. As the Xiongnu expanded their empire from its core in central and eastern Mongolia, they conquered and integrated numerous neighboring groups. They successfully expanded into western Mongolia and southern areas of Lake Baikal, while winning decisive victories in northern China (3). However, the Xiongnu were much more than just experts in mobilizing cavalry forces for conquests. They were also shrewd trade partners who exerted considerable influence over the Silk Road kingdoms of Central Asia (4), with even greater control over Eurasian exchange networks during the late Xiongnu period (ca. 50 BCE to 100 CE). Nevertheless, a detailed understanding of their internal social and political organization is lacking (5).
Historical narratives of the Xiongnu were largely authored by their Han Chinese political rivals, who repeatedly and dismissively characterized their polity as a “simple body” of nomadic elites (3, 6). Much of what is now known about Xiongnu sociopolitical organization has been gleaned from textual evidence alongside a growing body of archaeological sites throughout Inner Asia, consisting primarily of cemeteries (2, 7–9). The mortuary record indicates that there is a sociopolitical hierarchy among the Xiongnu, with clear differences between individuals in terms of burial type, investment in construction, and offerings. Most identified graves of the late Xiongnu period are shaft pits set beneath thick stone rings on the surface. These conspicuous burials represent the vast network of regional and local elites of Xiongnu society, while commoners were likely buried under less conspicuous stone piles or in unmarked pits (10). The uppermost aristocratic ruling elites of the empire were buried in large square stone tombs, often flanked by satellite burials of lower-status individuals, forming a mortuary complex (11). Elites in square tombs and large circular graves were richly buried, typically in decorated wood-plank coffins and accompanied by foreign luxury goods, gold, or gilt objects, and sacrifices of horses and other valuable livestock. Metal discs and crescents representing the sun and moon, a symbol of the Xiongnu empire, are also frequently found in such elite graves. Because of their wealth and conspicuous appearance on the landscape, many Xiongnu graves have been looted since antiquity, but the differences in grave forms nevertheless reflect clear social gradations, with the square tombs as an exclusive political faction within the empire (2).
Previous archaeogenetics studies have sought to identify the people who made up the Xiongnu and have found an extremely high level of genetic diversity across the Xiongnu empire (12–16). Recently, a genome-wide study of 60 individuals from 27 Xiongnu sites found that this diversity was initially formed by the unification of two genetically distinct pastoralist populations in Mongolia—one descending from groups associated with the Deerstone Khirigsuur, Mönkhkhairkhan, and Sagly/Uyuk cultures in the west and the other the descendants of the Ulaanzuukh and Slab Grave cultures in the east—followed by additional population influx from other regions, most likely Sarmatia (near present-day Ukraine) and imperial China (14). However, while this evidence supports previous claims that the Xiongnu Empire was likely a multiethnic, multicultural, and multilingual entity, until now, it has not been possible to determine whether such diversity was composed of a heterogeneous patchwork of locally homogenous communities or whether local communities themselves were also internally diverse. Moreover, many aspects of Xiongnu political constituencies still remain unknown, such as who made up the imperial elite occupants of the square tombs, and what their relationship was to lower-status individuals, including those buried in satellite graves within their elaborate tomb complexes. It also remains unclear whether high-status square tomb elites and local elites in the standard circular graves were drawn from the same segments of the Xiongnu population, or whether local elites were more likely to genetically resemble prior local populations than their incoming imperial counterparts, which would suggest that demographic processes associated with empire formation may have been stratified by status and origin.
