Tibeto-Burman Speakers Research Articles

The maternal genetic origin and diversity of the extant populations of the Ladakh region in India

Ladakh lies at a strategic location between the Indus River valley and the Hindu Khush Mountains, which makes the “Land of high passes” one of the major routes of movement. Through the years the region has faced multi-layered cultural movements, genetic assimilation and demographic changes. The initial settlement in the years goes back to the early Neolithic age and still continues despite its harsh, unhospitable and cold climate. Previous studies mostly covered the patrilineal markers of the region and an in-depth study lacked to represent the matrilineal ancestry and possible genetic inflow in the region. Hence, our current study first time generated complete mitogenomes of 108 unrelated individuals from Ladakh belonging to three population groups namely, Changpa (n = 38), Brokpa (n = 32) and Monpa (n = 38). In the in-depth analysis, we found that the mitogenome of the three Ladakhi groups are highly diverse in terms of maternal haplogroup distribution carrying lineages specific to East Asia (M9a), Tibbet (A21) and South Asia (M3, M30, U2). In our analysis we found that Changpa and Monpa probably have shared maternal ancestry compared to Brokpa, which is very distinct and also later suffered possible historical Bottleneck. Bayesian evolutionary and Network analysis indicates more ancient maternal lineage of Changpa and Monpa in terms of M9a haplotypes, but they also share some genetic history with Tibeto-Burman speakers in past. These findings conclusively indicate possible matrilineal genetic inflow in Ladakh from three directions, primarily from East Asia or South East Asia during post-glacial, West Eurasia and also from South Asia.

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.

Genomic formation of Tibeto-Burman speaking populations in Guizhou, Southwest China

Sino-Tibetan is the most prominent language family in East Asia. Previous genetic studies mainly focused on the Tibetan and Han Chinese populations. However, due to the sparse sampling, the genetic structure and admixture history of Tibeto-Burman-speaking populations in the low-altitude region of Southwest China still need to be clarified. We collected DNA from 157 individuals from four Tibeto-Burman-speaking groups from the Guizhou province in Southwest China. We genotyped the samples at about 700,000 genome-wide single nucleotide polymorphisms. Our results indicate that the genetic variation of the four Tibeto-Burman-speaking groups in Guizhou is at the intermediate position in the modern Tibetan-Tai-Kadai/Austronesian genetic cline. This suggests that the formation of Tibetan-Burman groups involved a large-scale gene flow from lowland southern Chinese. The southern ancestry could be further modelled as deriving from Vietnam’s Late Neolithic-related inland Southeast Asia agricultural populations and Taiwan’s Iron Age-related coastal rice-farming populations. Compared to the Tibeto-Burman speakers in the Tibetan-Yi Corridor reported previously, the Tibeto-Burman groups in the Guizhou region received additional gene flow from the southeast coastal area of China. We show a difference between the genetic profiles of the Tibeto-Burman speakers of the Tibetan-Yi Corridor and the Guizhou province. Vast mountain ranges and rivers in Southwest China may have decelerated the westward expansion of the southeast coastal East Asians. Our results demonstrate the complex genetic profile in the Guizhou region in Southwest China and support the multiple waves of human migration in the southern area of East Asia.

Risk Assessment of Esophageal Cancer Prevalence in North East India

Background: The North East (NE) India region has a quite distinct gene pool with over 160 scheduled tribes and 400 other sub-tribal populations. This region is the fourth contributor to the gene pool of the Indian sub-continent, which has associations with Tibeto-Burman speakers and Austro-Asiatic speakers settled in East and NE-India with Asian ties. Methods: Literature search and studies have shown that in India, notwithstanding the lack of data on population coverage, there exists no such evidence for a decline in age-standardized mortality rates in cancer and the number of deaths mostly in individuals less than 70 years. Results: Analytical epidemiological studies using molecular markers are currently the need of NEIndia for prognostication of cancers in this region, which are quite different from the rest of India, such as esophageal cancer, lung cancer in females, stomach cancer, and nasopharyngeal cancers. In addition, there is a dire need for translational research in NE-India, as for cancer survival, it is not always feasible to generalize the current international guidelines for cancer to the population of NEIndia so that high survival rates are achieved just like the rest of India and high-income rich countries. Factors, such as difference in incidence rate, socioeconomic factors, tumor biology and availability of resource in this region, determine the survival rates. Conclusion: In this review, various factors involved in the high cancer burden in this region are discussed, particularly focusing on the genetic basis.

