Peopling History of the Tibetan Plateau and Multiple Waves of Admixture of Tibetans Inferred From Both Ancient and Modern Genome-Wide Data

Pilot work of the 10K Chinese People Genomic Diversity Project along the Silk Road suggests a complex east-west admixture landscape and biological adaptations

Genomic sources from China are underrepresented in the population-specific reference database. We performed whole-genome sequencing or genome-wide genotyping on 1,207 individuals from four linguistically diverse groups (1,081 Sinitic, 56 Mongolic, 40 Turkic, and 30 Tibeto-Burman people) living in North China included in the 10K Chinese People Genomic Diversity Project (10K_CPGDP) to characterize the genetic architecture and adaptative history of ethnic groups in the Silk Road Region of China. We observed a population split between Northwest Chinese minorities (NWCMs) and Han Chinese since the Upper Paleolithic and later Neolithic genetic differentiation within NWCMs. The observed population substructures among ethnically/linguistically diverse NWCMs suggested that differentiated admixture events contributed to the differences in their genomic and phenotypic diversity. We estimated that the Dongxiang, Tibetan, and Yugur people inherited more than 10% of the Western Eurasian ancestry, which is much greater than that of the Salar and Tu people (<7%), while Han neighbors showed less West Eurasian ancestry (∼1%-3%). Male-biased admixture introduced Western Eurasian ancestry in the Dongxiang, Tibetan, and Yugur populations. We found that the eastern-western admixture in NWCMs occurred ∼800-1,100 years ago, coinciding with intensive economic and cultural exchanges during the Tang and Song dynasties. Additionally, we identified the signatures of natural selection associated with cardiovascular system diseases or lipid metabolism and developmental/neurogenetic disorders. Moreover, the EPAS1 gene showed relatively high population branch statistic values in NWCMs. The well-fitted demographical models presented the vast landscape of complex admixture processes of the Silk Road people, and the newly reported functionally important variations suggested the importance of including ethnolinguistically diverse populations in Chinese genetic studies for uncovering the genetic basis of complex traits/diseases.

YHSeqY3000 panel captures all founding lineages in the Chinese paternal genomic diversity database

BACKGROUND

The advancements in second-/third-generation sequencing technologies, alongside computational innovations, have significantly enhanced our understanding of the genomic structure of Y-chromosomes and their unique phylogenetic characteristics. These researches, despite the challenges posed by the lack of population-scale genomic databases, have the potential to revolutionize our approach to high-resolution, population-specific Y-chromosome panels and databases for anthropological and forensic applications.

OBJECTIVES

This study aimed to develop the highest-resolution Y-targeted sequencing panel, utilizing time-stamped, core phylogenetic informative mutations identified from high-coverage sequences in the YanHuang cohort. This panel is intended to provide a new tool for forensic complex pedigree search and paternal biogeographical ancestry inference, as well as explore the general patterns of the fine-scale paternal evolutionary history of ethnolinguistically diverse Chinese populations.

RESULTS

The sequencing performance of the East Asian-specific Y-chromosomal panel, including 2999-core SNP variants, was found to be robust and reliable. The YHSeqY3000 panel was designed to capture the genetic diversity of Chinese paternal lineages from 3500 years ago, identifying 408 terminal lineages in 2097 individuals across 41 genetically and geographically distinct populations. We identified a fine-scale paternal substructure that was correlating with ancient population migrations and expansions. New evidence was provided for extensive gene flow events between minority ethnic groups and Han Chinese people, based on the integrative Chinese Paternal Genomic Diversity Database.

CONCLUSIONS

This work successfully integrated Y-chromosome-related basic genomic science with forensic and anthropological translational applications, emphasizing the necessity of comprehensively characterizing Y-chromosome genomic diversity from genomically under-representative populations. This is particularly important in the second phase of our population-specific medical or anthropological genomic cohorts, where dense sampling strategies are employed.

Dissecting the genetic admixture and forensic signatures of ethnolinguistically diverse Chinese populations via a 114-plex NGS InDel panel