To address these questions, here, we genetically investigate in detail a range of burials from the aristocratic elite cemetery of Takhiltyn Khotgor (TAK) and the local elite cemetery of Shombuuzyn Belchir (SBB), located at the far western frontier of the empire in Mongolia’s present-day Khovd province. Analyzing the genome-wide data of 18 individuals from high and low-status burials, we show that both communities harbored an extremely high level of genetic diversity that is comparable to that of the Xiongnu Empire as a whole. High genetic diversity is reflected within individual tomb complexes and burial clusters and even extended family groups. Thus, we find that the same sociopolitical processes that produced a genetically diverse empire on a vast scale also operated at the smallest scale, creating highly diverse local communities over the span of only a few generations. There are also discernable genetic patterns with respect to social and political status at TAK and SBB, where individuals of the lowest status (based on grave form and mortuary remains) have the highest degree of genetic heterogeneity. In contrast, higher-status individuals are less genetically diverse and have high levels of eastern Eurasian ancestry. This further suggests the existence of an aristocracy in the Xiongnu empire, that elite status and power was concentrated within specific subsets of the broader population.
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Post by Admin on Apr 26, 2023 17:40:40 GMT
RESULTS Generation of genome-wide data from Xiongnu aristocratic elites, local elites, and subordinates Before this study, two archaeogenetic studies had intensively investigated Xiongnu-era cemeteries in the political core of the Xiongnu empire at Egyin Gol (12) and Tamir Ulaan Khoshuu (16), but these studies did not generate genome-wide data and thus they have limited capacity to trace individual ancestries and relationships. Other studies have focused on producing genome-wide datasets (13–15), but the small number of individuals they analyzed per site make these data insufficient to explore genetic diversity within Xiongnu communities or potential associations with sociopolitical status. To address this, we conducted an intensive genome-wide archaeogenetic investigation of two Xiongnu cemeteries, the aristocratic elite cemetery of TAK and the local elite cemetery of SBB, which are located at the far western frontier of the Xiongnu empire in the Altai mountains. These cemeteries include the full social spectrum of individuals from exclusive square tombs to standard circular graves to meager pit graves. This dataset helps to better understand the genetic diversity, heterogeneity, and relationships among elites and subordinates at Xiongnu communities in the social and spatial edges of their empire. We then compared these frontier Xiongnu communities to previously published archaeogenomic data for 29 additional Xiongnu sites across Mongolia (Fig. 1A) (13, 14). Fig. 1. Map of Xiongnu sites in this study, and burial plans of the TAK and SBB cemeteries. (A) Geographic locations of the sites analyzed in the study are presented with the cultural affiliation and the time period. Newly sequenced individuals were excavated from the aristocratic elite cemetery of Takhiltyn Khotgor (TAK) (yellow square) and the local elite cemetery of Shombuuzyn Belchir (SBB) (red circle) in western Mongolia. Previously reported Xiongnu sites with five or more sequenced individuals are also labeled in the figure: Salkhityn Am (SKT), Uguumur Uul (UGU), and the Il’movaya Pad (IMA) (14). Other Xiongnu sites are indicated with white diamonds (early Xiongnu) or black diamonds (late Xiongnu). Sites of the preceding Early Iron Age (EIA) associated with the Sagly/Uyuk (pink triangle) and Slab Grave (green down-pointing triangle) archaeological cultures are also shown. (B) Plan detail of the TAK cemetery indicating the square tomb complexes and associated graves (yellow). See fig. S1 for a full cemetery plan. (C) Plan of the SBB cemetery indicating stone circle and stone pile graves. Excavation focused on a dense grave cluster (pink) and a selection of other representative graves (red). See fig. S2 for a full cemetery plan. For both sites, tomb or grave numbers are indicated in bold red; each analyzed individual is numbered in black. The aristocratic cemetery of TAK, dating to ca. 40 BCE to 50 