Elevation and fog-cloud similarity in Tibeto-Burman languages

Lexically, 52.99% of the Tibeto-Burman languages, the non-Sinitic branches of the Sino-Tibetan language family, treat fog as something identical or similar to cloud, based on our database of 234 Tibeto-Burman varieties; there are three lexical relations of such fog-cloud similarity in Tibeto-Burman languages, namely cloud colexified with fog, cloud as a hypernym of fog, and cloud as a formative of fog. The rest of the Tibeto-Burman languages use semantically disconnected words to describe fog and cloud. The high proportion of fog-cloud similarity in Tibeto-Burman languages, compared with that of the non-Tibeto-Burman languages spoken alongside the Trans-Himalayan region (i.e., 10.80%, a result based on our database of 213 non-Tibeto-Burman varieties), has its historical reason, namely the relics of Proto-Tibeto-Burman. However, other than the phylogenetic factors, an underlying reason can be attributed to the environmental influence. The present findings indicate that fog-cloud similarity is more likely to happen at higher elevations, particularly between the range of 1000 m to 3000 m above sea level. After reviewing the meteorological features, it is found that the Tibeto-Burman region has ideal conditions for the formation of low cloud, namely with high humidity and through orographic uplift due to the mountainous environment. Since Tibeto-Burman speakers live in high elevations, low cloud, the dominant cloud of the region, may surround them or beneath their view. Therefore, they may find it difficult or not necessary to distinguish fog from low cloud. Our conclusion is also supported by the languages of other families and regions, such as the Daghestanian languages of the Caucasus region and the languages of the Central Andes. Moreover, the present findings agree with the theory of efficient communication. That is, languages displaying fog-cloud similarity are adaptive to higher elevations with less communicative need to distinguish between the two concepts by using completely different and unrelated linguistic forms; on the contrary, languages displaying fog-cloud divergence have stronger need to do so, resulting as well from their adaptation to the extra-linguistic environment. Finally, tropical climates, another possible predictor for fog-cloud similarity, are identified as a future research direction.

The southern genetic influence on Tibeto-Burman speaking populations in southwest China inferred from genome-wide array genotyping

The southern genetic influence on Tibeto-Burman speaking populations in southwest China inferred from genome-wide array genotyping

Multiple migrations from East Asia led to linguistic transformation in NorthEast India and mainland Southeast Asia.

NorthEast India, with its unique geographic location in the midst of the Himalayas and Bay of Bengal, has served as a passage for the movement of modern humans across the Indian subcontinent and East/Southeast Asia. In this study we look into the population genetics of a unique population called the Khasi, speaking a language (also known as the Khasi language) belonging to the Austroasiatic language family and residing amidst the Tibeto-Burman speakers as an isolated population. The Khasi language belongs to one of the three major broad classifications or phyla of the Austroasiatic language and the speakers of the three sub-groups are separated from each other by large geographical distances. The Khasi speakers are separated from their nearest Austroasiatic language-speaking sub-groups: the “Mundari” sub-family from East and peninsular India and the “Mon-Khmers” in Mainland Southeast Asia. We found the Khasi population to be genetically distinct from other Austroasiatic speakers, i.e. Mundaris and Mon-Khmers, but relatively similar to the geographically proximal Tibeto Burmans. The possible reasons for this genetic-linguistic discordance lie in the admixture history of different migration events that originated from East Asia and proceeded possibly towards Southeast Asia. We found at least two distinct migration events from East Asia. While the ancestors of today’s Tibeto-Burman speakers were affected by both, the ancestors of Khasis were insulated from the second migration event. Correlating the linguistic similarity of Tibeto-Burman and Sino-Tibetan languages of today’s East Asians, we infer that the second wave of migration resulted in a linguistic transition while the Khasis could preserve their linguistic identity.

Ancient genomes from the Himalayas illuminate the genetic history of Tibetans and their Tibeto-Burman speaking neighbors

Present-day Tibetans have adapted both genetically and culturally to the high altitude environment of the Tibetan Plateau, but fundamental questions about their origins remain unanswered. Recent archaeological and genetic research suggests the presence of an early population on the Plateau within the past 40 thousand years, followed by the arrival of subsequent groups within the past 10 thousand years. Here, we obtain new genome-wide data for 33 ancient individuals from high elevation sites on the southern fringe of the Tibetan Plateau in Nepal, who we show are most closely related to present-day Tibetans. They derive most of their ancestry from groups related to Late Neolithic populations at the northeastern edge of the Tibetan Plateau but also harbor a minor genetic component from a distinct and deep Paleolithic Eurasian ancestry. In contrast to their Tibetan neighbors, present-day non-Tibetan Tibeto-Burman speakers living at mid-elevations along the southern and eastern margins of the Plateau form a genetic cline that reflects a distinct genetic history. Finally, a comparison between ancient and present-day highlanders confirms ongoing positive selection of high altitude adaptive alleles.