Comprehensive characterizations of genetic diversity and demographic models of ethnolinguistically diverse Chinese populations are essential for elucidating their forensic characteristics and evolutionary past. We developed a 114-plex NGS InDel panel to genotype 114 genome-wide markers and investigated the genetic structures of Zhuang, Hui, Miao, Li, Tibetan, Yi, and Mongolian populations, encompassing five language families. This panel demonstrated robust performance, with exceptional potential for forensic individual identification and paternity testing, evidenced by the combined power of discrimination for 77 autosomal InDels (ranged from 1-3.6400 × 10-30 to 1-3.5713 × 10-32) and the combined power of exclusion (ranged from 1-2.1863 × 10-6 to 1-2.1261 × 10-7). The cumulative mean exclusion chance for 32 X-chromosomal InDels varied between 0.99996 and 0.99999 for trios and 0.99760 to 0.99898 for duos. We also analyzed genetic similarities and differences between these populations and 27 global populations, revealing distinct clusters among African, South Asian, East Asian, and European groups, with a close genetic affinity to East Asians. Notably, we identified geography-related genetic substructures: Inner Mongolia Mongolians and Gansu Huis formed a northern branch, Tibetans and Yis from Sichuan constituted a highland branch, and Guangxi Zhuangs exhibited close ties with Hainan Lis and Guangxi Miaos in the southern branch. Additionally, many InDels proved to be ancestry-informative markers for biogeographic ancestry inference. Collectively, these findings underscore the utility of the 114-plex NGS InDel panel as a complementary tool for forensic investigations and as a source of insights into the genetic architecture of ethnolinguistically distinct Chinese populations.

Screening of functional genes for hypoxia adaptation in Tibetan pigs by combined genome resequencing and transcriptome analysis

The high-altitude, low-oxygen environment of the Qinghai-Tibet Plateau poses significant challenges for the introduction of superior livestock breeds. However, local plateau species have adapted to thrive and reproduce under these harsh conditions. Understanding the molecular mechanisms behind plateau animals' adaptation to low-oxygen environments is essential for breeding livestock suited to high-altitude regions. Tibetan pigs, which have undergone long-term natural selection and artificial breeding, have developed the ability to survive and reproduce in hypoxic environments. In this study, we conducted whole-genome resequencing of 30 Tibetan pigs from high-altitude regions and 30 Diannan small-ear pigs from low-altitude areas, to identify candidate genes that support Tibetan pigs' adaptation to hypoxic conditions through selection signal analysis. Additionally, we performed transcriptome sequencing on five tissues (heart, liver, spleen, lung, and bone marrow) from both Tibetan pigs and Diannan small-ear pigs to identify genes with significant differential expression between the two breeds. We then integrated the genomic and transcriptomic data by examining the expression of candidate genes identified in selection signal analysis across different tissues. The selection signal analysis identified 10 genes-HES4, ANGPT1, HIF3A, SPHK2, PCK2, RCN3, HIGD2A, DNM2, IRF9, and SRF-that were under positive selection in the Tibetan pig population and are associated with hypoxia adaptation. When combined with transcriptome data, we found that five of these genes-HIF3A, RCN3, HIGD2A, PCK2, and IRF9-exhibited differential expression. Through an integrated approach of selection signal and transcriptome analysis, we identified five key functional genes that contribute to the adaptation of Tibetan pigs to hypoxic environments. These findings offer new insights into the adaptability of plateau animals.

Genetic history and biological adaptive landscape of the Tujia people inferred from shared haplotypes and alleles

BACKGROUND

High-quality genomic datasets from under-representative populations are essential for population genetic analysis and medical relevance. Although the Tujia are the most populous ethnic minority in southwestern China, previous genetic studies have been fragmented and only partially reveal their genetic diversity landscape. The understanding of their fine-scale genetic structure and potentially differentiated biological adaptive features remains nascent.

OBJECTIVES

This study aims to explore the demographic history and genetic architecture related to the natural selection of the Tujia people, focusing on a meta-Tujia population from the central regions of the Yangtze River Basin.

RESULTS

Population genetic analyses conducted on the meta-Tujia people indicate that they occupy an intermediate position in the East Asian North-South genetic cline. A close genetic affinity was identified between the Tujia people and neighboring Sinitic-speaking populations. Admixture models suggest that the Tujia can be modeled as a mixture of northern and southern ancestries. Estimates of f3/f4 statistics confirmed the presence of ancestral links to ancient Yellow River Basin millet farmers and the BaBanQinCen-related groups. Furthermore, population-specific natural selection signatures were explored, revealing highly differentiated functional variants between the Tujia and southern indigenous populations, including genes associated with hair morphology (e.g., EDAR) and skin pigmentation (e.g., SLC24A5). Additionally, both shared and unique selection signatures were identified among ethnically diverse but geographically adjacent populations, highlighting their extensive admixture and the biological adaptations introduced by this admixture.

CONCLUSIONS

The study unveils significant population movements and genetic admixture among the Tujia and other ethno-linguistically diverse East Asian groups, elucidating the differentiated adaptation processes across geographically diverse populations from the current genetic landscape.

