June 18, 2009

Origin of Malagasy

Molecular Biology and Evolution doi:10.1093/molbev/msp120

On the origins and admixture of Malagasy: new evidence from high resolution analyses of paternal and maternal lineages

Sergio Tofanelli et al.


The Malagasy have been shown to be a genetically admixed population combining parental lineages with African and South East Asian ancestry. In the present paper we fit the Malagasy admixture history in a highly resolved phylogeographic framework by typing a large set of mtDNA and Y DNA markers in unrelated individuals from inland (Merina) and coastal (Antandroy, Antanosy, Antaisaka) ethnic groups. This allowed performance of a multi-level analysis in which the diversity among main ethnic divisions, lineage ancestries, and modes of inheritance could be concurrently evaluated. Admixture was confirmed to result from the encounter of African and South-East Asian people with minor recent male contributions from Europe. However, new scenarios are depicted about Malagasy admixture history. The distribution of ancestral components was ethnic- and sex-biased, with the Asian ancestry appearing more conserved in the female than in the male gene pool, and in inland than in coastal groups. A statistic based on haplotype sharing (DHS), showing low sampling error and time linearity over the last 200 generations, was here introduced for the first time and helped to integrate our results with linguistic and archeological data. The focus about the origin of Malagasy lineages was enlarged in space and pushed back in time. Homelands could not be pinpointed, but appeared to comprise two vast areas containing different populations from sub-Saharan Africa and South-East Asia. The pattern of diffusion of uni-parental lineages was compatible with at least two events: a primary admixture of proto-Malay people with Bantu-speakers bearing a western-like pool of haplotypes, followed by a secondary flow of Southeastern Bantu-speakers unpaired for gender (mainly male-driven) and geography (mainly coastal).


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