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

Archeologically attested human occupation on the Tibetan Plateau (TP) can be traced back to 160 thousand years ago (kya) via the archaic Xiahe people and 30∼40 kya via the Nwya Devu anatomically modern human. However, the history of the Tibetan populations and their migration inferred from the ancient and modern DNA remains unclear. Here, we performed the first ancient and modern genomic meta-analysis among 3,017 Paleolithic to present-day Eastern Eurasian genomes (2,444 modern individuals from 183 populations and 573 ancient individuals). We identified a close genetic connection between the ancient-modern highland Tibetans and lowland island/coastal Neolithic Northern East Asians (NEA). This observed genetic affinity reflected the primary ancestry of high-altitude Tibeto-Burman speakers originated from the Neolithic farming populations in the Yellow River Basin. The identified pattern was consistent with the proposed common north-China origin hypothesis of the Sino-Tibetan languages and dispersal patterns of the northern millet farmers. We also observed the genetic differentiation between the highlanders and lowland NEAs. The former harbored more deeply diverged Hoabinhian/Onge-related ancestry and the latter possessed more Neolithic southern East Asian (SEA) or Siberian-related ancestry. Our reconstructed qpAdm and qpGraph models suggested the co-existence of Paleolithic and Neolithic ancestries in the Neolithic to modern East Asian highlanders. Additionally, we found that Tibetans from Ü-Tsang/Ando/Kham regions showed a strong population stratification consistent with their cultural background and geographic terrain. Ü-Tsang Tibetans possessed a stronger Chokhopani-affinity, Ando Tibetans had more Western Eurasian related ancestry and Kham Tibetans harbored greater Neolithic southern EA ancestry. Generally, ancient and modern genomes documented multiple waves of human migrations in the TP’s past. The first layer of local hunter-gatherers mixed with incoming millet farmers and arose the Chokhopani-associated Proto-Tibetan-Burman highlanders, which further respectively mixed with additional genetic contributors from the western Eurasian Steppe, Yellow River and Yangtze River and finally gave rise to the modern Ando, Ü-Tsang and Kham Tibetans.

Combined Low-/High-Density Modern and Ancient Genome-Wide Data Document Genomic Admixture History of High-Altitude East Asians.

The Tibetan Plateau (TP) is considered to be one of the last terrestrial environments conquered by the anatomically modern human. Understanding of the genetic background of highland Tibetans plays a pivotal role in archeology, anthropology, genetics, and forensic investigations. Here, we genotyped 22 forensic genetic markers in 1,089 Tibetans residing in Nagqu Prefecture and collected 1,233,013 single nucleotide polymorphisms (SNPs) in the highland East Asians (Sherpa and Tibetan) from the Simons Genome Diversity Project and ancient Tibetans from Nepal and Neolithic farmers from northeastern Qinghai-Tibetan Plateau from public databases. We subsequently merged our two datasets with other worldwide reference populations or eastern ancient Eurasians to gain new insights into the genetic diversity, population movements, and admixtures of high-altitude East Asians via comprehensive population genetic statistical tools [principal component analysis (PCA), multidimensional scaling plot (MDS), STRUCTURE/ADMIXTURE, f3, f4, qpWave/qpAdm, and qpGraph]. Besides, we also explored their forensic characteristics and extended the Chinese National Database based on STR data. We identified 231 alleles with the corresponding allele frequencies spanning from 0.0005 to 0.5624 in the forensic low-density dataset, in which the combined powers of discrimination and the probability of exclusion were 1–1.22E-24 and 0.999999998, respectively. Additionally, comprehensive population comparisons in our low-density data among 57 worldwide populations via the Nei’s genetic distance, PCA, MDS, NJ tree, and STRUCTURE analysis indicated that the highland Tibeto-Burman speakers kept the close genetic relationship with ethnically close populations. Findings from the 1240K high-density dataset not only confirmed the close genetic connection between modern Highlanders, Nepal ancients (Samdzong, Mebrak, and Chokhopani), and the upper Yellow River Qijia people, suggesting the northeastern edge of the TP served as a geographical corridor for ancient population migrations and interactions between highland and lowland regions, but also evidenced that late Neolithic farmers permanently colonized into the TP by adopting cold-tolerant barley agriculture that was mediated via the acculturation of idea via the millet farmer and not via the movement of barley agriculturalist as no obvious western Eurasian admixture signals were identified in our analyzed modern and ancient populations. Besides, results from the qpAdm-based admixture proportion estimation and qpGraph-based phylogenetic relationship reconstruction consistently demonstrated that all ancient and modern highland East Asians harbored and shared the deeply diverged Onge/Hoabinhian-related eastern Eurasian lineage, suggesting a common Paleolithic genetic legacy existed in high-altitude East Asians as the first layer of their gene pool.