Distinguished biological adaptation architecture aggravated population differentiation of Tibeto-Burman-speaking people

Tibeto-Burman (TB) people have endeavored to adapt to the hypoxic, cold, and high-UV high-altitude environments in the Tibetan Plateau and complex disease exposures in lowland rainforests since the late Paleolithic period. However, the full landscape of genetic history and biological adaptation of geographically diverse TB-speaking people, as well as their interaction mechanism, remain unknown. Here, we generate a whole-genome meta-database of 500 individuals from 39 TB-speaking populations and present a comprehensive landscape of genetic diversity, admixture history, and differentiated adaptative features of geographically different TB-speaking people. We identify genetic differentiation related to geography and language among TB-speaking people, consistent with their differentiated admixture process with incoming or indigenous ancestral source populations. A robust genetic connection between the Tibetan-Yi corridor and the ancient Yellow River people supports their Northern China origin hypothesis. We finally report substructure-related differentiated biological adaptative signatures between highland Tibetans and Loloish speakers. Adaptative signatures associated with the physical pigmentation (EDAR and SLC24A5) and metabolism (ALDH9A1) are identified in Loloish people, which differed from the high-altitude adaptative genetic architecture in Tibetan. TB-related genomic resources provide new insights into the genetic basis of biological adaptation and better reference for the anthropologically informed sampling design in biomedical and genomic cohort research.

An Anthropometric Study of the Morphologic Facial Index of Tibetan Youth in Tibet

The purpose of this study was to understand sex differences and variations in facial indices among Tibetans and to create and evaluate anthropometric data on facial morphology. The study population consisted of 476 native Tibetans (241 males and 235 females) aged 18 to 24 years. The means and SD facial width was 133.53±7.31 mm for males and 133.95±8.10 mm for females; the difference between the sexes was not statistically significant. The means and SD facial height was 107.68±5.76 mm for males and 111.95±14.28 mm for females; the difference between the sexes was statistically significant (u=-8.394, P=0.000). The morphologic facial index was 80.86±5.82 (means±SD) for males and 83.91±11.90 (means±SD) for females; the difference between the sexes was statistically significant (u=-6.581, P=0.000). The proportion of the Tibetan male facial shape was hypereuryprosopic (45.6%) > euryprosopic (31.1%) > mesoprosopic (18.7%) > leptoprosopic (3.3%) > hyperleptoprosopic (1.2%). The proportion of the Tibetan female facial shape was hypereuryprosopic (25.5%) > mesoprosopic (22.6%) > euryprosopic (21.7%) > leptoprosopic (17.4%) > hyperleptoprosopic (12.8%). Facial width was positively correlated with height (male r=0.306, P=0.000; female r=0.144, P=0.027), weight (r=0.470, P=0.000 for males; r=0.337, P=0.000 for females), and BMI (r=0.378, P=0.000 for males; r=0.291, P=0.000 for females). Facial height was positively correlated with height (r=0.329, P=0.000 for males; r=0.137, P=0.035 for females) and weight (r=0.391, P=0.000 for males; r=0.170, P=0.009 for females). Facial height was positively correlated with BMI in Tibetan males (r=0.293, P=0.000), but no significant correlation was found in Tibetan females. The morphologic facial index of Tibetans was positively correlated with age (r=0.183, P=0.004 for males; r=0.171, P=0.009 for females). The results indicated that Tibetan youth in Tibet have a predominantly hypereuryprosopic facial shape and that facial features are related to age, height, and weight. Some common facial morphology features exist among the Tibet Tibetans, northeastern Indians, and Nepalese in the 3 different regions of the Sino-Tibetan language family. The data from this study provide basic information for the study of Tibetans in the fields of physical anthropology, forensic medicine, maxillofacial surgery, and plastic surgery.

Geospatial modelling of farmer-herder interactions maps cultural geography of Bronze and Iron Age Tibet, 3600-2200 BP

Tibetan cultures reflect deeply rooted, regional interactions and diverse subsistence practices across varied high-altitude environments of the Tibetan Plateau. Yet, it remains unclear how these cultural relationships and social interactions took shape through time and how they were influenced by ecologically oriented behavioral strategies (e.g. mobility) emerging in prehistory. Recent applications of network analysis provide novel tools to quantitatively measure shared forms of material culture, but there have been fewer attempts to couple social network analysis with fine-grained geospatial modelling of prehistoric human mobility in Tibet. In this study, we developed an integrated high-resolution geospatial model and network analysis that simulates and correlates subsistence-based mobility and ceramic-based cultural material connectivity across the Tibetan Plateau. Our analysis suggests that (1) ecologically driven patterns of subsistence-based mobility correspond geographically with Bronze and Iron Ages settlement patterns across the Tibetan Plateau; (2) diverse material interaction networks among communities within western and central Tibet and trans-Himalayan connectivity across the broader Inner Asian Mountain Corridor can be linked to modeled differences in regional networks of subsistence mobility. This research provides ecological and archaeological insights into how subsistence-oriented mobility and interaction may have shaped documented patterns of social and material connectivity among regional Bronze and Iron Age communities of the Tibetan Plateau, prompting a reconsideration of Tibet's long-term cultural geography.