CE (17, 18), is notable not only for its large circular graves of local elites but also for its numerous square tombs (Fig. 1B and fig. S1), which were reserved for individuals of the highest status within the imperial Xiongnu hierarchy. Flanking many of these tombs are low-status “commoner” graves consisting of simple stone piles over stone cist or earthen pit burials. Together, these square tombs and satellite graves form extended mortuary complexes. At TAK, two complete square tomb mortuary complexes have been excavated, THL-82 and THL-64, and a third complex, THL-25, has been partly excavated (fig. S1). THL-82 consists of a large central elite square tomb flanked by two satellite graves to its east and west (Fig. 1B). The tomb contained the remains of an adult female, TAK001, who was buried in a decorated wood-plank coffin with six horses, Chinese bronze chariot pieces, and a bronze spouted pot (19). The use of a wood-plank coffin, in strict adherence with elite Xiongnu political culture and rituals, is particularly noteworthy in this frontier context, as the large larch wood planks must have been imported at great effort and expense into this largely treeless mountain region (20). The satellite graves each contained an adult male interred in an earthen pit burial (TAK008 and TAK009), one of whom (TAK008) was interred in a prone (face-down) position, which differs from the supine (face-up) position that is more typical of Xiongnu burials. THL-64 consisted of a large central elite square tomb with two satellite graves on its eastern side (Fig. 1B). Like THL-82, the tomb also contained the remains of an adult female, TAK002, who was buried in a wood-plank coffin with one horse, four caprines (either sheep or goat), and a golden disc and crescent, representing the sun and moon (17). The satellite graves each contained an adolescent male (TAK003 and TAK004) buried in simple stone cists in a semi-flexed position, a position consistent with long-standing local mortuary traditions in western Mongolia (21). Tomb complex THL-25, for which only the satellite graves have been excavated to date, consisted of a large central square tomb flanked by three satellite graves on its eastern side (Fig. 1B). The three satellite graves consisted of simple earthen pit burials, marked only by small piles of stones, containing the remains of a child (TAK005) and two adult males (TAK006 and TAK007). In total, we genetically investigated eight individuals from TAK cemetery, seven new to this study and one (TAK001) published in a previous study (14). Located approximately 50 km to the southwest of TAK, the local elite cemetery of SBB is situated along a strategic high mountain pass and spans a period from ca. 50 BCE to 210 CE (18, 20). Consistent with other local elite Xiongnu cemeteries, it consists primarily of circular graves containing the remains of both adult females and males, as well as children (data file S1A). Fifteen of the 33 graves have been excavated to date, of which 11 were genetically screened in this study and 10 of 11 were sufficiently preserved for genome-wide analysis (Fig. 1C and fig. S2). The analyzed individuals span the full spectrum of marked social status, from individuals in large stone-encircled graves with decorated wood-plank coffins and elaborate grave goods to humble burials consisting of small stone cists (fig. S2). Five of the analyzed graves were arranged into a cluster (graves 12, 13, 14, 15, and 18), while the others were spatially dispersed and selected as a representative sample of the remainder of the cemetery (graves 2, 7, 8, 19, 26, and 29). Graves 7, 8, 15, and 19 were the highest-status graves analyzed in this study, and each consisted of an adult female buried in a wood-plank coffin surrounded by a stone ring. Grave 7 contained the remains of an older adult female (SBB002) buried with a disassembled wooden cart, a bronze cauldron, a ceramic cooking pot, and a golden sun disc and moon crescent nailed to the wood-plank coffin. Grave 8 contained the remains of an older adult female (SBB003) buried in a quatrefoil-decorated coffin and interred with gilded glass beads and a Chinese mirror fragment, as well as a large deposit of livestock offerings consisting of at least 12 caprines (sheep or goats). Grave 15 contained the remains of an adult female (SBB007) buried in a decorated wood-plank coffin overlain with wooden cart