Linguistic evidence supports a long antiquity of cultivation of barley and buckwheat over that of millet and rice in Eastern Bhutan

Little is known about the prehistoric domestication and cultivation of crops in the Eastern Himalayas (eastern Nepal, Bhutan, Sikkim, Arunachal Pradesh), due to a lack of archaeological and archaeobotanical research in the area. This paper reconstructs the lexical terminology for grains in the East Bodish language sub-family in Eastern Bhutan. Historical linguistic methods suggest that the immediate ancestors of the modern East Bodish speakers cultivated buckwheat (Fagopyrum) and barley (Hordeum) but not millets or rice. Buckwheat was traditionally thought to have been domesticated in Southwest China; however, this research reveals that cultivation (and potentially subsequent domestication) may have taken place among East Bodish language speakers or their ancestors. These findings also pose a challenge for studies which seek to reconstruct millets to ancestral Tibeto-Burman speaking populations.

Dissecting the paternal founders of Mundari (Austroasiatic) speakers associated with the language dispersal in South Asia.

The phylogenetic analysis of Y chromosomal haplogroup O2a-M95 was crucial to determine the nested structure of SouthAsian branches within the larger tree, predominantly present in East and Southeast Asia. However, it had previously been unclear that how many founders brought the haplogroup O2a-M95 to South Asia. On the basis of the updated Y chromosomal tree for haplogroup O2a-M95, we analysed 1437 male samples from South Asia for various novel downstream markers, carefully selected from the extant phylogenetic tree. With this increased resolutionof genetic markers, we were able to identify at least three founders downstream to haplogroup O2a-M95, who are likely to have been associated with the dispersal of Austroasiatic languages to South Asia. The fourth founder was exclusively present amongst Tibeto-Burman speakers of Manipur and Bangladesh. In sum, our new results suggest the arrival of Austroasiatic languages in South Asia during last 5000 years.

Genome-wide analysis of unrecognised ethnic group Chuanqing people revealing a close affinity with Southern Han Chinese

Background Chuanqing is an unrecognised ethnic group in Guizhou, southwest China. The genetic history of the Chuanqing people is hotly debated due to a lack of available genetic data. Aim To infer the genetic structure and population history of the Chuanqing people and genetic relationships of the Chuanqing with other East Asians. Subjects and methods We collected samples from 14 Chuanqing individuals from Guizhou and genotyped about 690,000 genome-wide single nucleotide polymorphisms (SNPs). We used Principal Component Analysis (PCA), ADMIXTURE analysis, and f statistics to infer the population genetic structure and admixture. Results Chuanqing people show a distinct genetic profile from indigenous Tai-Kadai and Tibeto-Burman speaking populations in southwest China, but they are genetically similar to southern Han Chinese, Miao, She and Tujia populations. The Han Chinese characteristic Y chromosomal lineages reach high frequencies in the Chuanqing. Conclusions The genetic formation of the Chuanqing people has been greatly influenced by Han Chinese related populations.

Tai-Kadai-speaking Gelao population: Forensic features, genetic diversity and population structure