A Tibetan group from Ngawa Tibetan and Qiang Autonomous Prefecture, southwest China, is rich in genetic polymorphisms at 36 autosomal STR loci and shares a complex genetic structure with other Chinese populations

The Tibetan people are ancient and populous, constituting the seventh-largest of the fifty-five ethnic minority groups in China. The Ngawa Tibetan and Qiang Autonomous Prefecture (NTQAP), situated on the border of northwest and southwest China, has its distinct group relationships. Short tandem repeat (STR) is extremely polymorphic and extensively used in the application of forensic medicine and population genetics. However, it is not clear the genetic information including linkage disequilibrium (LD) by 36 autosomal STR (A-STR) markers in the Tibetan group from NTQAP. The Tibetan population from NTQAP of southwest China was examined for 36 A-STR loci in the research. Every marker across the 36 A-STR loci was consistent with Hardy-Weinberg equilibrium (HWE). The results of the calculation revealed that the total discrimination power (TDP) is 1-2.2552 × 10-42 and the cumulative probability of exclusion (CPE) is 1-1.3031 × 10-16. Subsequently, a total of 345 alleles with allelic frequencies ranging from 0.00382 to 0.55343 were identified, and the allelic numbers varied from 5 in both the TH01 and TPOX markers to 28 in the SE33 locus. The Ngawa Tibetan population, along with other Chinese populations, exhibited influences from historical factors and regional distribution, as indicated by the results of population genetics analysis. We thus first explored the genetic characteristics and correlated forensic parameters of the 36 A-STR markers in NTQAP to fill the gap in the Tibetan population. It was discovered that these 36 autosomal STR markers supplemented forensic STR databases and offered extremely valuable polymorphisms for Chinese forensic applications, such as parentage testing and personal identification. Moreover, the study would contribute additional information regarding the substructure and diversity in the Chinese population.

Whole mitochondrial genome analysis in highland Tibetans: further matrilineal genetic structure exploration

Introduction: The Qinghai-Tibet Plateau is one of the last terrestrial environments conquered by modern humans. Tibetans are among the few high-altitude settlers in the world, and understanding the genetic profile of Tibetans plays a pivotal role in studies of anthropology, genetics, and archaeology. Methods: In this study, we investigated the maternal genetic landscape of Tibetans based on the whole mitochondrial genome collected from 145 unrelated native Lhasa Tibetans. Molecular diversity indices, haplotype diversity (HD), Tajima's D and Fu's Fs were calculated and the Bayesian Skyline Plot was obtained to determining the genetic profile and population fluctuation of Lhasa Tibetans. To further explore the genetic structure of Lhasa Tibetans, we collected 107 East Asian reference populations to perform principal component analysis (PCA), multidimensional scaling (MDS), calculated Fst values and constructed phylogenetic tree. Results: The maternal genetic landscape of Tibetans showed obvious East Asian characteristics, M9a (28.28%), R (11.03%), F1 (12.41%), D4 (9.66%), N (6.21%), and M62 (4.14%) were the dominant haplogroups. The results of PCA, MDS, Fst and phylogenetic tree were consistent: Lhasa Tibetans clustered with other highland Tibeto-Burman speakers, there was obvious genetic homogeneity of Tibetans in Xizang, and genetic similarity between Tibetans and northern Han people and geographically adjacent populations was found. In addition, specific maternal lineages of Tibetans also be determined in this study. Discussion: In general, this study further shed light on long-time matrilineal continuity on the Tibetan Plateau and the genetic connection between Tibetans and millet famers in the Yellow River Basin, and further revealed that multiple waves of population interaction and admixture during different historical periods between lowland and highland populations shaped the maternal genetic profile of Tibetans.

Genetic and cultural adaptations underlie the establishment of dairy pastoralism in the Tibetan Plateau

BACKGROUND

Domestication and introduction of dairy animals facilitated the permanent human occupation of the Tibetan Plateau. Yet the history of dairy pastoralism in the Tibetan Plateau remains poorly understood. Little is known how Tibetans adapted to milk and dairy products.

RESULTS

We integrated archeological evidence and genetic analysis to show the picture that the dairy ruminants, together with dogs, were introduced from West Eurasia into the Tibetan Plateau since ~ 3600 years ago. The genetic admixture between the exotic and indigenous dogs enriched the candidate lactase persistence (LP) allele 10974A > G of West Eurasian origin in Tibetan dogs. In vitro experiments demonstrate that - 13838G > A functions as a LP allele in Tibetans. Unlike multiple LP alleles presenting selective signatures in West Eurasians and South Asians, the de novo origin of Tibetan-specific LP allele - 13838G > A with low frequency (~ 6-7%) and absence of selection corresponds - 13910C > T in pastoralists across eastern Eurasia steppe.