pieces, as well as horse-riding tack, a gilded iron belt clasp, and a Han Dynasty–painted lacquer cup. Grave 19 contained the remains of a young adult female (SBB008) who had apparently died in childbirth; she was buried alongside an infant and wore a paste-bead necklace containing a faience bead depicting the phallus of Bes, an Egyptian god associated with the protection of children. Like SBB003, this woman was also buried with Chinese mirror fragments. The remaining graves were simpler, consisting of a small stone circle or stone pile overlying a stone cist. Grave 13 contained the remains of a middle-aged adult male (SBB001) buried with a bow, arrows, and spear. An adolescent (SBB011) buried in grave 12 was also buried with a bow, arrows, and spear, and a child (SBB009) buried in grave 26 was buried with a child-sized bow. Three additional children were buried in graves 14 (SBB005), 18 (SBB006), and 29 (SBB004), and grave goods consisted of varied glass beads in graves 14 and 18, while the child in grave 29 was buried with silk, leather, and felt. Last, grave 2 (SBB010) contained the remains of an older adult male buried with an iron sun disc and moon crescent. Screening of burial sediments recovered traces of silk clothing in all SBB burials. For this study, we generated new genome-wide data for 19 individuals from TAK and SBB, of which 17 yielded sufficient human DNA for analysis (>0.1% human DNA), and we further enriched these DNA libraries for a panel (“1240K”) of 1,233,013 ancestry-informative single-nucleotide polymorphisms (SNPs) using an in-solution DNA capture method (22). After enrichment and sequencing, between 11,950 and 659,982 SNPs were successfully covered by at least one high-quality read for each individual (data file S1A). For six individuals with endogenous DNA preservation in excess of 30% (SBB003, SBB007, SBB010, TAK002, TAK006, and TAK008), we also produced whole-genome shotgun sequencing data to 0.7 to 2.5× coverage (data file S1A). All libraries exhibited characteristic patterns of ancient DNA damage, including short fragment lengths and cytosine deamination at fragment ends. Genetic sex was determined for all 17 individuals (data file S1A), and all individuals exhibited low contamination (<6%; data file S1A), as estimated using mitochondrial DNA for all individuals (23) and the X chromosome for 10 males (24). For downstream population genetic analyses, we performed pseudo-haploid genotype calling (https://github.com/stschiff/sequenceTools; v1.5.2 last accessed at 25 April 2022) and concatenated our new genotype data with previously published genotype data for TAK001 (14) and other ancient (13–15, 22, 25–58) and present-day (25, 29, 59–63) individuals (data file S1B). We also attempted to assign uniparental haplogroups to each individual and successfully determined the mitochondrial haplogroup for 17 individuals and the Y-chromosome haplogroup for 6 of 10 males (data file S1A). We estimated genetic relatedness among individuals from TAK, SBB, and previously reported sites (14). Two pairs of genetic relatives were identified at the SBB site: one pair of second-degree relatives (SBB005-SBB007) and a pair of second-degree or more distant relatives (SBB001-SBB005; data file S1E).
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Post by Admin on Apr 27, 2023 18:51:27 GMT
Modeling Xiongnu ancestry Before proceeding to a more granular genetic analysis of the TAK and SBB sites, and of the Xiongnu population more generally, we first refined and updated our modeling of Xiongnu ancestry to incorporate newly available genome-wide data from the preceding Late Bronze Age (LBA) and Early Iron Age (EIA) periods in central and eastern Mongolia (15). In a previous study, we modeled individuals of the early Xiongnu period as a mixture of two distinct genetic groups present in Mongolia during the EIA (ca. 900 to 300 BCE): “Chandman_IA” and “SlabGrave.” Chandman_IA was representative of people in far western Mongolia associated with Sagly/Uyuk (ca. 500 to 200 BCE), Saka (ca. 900 to 200 BCE), and Pazyryk (ca. 500 to 200 BCE) groups in Siberia and Kazakhstan. “SlabGrave” was representative of people in eastern and central Mongolia associated with Slab Grave (ca. 1000 to 300 BCE) mortuary sites (14). Likely arising out of the LBA Ulaanzuukh archaeological culture (ca. 1450 to 1150 BCE) in eastern Mongolia, Slab Grave groups expanded