Genetic analyses of geographically and ethno-linguistically different populations are essential for understanding population stratification and genomic structure in medical Genome-Wide Association Studies (GWAS) and genetic variation and diversity related to forensic and population genetics studies. Here, we genotyped 30 autosomal insertion/deletion (Indel) markers from 502 Tai-Kadai-speaking Gelao individuals residing in the rugged topographical area in Southeastern China. In addition, two comprehensive population genetic comparisons of 15,327 individuals from 95 worldwide populations and of 6122 individuals from Asia and adjoining populations were conducted based on allele frequency data and raw genotype data, respectively. All studied markers were found to be in Hardy-Weinberg equilibrium. The combined power of discrimination in the Gelao minority group was 0.999999999975, and the combined probability of exclusion was 0.9879. Our results from the forensic statistical parameters indicated that this Indel panel can be independently used as a powerful tool in forensic individual identification but can only be used as a complementary tool in paternity cases involving East Asians. We also found significant allele frequency differences between the Gelao and other continental populations with respect to the markers grouped in clusters ∼Ⅳ, suggesting that these can be used as forensic ancestry informative Indel markers to distinguish the Gelao from other continental populations. Genetic ancestry analyses demonstrated that Tai-Kadai-speaking Gelao share a dominant ancestry component with Hmong-Mien-speaking Miao. Our population genetic results from multidimensional scaling plots, principal component analysis, neighboring-joining tree construction and hierarchical clustering also suggested that the Zunyi Gelao are genetically closer to their linguistically or geographically close populations, such as the Han Chinese, Guizhou Bouyei and the Hubei Tujia, than to Turkic and Tibeto-Burman speakers.

Alu insertion-deletion polymorphisms in the Tibeto-Burman speaking tribal groups of Manipur, North-East India

IntroductionZeme, Liangmai, Rongmei, Inpui and Kuki tribes are the hill inhabitants of Manipur who belong to Tibeto Burman speaking groups. AimThe present study attempt to assess the nature and extent of gene diversity and genetic affinities among the five tribal groups of Manipur. MethodsFive alu indel markers were screened for 460 individuals of five tribal groups of Manipur. Results and conclusionAll the five loci are found to be polymorphic. Genotype frequencies for all the loci are in reasonable agreement with their respective Hardy-Weinberg proportions except in PV92 among the Kuki tribe. Average heterozygosity levels are high and degree of differentiation is low (Gst-1.86%), revealing that genetic drift is unlikely to play a significant role in the process of genetic differentiation. The genetic structure by and large revealed that the population groups of Manipur are neither overtly admixed nor isolated. Furthermore, dendrogram showing close affinities between Zeme, Liangmai, Rongmei, and Inpui is in accordance with the common origin theory given by AZSU (2009).

Massively parallel sequencing of 165 ancestry informative SNPs in two Chinese Tibetan-Burmese minority ethnicities

The Tibeto-Burman language, one subfamily of the Sino-Tibetan languages, is spoken by over 60 million people all over East Asia. Yet the ethnic origin and genetic architecture of Tibeto-Burman speaking populations remain largely unexplored. In the present study, 169 Chinese individuals from Tibeto-Burman speaking populations (two ethnic groups: Tibetan and Yi) in four different geographic regions in western China were analyzed using the Precision ID Ancestry Panel (165 AISNPs) and the Ion PGM System. The performance and corresponding forensic statistical parameters of this AISNPs panel were investigated. Comprehensive population genetic comparisons (143 populations based on Kidd’ SNPs, 92 populations on the basis of Seldin’ SNPs and 31 populations based on the Precision ID Ancestry Panel) and ancestry inference were further performed. Sequencing performance demonstrated that the Precision ID Ancestry Panel is effective and robust. Forensic characteristics suggested that this panel not only can be used for ancestry estimation of Tibeto-Burman populations but also for individual identification. Tibetan and Yi shared a common genetic ancestry origin but experienced the complex history of gene flow, local adaptation, and isolation, and constructed the specific genetic landscape of human genetic diversity of Highlander and Lowlander populations. Tibetan-Burman populations and other East Asian populations showed sufficient genetic difference and could be distinguished into three distinct groups. Furthermore, analysis of population structure revealed that significant genetic difference was existed inter-continent populations and strong genetic affinity was observed within-continent populations. Additional population-specific AISNPs and a relatively more comprehensive database with sufficient reference population data remain necessary to get better-scale resolution within a geographically proximate populations in East Asia.

Insurgency in the State of North-East

The North East is one of the most ethnically and linguistically diverse regions in India. The numerous fairs and festivals celebrated by these communities and their friendly nature are irresistible attractions for the visitors. However, the maximum concentration of the Tibeto-Burman speakers is found in the North East: in comparison to any part of the Country. The problem of insurgency in the Northeast has reached all-time high. Almost all Northeast is under Armed forces under special powers Act. Their presence is due to unrest or ethnic uprising, which is due to unemployment, intolerance, frustration and alienation among the people in general, and youths in particular. There are many reasons behind the problem of insurgency/ terrorism. Some of which is lack of political will and determination to make the people of this region to have feelings of oneness and sense of belongingness to the country. Due to not having any industrial growth, the States have lack of employment opportunity, lack of proper facilities, planning etc. The other reason is the geographical isolation/location of the states of Northeast from rest of the country. Due to this, there is lack of communication, poor transportation, no opportunity for sending agriculture and other produces outside the state etc. All these adversely affect the economic development. A number of studies showed that deprivation, unemployment, racial discrimination, ethnicity, minority status, and so on show altogether different impact on identity development. Ethnic minorities who form sub-segment in the society have low self-esteem and find themselves in a complex situation (Taifel, 1978, and Morris).