CONCLUSIONS

Results depict a novel scenario of genetic and cultural adaptations to diet and expand current understanding of the establishment of dairy pastoralism in the Tibetan Plateau.

Multiple founding paternal lineages inferred from the newly-developed 639-plex Y-SNP panel suggested the complex admixture and migration history of Chinese people

BACKGROUND

Non-recombining regions of the Y-chromosome recorded the evolutionary traces of male human populations and are inherited haplotype-dependently and male-specifically. Recent whole Y-chromosome sequencing studies have identified previously unrecognized population divergence, expansion and admixture processes, which promotes a better understanding and application of the observed patterns of Y-chromosome genetic diversity.

RESULTS

Here, we developed one highest-resolution Y-chromosome single nucleotide polymorphism (Y-SNP) panel targeted for uniparental genealogy reconstruction and paternal biogeographical ancestry inference, which included 639 phylogenetically informative SNPs. We genotyped these loci in 1033 Chinese male individuals from 33 ethnolinguistically diverse populations and identified 256 terminal Y-chromosomal lineages with frequency ranging from 0.0010 (singleton) to 0.0687. We identified six dominant common founding lineages associated with different ethnolinguistic backgrounds, which included O2a2b1a1a1a1a1a1a1-M6539, O2a1b1a1a1a1a1a1-F17, O2a2b1a1a1a1a1b1a1b-MF15397, O2a2b2a1b1-A16609, O1b1a1a1a1b2a1a1-F2517, and O2a2b1a1a1a1a1a1-F155. The AMOVA and nucleotide diversity estimates revealed considerable differences and high genetic diversity among ethnolinguistically different populations. We constructed one representative phylogenetic tree among 33 studied populations based on the haplogroup frequency spectrum and sequence variations. Clustering patterns in principal component analysis and multidimensional scaling results showed a genetic differentiation between Tai-Kadai-speaking Li, Mongolic-speaking Mongolian, and other Sinitic-speaking Han Chinese populations. Phylogenetic topology inferred from the BEAST and Network relationships reconstructed from the popART further showed the founding lineages from culturally/linguistically diverse populations, such as C2a/C2b was dominant in Mongolian people and O1a/O1b was dominant in island Li people. We also identified many lineages shared by more than two ethnolinguistically different populations with a high proportion, suggesting their extensive admixture and migration history.

CONCLUSIONS

Our findings indicated that our developed high-resolution Y-SNP panel included major dominant Y-lineages of Chinese populations from different ethnic groups and geographical regions, which can be used as the primary and powerful tool for forensic practice. We should emphasize the necessity and importance of whole sequencing of more ethnolinguistically different populations, which can help identify more unrecognized population-specific variations for the promotion of Y-chromosome-based forensic applications.

Human genetic history on the Tibetan Plateau in the past 5100 years

Using genome-wide data of 89 ancient individuals dated to 5100 to 100 years before the present (B.P.) from 29 sites across the Tibetan Plateau, we found plateau-specific ancestry across plateau populations, with substantial genetic structure indicating high differentiation before 2500 B.P. Northeastern plateau populations rapidly showed admixture associated with millet farmers by 4700 B.P. in the Gonghe Basin. High genetic similarity on the southern and southwestern plateau showed population expansion along the Yarlung Tsangpo River since 3400 years ago. Central and southeastern plateau populations revealed extensive genetic admixture within the plateau historically, with substantial ancestry related to that found in southern and southwestern plateau populations. Over the past ~700 years, substantial gene flow from lowland East Asia further shaped the genetic landscape of present-day plateau populations. The high-altitude adaptive EPAS1 allele was found in plateau populations as early as in a 5100-year-old individual and showed a sharp increase over the past 2800 years.

Archaeological evidence for initial migration of Neolithic Proto Sino-Tibetan speakers from Yellow River valley to Tibetan Plateau

