title: Genetic structure of Tibeto-Burman populations of Bangladesh: evaluating the gene flow along the sides of Bay-of-Bengal.
abstract: 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.
authors.affiliation: Center for Advanced Research in Physical, Chemical, Biological and Pharmaceutical Sciences, University of Dhaka, Dhaka, Bangladesh.
authors.forename: Nurun Nahar
authors.initials: NN
authors.lastname: Gazi
authors.forename: Rakesh
authors.initials: R
authors.lastname: Tamang
authors.forename: Vipin Kumar
authors.initials: VK
authors.lastname: Singh
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ferdous
authors.forename: Ajai Kumar
authors.initials: AK
authors.lastname: Pathak
authors.forename: Mugdha
authors.initials: M
authors.lastname: Singh
authors.forename: Sharath
authors.initials: S
authors.lastname: Anugula
authors.forename: Pandichelvam
authors.initials: P
authors.lastname: Veeraiah
authors.forename: Subburaj
authors.initials: S
authors.lastname: Kadarkaraisamy
authors.forename: Brijesh Kumar
authors.initials: BK
authors.lastname: Yadav
authors.forename: Alla G
authors.initials: AG
authors.lastname: Reddy
authors.forename: Deepa Selvi
authors.initials: DS
authors.lastname: Rani
authors.forename: Syed Saleheen
authors.initials: SS
authors.lastname: Qadri
authors.forename: Lalji
authors.initials: L
authors.lastname: Singh
authors.forename: Gyaneshwer
authors.initials: G
authors.lastname: Chaubey
authors.forename: Kumarasamy
authors.initials: K
authors.lastname: Thangaraj
mesh_terms: D001459:Bangladesh; D004272:DNA, Mitochondrial / Q000235:genetics; D051456:Gene Flow / Q000235:genetics; D005828:Genetics, Population / Q000379:methods*; D005843:Geography; D006239:Haplotypes / Q000235:genetics; D006801:Humans
chemical_list: D004272:DNA, Mitochondrial