Dataset Information

Population genetic structure in Indian Austroasiatic speakers: the role of landscape barriers and sex-specific admixture.

ABSTRACT: The geographic origin and time of dispersal of Austroasiatic (AA) speakers, presently settled in south and southeast Asia, remains disputed. Two rival hypotheses, both assuming a demic component to the language dispersal, have been proposed. The first of these places the origin of Austroasiatic speakers in southeast Asia with a later dispersal to south Asia during the Neolithic, whereas the second hypothesis advocates pre-Neolithic origins and dispersal of this language family from south Asia. To test the two alternative models, this study combines the analysis of uniparentally inherited markers with 610,000 common single nucleotide polymorphism loci from the nuclear genome. Indian AA speakers have high frequencies of Y chromosome haplogroup O2a; our results show that this haplogroup has significantly higher diversity and coalescent time (17-28 thousand years ago) in southeast Asia, strongly supporting the first of the two hypotheses. Nevertheless, the results of principal component and "structure-like" analyses on autosomal loci also show that the population history of AA speakers in India is more complex, being characterized by two ancestral components-one represented in the pattern of Y chromosomal and EDAR results and the other by mitochondrial DNA diversity and genomic structure. We propose that AA speakers in India today are derived from dispersal from southeast Asia, followed by extensive sex-specific admixture with local Indian populations.

SUBMITTER: Chaubey G

PROVIDER: S-EPMC3355372 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature

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Publications

Population genetic structure in Indian Austroasiatic speakers: the role of landscape barriers and sex-specific admixture.

Chaubey Gyaneshwer G Metspalu Mait M Choi Ying Y Mägi Reedik R Romero Irene Gallego IG Soares Pedro P van Oven Mannis M Behar Doron M DM Rootsi Siiri S Hudjashov Georgi G Mallick Chandana Basu CB Karmin Monika M Nelis Mari M Parik Jüri J Reddy Alla Goverdhana AG Metspalu Ene E van Driem George G Xue Yali Y Tyler-Smith Chris C Thangaraj Kumarasamy K Singh Lalji L Remm Maido M Richards Martin B MB Lahr Marta Mirazon MM Kayser Manfred M Villems Richard R Kivisild Toomas T

Molecular biology and evolution 20101026 2

The geographic origin and time of dispersal of Austroasiatic (AA) speakers, presently settled in south and southeast Asia, remains disputed. Two rival hypotheses, both assuming a demic component to the language dispersal, have been proposed. The first of these places the origin of Austroasiatic speakers in southeast Asia with a later dispersal to south Asia during the Neolithic, whereas the second hypothesis advocates pre-Neolithic origins and dispersal of this language family from south Asia. T ...[more]

PMID: 20978040

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Project description:The Caribbean is a genetically diverse region with heterogeneous admixture compositions influenced by local island ecologies, migrations, colonial conflicts, and demographic histories. The Commonwealth of Dominica is a mountainous island in the Lesser Antilles historically known to harbor communities with unique patterns of migration, mixture, and isolation. This community-based population genetic study adds biological evidence to inform post-colonial narrative histories in a Dominican horticultural village. High density single nucleotide polymorphism data paired with a previously compiled genealogy provide the first genome-wide insights on genetic ancestry and population structure in Dominica. We assessed family-based clustering, inferred global ancestry, and dated recent admixture by implementing the fastSTRUCTURE clustering algorithm, modeling graph-based migration with TreeMix, assessing patterns of linkage disequilibrium decay with ALDER, and visualizing data from Dominica with Human Genome Diversity Panel references. These analyses distinguish family-based genetic structure from variation in African, European, and indigenous Amerindian admixture proportions, and analyses of linkage disequilibrium decay estimate admixture dates 5-6 generations (~160 years) ago. African ancestry accounts for the largest mixture components, followed by European and then indigenous components; however, our global ancestry inferences are consistent with previous mitochondrial, Y chromosome, and ancestry marker data from Dominica that show uniquely higher proportions of indigenous ancestry and lower proportions of African ancestry relative to known admixture in other French- and English-speaking Caribbean islands. Our genetic results support local narratives about the community's history and founding, which indicate that newly emancipated people settled in the steep, dense vegetation along Dominica's eastern coast in the mid-19th century. Strong genetic signals of post-colonial admixture and family-based structure highlight the localized impacts of colonial forces and island ecologies in this region, and more data from other groups are needed to more broadly inform on Dominica's complex history and present diversity.

Dataset Information

Population genetic structure in Indian Austroasiatic speakers: the role of landscape barriers and sex-specific admixture.

Publications

Population genetic structure in Indian Austroasiatic speakers: the role of landscape barriers and sex-specific admixture.

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