The genetic admixture in Tibetan‐Yi Corridor

The Tibetan-Yi Corridor located on the eastern edge of Tibetan Plateau is suggested to be the key region for the origin and diversification of Tibeto-Burman speaking populations and the main route of the peopling of the Plateau. However, the genetic history of the populations in the Corridor is far from clear due to limited sampling in the northern part of the Corridor. We collected blood samples from 10 Tibetan and 10 Han Chinese individuals from Gansu province and genotyped about 600,000 genome-wide single nucleotide polymorphisms (SNPs). Our data revealed that the populations in the Corridor are all admixed on a genetic cline of deriving ancestry from Tibetans on the Plateau and surrounding lowland East Asians. The Tibetan and Han Chinese groups in the north of the Plateau show significant evidence of low-level West Eurasian admixture that could be probably traced back to 600∼900 years ago. We conclude that there have been huge population migrations from surrounding lowland onto the Tibetan Plateau via the Tibetan-Yi Corridor since the initial formation of Tibetans probably in Neolithic Time, which leads to the current genetic structure of Tibeto-Burman speaking populations.

A Linguistically Informed Autosomal STR Survey of Human Populations Residing in the Greater Himalayan Region

The greater Himalayan region demarcates two of the most prominent linguistic phyla in Asia: Tibeto-Burman and Indo-European. Previous genetic surveys, mainly using Y-chromosome polymorphisms and/or mitochondrial DNA polymorphisms suggested a substantially reduced geneflow between populations belonging to these two phyla. These studies, however, have mainly focussed on populations residing far to the north and/or south of this mountain range, and have not been able to study geneflow patterns within the greater Himalayan region itself. We now report a detailed, linguistically informed, genetic survey of Tibeto-Burman and Indo-European speakers from the Himalayan countries Nepal and Bhutan based on autosomal microsatellite markers and compare these populations with surrounding regions. The genetic differentiation between populations within the Himalayas seems to be much higher than between populations in the neighbouring countries. We also observe a remarkable genetic differentiation between the Tibeto-Burman speaking populations on the one hand and Indo-European speaking populations on the other, suggesting that language and geography have played an equally large role in defining the genetic composition of present-day populations within the Himalayas.

Genetic Structure of Tibeto-Burman Populations of Bangladesh: Evaluating the Gene Flow along the Sides of Bay-of-Bengal

Human settlement and migrations along sides of Bay-of-Bengal have played a vital role in shaping the genetic landscape of Bangladesh, Eastern India and Southeast Asia. Bangladesh and Northeast India form the vital land bridge between the South and Southeast Asia. To reconstruct the population history of this region and to see whether this diverse region geographically acted as a corridor or barrier for human interaction between South Asia and Southeast Asia, we, for the first time analyzed high resolution uniparental (mtDNA and Y chromosome) and biparental autosomal genetic markers among aboriginal Bangladesh tribes currently speaking Tibeto-Burman language. All the three studied populations; Chakma, Marma and Tripura from Bangladesh showed strikingly high homogeneity among themselves and strong affinities to Northeast Indian Tibeto-Burman groups. However, they show substantially higher molecular diversity than Northeast Indian populations. Unlike Austroasiatic (Munda) speakers of India, we observed equal role of both males and females in shaping the Tibeto-Burman expansion in Southern Asia. Moreover, it is noteworthy that in admixture proportion, TB populations of Bangladesh carry substantially higher mainland Indian ancestry component than Northeast Indian Tibeto-Burmans. Largely similar expansion ages of two major paternal haplogroups (O2a and O3a3c), suggested that they arose before the differentiation of any language group and approximately at the same time. Contrary to the scenario proposed for colonization of Northeast India as male founder effect that occurred within the past 4,000 years, we suggest a significantly deep colonization of this region. Overall, our extensive analysis revealed that the population history of South Asian Tibeto-Burman speakers is more complex than it was suggested before.