into central and northern Mongolia as far north as the Lake Baikal region (7, 14, 64). Overall, individuals from the Ulaanzuukh and the Slab Grave cultures present a homogeneous genetic profile that has deep roots in the region and is referred to as Ancient Northeast Asian (ANA) (14). The recent publication of additional genome-wide data for Ulaanzuukh and Slab Grave individuals (15) provided an opportunity to investigate the genetic profile of the Slab Grave individuals across a wider geographical distribution (Fig. 1A) and to refine our genetic modeling of the formation of the Xiongnu more generally. We updated our admixture modeling of Ulaanzuukh and Slab Grave individuals using the qpAdm program (25). Fig. 2. qpAdm modeling of TAK and SBB individuals. The genetic profiles of ancient individuals are modeled as the mixture of two or three populations. The ancestry proportion of each source population is represented by the size of the box on the x axis. Horizontal bars represent ±1 SE estimated by qpAdm using 5-cM block jackknifing. Detailed results are presented in data file S2. (A) Ulaanzuukh and SlabGrave individuals are modeled as the mixture between Ancient Northeast Asian (ANA), represented by eastMongolia_preBA in this study, and Khovsgol_LBA. We modeled Takhiltyn Khotgor (TAK) (B) and Shombuuzyn Belchir (SBB) (C) individuals as the mixture of the preceding groups from Mongolia and the surrounding regions: SlabGrave1, Chandman_IA, Han_2000BP, Gonur1_BA, earlyXiongnu_west, Khovsgol_LBA, and UKY. We present two models for TAK008 and TAK009 First, we detected a subtle genetic shift in eastern Mongolia between the preceding pre–Bronze Age period and LBA Ulaanzuukh individuals (n = 13) (Fig. 2A, fig. S3; and data file S2A). We model this difference as gene flow from a nearby LBA population in northern Mongolia, such as that found in the northernmost province of Khovsgol (“Khovsgol_LBA”). Collectively, Ulaanzuukh individuals are adequately modeled as having a 24.5% contribution from Khovsgol_LBA (P = 0.550; data file S2A), and at an individual level most also fit the same model with 13.9 to 33.4% contributions from Khovsgol_LBA (data file S2A), with the exception of one individual with an unusually high Khovsgol_LBA contribution (ULN005; 63.5%). On the basis of the admixture modeling results, we grouped 12 of 13 Ulaanzuukh individuals as an analysis unit (“Ulaanzuukh1”), excluding ULN005 for its much higher Khovsgol_LBA affinity (separately analyzed as “Ulaanzuukh2”), and used it as a representative of the Ulaanzuukh gene pool. To better understand the genetic make-up of Iron Age Slab Grave individuals (n = 16), we compared their genetic profiles with the preceding Ulaanzuukh individuals. Incorporating data from 11 newly published individuals (15), we identified a subtle genetic heterogeneity not detected in our previous study (14). While 13 of 16 individuals are cladal with Ulaanzuukh1, the remaining 3 individuals require additional Khovsgol_LBA ancestry (Fig. 2, fig. S3, and data file S2B). In particular, Slab Grave individuals I6359, I6369, and DAR001 are markedly distinct from the others by carrying high proportions of Khovsgol_LBA ancestry (42.6 to 79.7%) (data file S2B). This pattern, in which most Slab Grave individuals are genetically homogeneous while some have a large and heterogeneous ancestry fraction deriving from a Khovsgol_LBA-like gene pool, is likely due to population mixing in their recent past and is consistent with archaeological evidence that the Slab Grave culture expanded into central and northern Mongolia and replaced the preceding inhabitants in the region with a low level of mixing (65). On the basis of individual ancestry modeling, we assigned most of the Slab Grave individuals (13 of 16) into a single group “SlabGrave1,” while we assigned the remaining three individuals with high Khovsgol_LBA ancestry into another group, “SlabGrave2,” for their use in the downstream group-based analyses. To characterize the genetic profiles of our new Xiongnu-period individuals, we modeled the ancestry composition of the TAK and SBB individuals using qpAdm (Fig. 2). Most individuals (15 of 18) are adequately modeled by the admixture models previously applied to Xiongnu individuals, which used Ulaanzuukh/SlabGrave and Han_2000BP as eastern Eurasian sources (data file S2C) (14). Eight of these 15 individuals are adequately modeled