Sino-Tibetan is the second largest language family in the world. Recent linguistic and genetic studies have traced its origin to Neolithic millet farmers in the Yellow River region of China around 8,000 y ago and also suggested that initial divergence among branches of Sino-Tibetan coincided with expansion of the Neolithic Yangshao culture to the west and southwest during the sixth millennium BP. However, archaeological investigations to date have been insufficient to understand the lifeways of these migrant Proto Sino-Tibetan speakers. Here, we present the results of the interdisciplinary research on the material culture and ritual activities related to the initial southwestward migration of Yangshao populations, based on evidence from microfossil remains on ceramics at three sites in Gansu and Sichuan, regional archaeological contexts, and ethnographic accounts of modern Gyalrong Tibetans. The first Yangshao migrants may have integrated with indigenous hunter-gatherers in the NW Sichuan highlands, and adopted broad-spectrum subsistence strategies, consisting of both millet farming and foraging for local wild resources. Meanwhile, the migrants appear to have retained important ritual traditions previously established in their Yellow River homelands. They prepared qu starter with Monascus mold and rice for brewing alcoholic beverages, which may have been consumed in communal drinking festivals associated with the performance of ritual dancing. Such ritual activities, which to some extent have survived in the skorbro-zajiu ceremonies in SW China, may have then played a central role in maintaining and reinforcing cultural identities, social values, and connections with the homelands of the Proto Sino-Tibetan migrants.

Cultural and demic co-diffusion of Tubo Empire on Tibetan Plateau

A high point of Tibetan Plateau (TP) civilization, the expansive Tubo Empire (618-842 AD) wielded great influence across ancient western China. However, whether the Tubo expansion was cultural or demic remains unclear due to sparse ancient DNA sampling. Here, we reported ten ancient genomes at 0.017- to 0.867-fold coverages from the Dulan site with typical Tubo archaeological culture dating to 1308-1130 BP. Nine individuals from three different grave types have close relationship with previously reported ancient highlanders from the southwestern Himalayas and modern core-Tibetan populations. A Dulan-related Tubo ancestry contributed overwhelmingly (95%-100%) to the formation of modern Tibetans. A genetic outlier with dominant Eurasian steppe-related ancestry suggesting a potential population movement into the Tubo-controlled regions from Central Asia. Together with archeological evidence from burial styles and customs, our study suggested the impact of the Tubo empire on the northeast edge of the TP involved both cultural and demic diffusion.

Genetic admixture history and forensic characteristics of Tibeto-Burman-speaking Qiang people explored via the newly developed Y-STR panel and genome-wide SNP data

Fine-scale patterns of population genetic structure and diversity of ethnolinguistically diverse populations are important for biogeographical ancestry inference, kinship testing, and development and validation of new kits focused on forensic personal identification. Analyses focused on forensic markers and genome-wide single nucleotide polymorphism (SNP) data can provide new insights into the origin, admixture processes, and forensic characteristics of targeted populations. Qiang people had a large sample size among Tibeto-Burmanspeaking populations, which widely resided in the middle latitude of the Tibetan Plateau. However, their genetic structure and forensic features have remained uncharacterized because of the paucity of comprehensive genetic analyses. Here, we first developed and validated the forensic performance of the AGCU-Y30 Y-short tandem repeats (STR) panel, which contains slowly and moderately mutating Y-STRs, and then we conducted comprehensive population genetic analyses based on Y-STRs and genome-wide SNPs to explore the admixture history of Qiang people and their neighbors. The validated results of this panel showed that the new Y-STR kit was sensitive and robust enough for forensic applications. Haplotype diversity (HD) ranging from 0.9932 to 0.9996 and allelic frequencies ranging from 0.001946 to 0.8326 in 514 Qiang people demonstrated that all included markers were highly polymorphic in Tibeto-Burman people. Population genetic analyses based on Y-STRs [RST, FST, multidimensional scaling (MDS) analysis, neighboring-joining (NJ) tree, principal component analysis (PCA), and median-joining network (MJN)] revealed that the Qiang people harbored a paternally close relationship with lowland Tibetan-Yi corridor populations. Furthermore, we conducted a comprehensive population admixture analysis among modern and ancient Eurasian populations based on genome-wide shared SNPs. We found that the Qiang people were a genetically admixed population and showed closest relationship with Tibetan and Neolithic Yellow River farmers. Admixture modeling showed that Qiang people shared the primary ancestry related to Tibetan, supporting the hypothesis of common origin between Tibetan and Qiang people from North China.

Ancient DNA from Tubo Kingdom-related tombs in northeastern Tibetan Plateau revealed their genetic affinity to both Tibeto-Burman and Altaic populations

The rise of the Tubo Kingdom is considered as the key period for the formation of modern groups on the Tibetan Plateau. The ethnic origin of the residents of the Tubo Kingdom is quite complex, and their genetic structure remains unclear. The tombs of the Tubo Kingdom period in Dulan County, Qinghai Province, dating back to the seventh century, are considered to be the remains left by Tubo conquerors or the Tuyuhun people dominated by the Tubo Kingdom. The human remains of these tombs are ideal materials for studying the population dynamics in the Tubo Kingdom. In this paper, we analyzed the genome-wide data of eight remains from these tombs by shotgun sequencing and multiplex PCR panels and compared the results with data of available ancient and modern populations across East Asia. Genetic continuity between ancient Dulan people with ancient Xianbei tribes in Northeast Asia, ancient settlers on the Tibetan Plateau, and modern Tibeto-Burman populations was found. Surprisingly, one out of eight individuals showed typical genetic features of populations from Central Asia. In summary, the genetic diversity of ancient Dulan people and their affiliations with other populations provide an example of the complex origin of the residents in the Tubo Kingdom and their long-distance connection with populations in a vast geographic region across ancient Asia.

