The earliest settlers antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineageReport as inadecuate




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BMC Evolutionary Biology

, 8:230

First Online: 11 August 2008Received: 06 March 2008Accepted: 11 August 2008

Abstract

BackgroundThe -out of Africa- model postulating single -southern route- dispersal posits arrival of -Anatomically Modern Human- to Indian subcontinent around 66–70 thousand years before present kyBP. However the contributions and legacy of these earliest settlers in contemporary Indian populations, owing to the complex past population dynamics and later migrations has been an issue of controversy. The high frequency of mitochondrial lineage -M2- consistent with its greater age and distribution suggests that it may represent the phylogenetic signature of earliest settlers. Accordingly, we attempted to re-evaluate the impact and contribution of earliest settlers in shaping the genetic diversity and structure of contemporary Indian populations; using our newly sequenced 72 and 4 published complete mitochondrial genomes of this lineage.

ResultsThe M2 lineage, harbouring two deep rooting subclades M2a and M2b encompasses approximately one tenth of the mtDNA pool of studied tribes. The phylogeographic spread and diversity indices of M2 and its subclades among the tribes of different geographic regions and linguistic phyla were investigated in detail. Further the reconstructed demographic history of M2 lineage as a surrogate of earliest settlers- component revealed that the demographic events with pronounced regional variations had played pivotal role in shaping the complex net of populations phylogenetic relationship in Indian subcontinent.

ConclusionOur results suggest that tribes of southern and eastern region along with Dravidian and Austro-Asiatic speakers of central India are the modern representatives of earliest settlers of subcontinent. The Last Glacial Maximum aridity and post LGM population growth mechanised some sort of homogeneity and redistribution of earliest settlers- component in India. The demic diffusion of agriculture and associated technologies around 3 kyBP, which might have marginalized hunter-gatherer, is coincidental with the decline of earliest settlers- population during this period.

AbbreviationsAAAustro-Asiatic

IEIndo-European

DRDravidian

TBTibeto-Burman

kyThousand Years

kyBPThousand Years Before Present

yBPYears Before Present

mtDNAMitochondrial DNA

rCRSRevised Cambridge Reference Sequence

npNucleotide Position

PCRPolymerase Chain Reaction

MPDMean Pairwise Differences

AMOVAAnalysis of Molecular Variance

MRCAMost Recent Common Ancestor

MCMCMarkov Chain Monte Carlo

SDStandard Deviation.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2148-8-230 contains supplementary material, which is available to authorized users.

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Author: Satish Kumar - PBSV Padmanabham - Rajasekhara R Ravuri - Kiran Uttaravalli - Padmaja Koneru - P Aditi Mukherjee - B Das -

Source: https://link.springer.com/article/10.1186/1471-2148-8-230



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