with two ancestries, SlabGrave1 and Chandman_IA: Five are mixed between SlabGrave1 and Chandman_IA (SBB001, SBB002, SBB006, SBB008, and SBB009; 32 to 91% from SlabGrave1), one is indistinguishable from Chandman_IA (TAK005), and two are indistinguishable from SlabGrave1 (SBB004 and TAK004). A further five individuals are modeled using an additional East Asian ancestry distinct from ANA, here represented by Han_2000BP (14): Three are modeled as a mixture of SlabGrave1, Chandman_IA, and Han_2000BP (SBB003, SBB005, and SBB007; 28 to 77% from SlabGrave1, 11 to 52% from Chandman_IA, and 12 to 19% from Han_2000BP), and two are modeled as a mixture of SlabGrave1 and Han_2000BP (TAK002 and TAK006; 48 to 74% from SlabGrave1 and 26 to 52% from Han_2000BP). Last, two individuals require an Iranian/Central Asian ancestry represented by Gonur1_BA (26): One is modeled as the mixture of SlabGrave1, Chandman_IA, and Gonur1_BA (SBB010; 39% from SlabGrave1, 48% from Chandman_IA, and 13% from Gonur1_BA), and the other as the mixture of Chandman_IA and Gonur1_BA (TAK003; 28% from Gonur1_BA). TAK003 has a higher Gonur1_BA-related ancestry proportion than previously described early Xiongnu individuals with the same ancestry combination (“earlyXiongnu_west”), corroborating a previous report of continued gene flow from Central Asia between the early and late Xiongnu periods (14). We note that all qpAdm admixture models equally fit when SlabGrave1 was replaced by “AR_Xianbei_IA” from the Mogushan archaeological site in Inner Mongolia that belongs to the Iron Age Xianbei context (data file S2C) (27). All but two males (BUL002 and I6365) associated with the Ulaanzuukh and Slab Grave cultures belong to Y-haplogroup Q, all three AR_Xianbei_IA males belong to Y-haplogroup C, and the Xiongnu males harbor both Q and C (data file S1C) (14, 15). Although not conclusive, this suggests that the ANA ancestry source of the Xiongnu-period individuals may not be exclusively traced back to the Slab Grave culture but may also include nearby groups with a similar ANA genetic profile, such as the Xianbei. The remaining 3 of 18 individuals are excavated from the same mortuary complex, THL-82, and require a distinct eastern Eurasian ancestral component. Two individuals from satellite graves, TAK008 and TAK009, have a high proportion of western Eurasian ancestry but are not modeled as a sister clade with either Chandman_IA or earlyXiongnu_west (qpWave P = 1.98 × 10−7 for Chandman_IA and qpWave P = 2.42 × 10−3 for earlyXiongnu_west). We then compared their genetic profile with earlyXiongnu_west by calculating f4(Mbuti, world-wide; TAK008/TAK009, earlyXiongnu_west) for a set of world-wide ancient and present-day populations. While there is no population showing significant extra affinity with earlyXiongnu_west, several populations show extra affinity with TAK008/TAK009. For TAK009, the top signals are mostly ancient individuals/populations from East Asia (fig. S4). In line with this, we adequately model TAK009 as a mixture of earlyXiongnu_west and various East Asian populations, including Khovsgol_LBA, SlabGrave1, and Han_2000BP (data file S2C). For TAK008, we observe an overall similar trend but find populations with high Ancient North Eurasian (ANE) affinity, such as the Upper Paleolithic individual from the Ust-Kyakhta-3 site (UKY) (28) and present-day Native Americans (Mixe and Quechua), among the top signals (fig. S4). Consistent with this, TAK008 is adequately modeled with ~10% contribution from Khovsgol_LBA or UKY, but not with other East Asian proxies with no ANE affinity, such as SlabGrave1 or Han_2000BP (data file S2C). TAK001, a previously published female from a square tomb (14), is well explained by the same model with TAK008 and TAK009 but with different admixture proportions. TAK001 derives 90.7% of her ancestry from Khovsgol_LBA and the rest from earlyXiongnu_west. It is rather unexpected to observe the presence of Khovsgol_LBA ancestry in a form not associated with SlabGrave ancestry during the Xiongnu period, as it had largely been replaced by Slab Grave in Mongolia by the EIA (14). Khovsgol_LBA ancestry was also reported from the Mongol era site Khalzan Khoshuu, which is located only 95 km away from the TAK site (14). Further sampling is required to understand the spatial and temporal distribution of Khovsgol_LBA ancestry after the LBA, especially in the Altai region.