Genomic insight into the population history and biological adaptations of high-altitude Tibetan highlanders in Nagqu

Tibetan, one of the largest indigenous populations living in the high-altitude region of the Tibetan Plateau (TP), has developed a suite of physiological adaptation strategies to cope with the extreme highland environment in TP. Here, we reported genome-wide SNP data from 48 Kham-speaking Nagqu Tibetans and analyzed it with published data from 1,067 individuals in 167 modern and ancient populations to characterize the detailed Tibetan subgroup history and population substructure. Overall, the patterns of allele sharing and haplotype sharing suggested (1) the relatively genetic homogeny between the studied Nagqu Tibetans and ancient Nepalese as well as present-day core Tibetans from Lhasa, Nagqu, and Shigatse; and (2) the close relationship between our studied Kham-speaking Nagqu Tibetans and Kham-speaking Chamdo Tibetans. The fitted qpAdm models showed that the studied Nagqu Tibetans could be fitted as having the main ancestry from late Neolithic upper Yellow River millet farmers and deeply diverged lineages from Southern East Asians (represented by Upper Paleolithic Guangxi_Longlin and Laos_Hoabinhian), and a non-neglectable western Steppe herder-related ancestry (∼3%). We further scanned the candidate genomic regions of natural selection for our newly generated Nagqu Tibetans and the published core Tibetans via FST, iHS, and XP-EHH tests. The genes overlapping with these regions were associated with essential human biological functions such as immune response, enzyme activity, signal transduction, skin development, and energy metabolism. Together, our results shed light on the admixture and evolutionary history of Nagqu Tibetan populations.

Genetic Admixture History and Forensic Characteristics of Guizhou Sui People Inferred From Autosomal Insertion/Deletion and Genome-Wide Single-Nucleotide Polymorphisms

Insertion-deletion (Indel) serves as one of the important markers in forensic personal identification and parentage testing, especially for cases with degraded samples. However, the genetic diversity and forensic features in ethnolinguistically diverse southwestern Chinese populations remain to be explored. Sui, one Tai-Kadai-speaking population residing in Guizhou, has a complex genetic history based on linguistic, historic, and anthropological evidence. In this study, we genotyped 30 Indels from 511 Guizhou Sui individuals and obtained approximately 700,000 genome-wide single-nucleotide polymorphisms (SNPs) in 15 representative Sui individuals to comprehensively characterize the genetic diversity, forensic characteristics, and genomic landscape of Guizhou Sui people. The estimated forensic statistically allele frequency spectrum and parameters demonstrated that this Indels panel was polymorphic and informative in Tai-Kadai populations in southern China. Results of principal component analysis (PCA), STRUCTURE, and phylogenetic trees showed that Guizhou Sui had a close genetic relationship with geographically close Tai-Kadai and Hmong-Mien people. Furthermore, genomic analysis based on the Fst and f4-statistics further suggested the genetic affinity within southern Chinese Tai-Kadai-speaking populations and a close relationship with geographically adjoining Guizhou populations. Admixture models based on the ADMIXTURE, f4, three-way qpAdm, and ALDER results demonstrated the interaction between the common ancestor for Tai-Kadai/Austronesian, Hmong-Mien, and Austroasiatic speaking populations played a significant role in the formation of modern Tai-Kadai people. We observed a sex-biased influence in Sui people by finding that the dominant Y chromosomal type was a Hmong-Mien specific lineage O2a2a1a2a1a2-N5 but the mtDNA lineages were commonly found in Tai-Kadai populations. The additional southward expansion of millet farmers in the Yellow River Basin has impacted the gene pool of southern populations including Tai-Kadai. The whole-genome sequencing in the future will shed more light on the finer genetic profile of Guizhou populations.