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Post by Admin on May 7, 2023 18:31:04 GMT
High genetic diversity within Xiongnu communities and across the empire To examine spatial patterns of Xiongnu genetic diversity at TAK and SBB, as well as across their empire as a whole, we performed principal components analysis (PCA) (Fig. 3) following the approach described by (66), projecting ancient individuals onto the genotype dataset of present-day individuals genotyped on the Affymetrix Axiom Genome-Wide Human Origins 1 (“HO”) array (data file S1B) (59). All new Xiongnu individuals fall within the diverse range of genetic profiles previously reported for the Xiongnu (14) and are widely scattered along PC1 between western and eastern Eurasians. This pattern indicates that the marked genetic heterogeneity observed for the Xiongnu as a whole was also present at sites along its western frontier, far from the imperial core. We next quantified the level of genetic heterogeneity within each site and compared it with the overall Xiongnu genetic diversity within Mongolia (Fig. 4). We used the PC1 coordinates of each individual as a primary variable of the analysis because PC1 captures the major axis of genetic variation within both the Xiongnu and Eurasians in general: High and low PC1 values represent high genetic affinity to eastern and western Eurasians, respectively. Fig. 3. Genetic diversity of the Xiongnu. (A) Principal components analysis (PCA) of Takhiltyn Khotgor (TAK) (yellow squares) and Shombuuzyn Belchir (SBB) (red circles) individuals. Other Xiongnu individuals are shown as hollow diamonds (early Xiongnu) and black diamonds (late Xiongnu). Ancient individuals were projected on the PCs calculated with 2077 present-day Eurasian individuals (gray). Inset shows PC1 on the x-axis and PC3 on the y axis. PC3 explains the 0.33% of the total variance. The x axis and y axis ticks have the same values across all panels, except the inset of (A) where the y axis ranges from −0.04 to 0.06. (B) PCA of Gol Mod 2 (azure squares) and other Xiongnu sites with five or more genetically analyzed individuals: Salkhityn Am (SKT) (purple squares), Uguumur Uul (blue circles), and Il’movaya Pad (IMA) (green circles). (C) PCA of the preceding Early Iron Age (EIA) Sagly/Uyuk (pink triangles) and Slab Grave (green down-pointing triangles) individuals. (D) PCA of TAK individuals, with color indicating tomb complex and size reflecting grave type. (E) PCA of SBB individuals, with color indicating cluster membership and size reflecting grave type. SBB005 is a second-degree genetic relative of SBB001 and SBB007. Fig. 4. Genetic diversity of the Xiongnu at local and imperial scales. Left presents PC1 coordinates for individuals at Takhiltyn Khotgor (TAK), Shombuuzyn Belchir (SBB), and three previously reported Xiongnu sites with five or more sequenced individuals (14). For comparison, we also display PC1 coordinates for Xiongnu, Chandman_IA, and SlabGrave individuals as three independent clusters. The color of the boxes indicates the time period: Early Iron, pink; early Xiongnu, dark gray; late Xiongnu, light gray; and entire Xiongnu, light blue. Newly reported sites (TAK and SBB) are marked by a surrounding box. The PC1 distribution of Xiongnu individuals as a whole exceeds that of the prior Early Iron Age (EIA). With the exception of Il’movaya Pad (IMA), the PC1 distribution of individuals within each Xiongnu site is broader than that of either Chandman_IA or SlabGrave, and the overall PC1 distribution of individuals at Xiongnu sites is generally high. This indicates that the high genetic diversity observed among the Xiongnu as a whole is also reflected within Xiongnu communities. On the right, we compare PC1 coordinates of TAK/SBB individuals according to their social status (high versus low). The color of the boxes indicates social status: green, high; yellow, low; and it matches the color of the dots on the left. The overall PC1 distribution of the high-class individuals is more restricted than that of the lower class individuals.
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