Fine-Scale Population Admixture Landscape of Tai–Kadai-Speaking Maonan in Southwest China Inferred From Genome-Wide SNP Data

Guizhou Province harbors extensive ethnolinguistic and cultural diversity with Sino-Tibetan-, Hmong–Mien-, and Tai–Kadai-speaking populations. However, previous genetic analyses mainly focused on the genetic admixture history of the former two linguistic groups. The admixture history of Tai–Kadai-speaking populations in Guizhou needed to be characterized further. Thus, we genotyped genome-wide SNP data from 41 Tai–Kadai-speaking Maonan people and made a comprehensive population genetic analysis to explore their genetic origin and admixture history based on the pattern of the sharing alleles and haplotypes. We found a genetic affinity among geographically different Tai–Kadai-speaking populations, especially for Guizhou Maonan people and reference Maonan from Guangxi. Furthermore, formal tests based on the f₃/f₄-statistics further identified an adjacent connection between Maonan and geographically adjacent Hmong–Mien and Sino-Tibetan people, which was consistent with their historically documented shared material culture (Zhang et al., iScience, 2020, 23, 101032). Fitted qpAdm-based two-way admixture models with ancestral sources from northern and southern East Asians demonstrated that Maonan people were an admixed population with primary ancestry related to Guangxi historical people and a minor proportion of ancestry from Northeast Asians, consistent with their linguistically supported southern China origin. Here, we presented the landscape of genetic structure and diversity of Maonan people and a simple demographic model for their evolutionary process. Further whole-genome-sequence–based projects can be presented with more detailed information about the population history and adaptative history of the Guizhou Maonan people.

The genomic history of southwestern Chinese populations demonstrated massive population migration and admixture among proto-Hmong-Mien speakers and incoming migrants

Southwest China was the crossroad for the initial settler people of East Asia, which shows the highest diversity in languages and genetics. This region played a significant role in the formation of the genetic makeup of the proto-Hmong-Mien-speaking people and in the north-to-south human expansion during the Neolithic-to-historic transformation. Their genetic history covering migration events and the admixture processes still needs to be further explored. Therefore, in the current study, we have generated genome-wide data from three genomic aspects covering autosomal, mitochondrial and Y-chromosomal regions in 260 Hmong-Mien, Tibeto-Burman, and Sinitic people from 29 different southwestern Chinese groups, and further analyzed them with 2676 published modern and ancient Eurasian genomes. Here, we have noticed a new southwestern East Asian genetic cline composed of the Hmong-Mien-specific ancestry enriched in modern Hmong and Pathen. This newly identified southern inland East Asian lineage contributed to a great extent of the gene pool in the modern southern East Asians. We also have observed genetic substructure among Hmong-Mien-speaking populations. The southern Hmong-Mien-speaking people showed more genetic affinity with modern Tai-Kadai/Austroasiatic people, while the northern Hmong-Mien speakers expressed a closer genetic connection with the Neolithic-to-modern northern East Asians. Moreover, southwestern Sinitic populations had a strong genomic affinity with the adjacent Hmong-Mien-speaking populations and the lowlander Tibeto-Burman-speaking populations, which suggested the large-scale genetic admixture occurred between them. Allele-sharing-based qpAdm/qpGraph results further confirmed that all included southwestern Chinese populations could be modeled as a mixed result of the major ancestry component from the northern millet farmers in the Yellow River basin and the minor ancestry component from the southern rice farmers in the Yangtze River basin. Usually, this newly identified Hmong-Mien-associated southern East Asian ancestry could improve our understanding of the full-scale genetic landscape of the evolutionary and admixture history of southwestern East Asians. Further ancient genomic studies from southeastern China are required to shed deeper light on our established phylogeny context.

Genomic Insight Into the Population Admixture History of Tungusic-Speaking Manchu People in Northeast China

Manchu is the third-largest ethnic minority in China and has the largest population size among the Tungusic-speaking groups. However, the genetic origin and admixture history of the Manchu people are far from clear due to the sparse sampling and a limited number of markers genotyped. Here, we provided the first batch of genome-wide data of genotyping approximate 700,000 single-nucleotide polymorphisms (SNPs) in 93 Manchu individuals collected from northeast China. We merged the newly generated data with data of publicly available modern and ancient East Asians to comprehensively characterize the genetic diversity and fine-scale population structure, as well as explore the genetic origin and admixture history of northern Chinese Manchus. We applied both descriptive methods of ADMIXTURE, fineSTRUCTURE, F ST , TreeMix, identity by decedent (IBD), principal component analysis (PCA), and qualitative f-statistics (f 3, f 4, qpAdm, and qpWave). We found that Liaoning Manchus have a close genetic relationship and significant admixture signal with northern Han Chinese, which is in line with the cluster patterns in the haplotype-based results. Additionally, the qpAdm-based admixture models showed that modern Manchu people were formed as major ancestry related to Yellow River farmers and minor ancestry linked to ancient populations from Amur River Bain, or others. In summary, the northeastern Chinese Manchu people in Liaoning were an exception to the coherent genetic structure of Tungusic-speaking populations, probably due to the large-scale population migrations and genetic admixtures in the past few hundred years.