The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage

BACKGROUND: The "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. RESULTS: The 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. CONCLUSION: Our 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

The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage

Abstract Background The "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. Results The 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. Conclusion Our 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.</p

The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage-1

PD) limits. Panel 'A'- The Bayesian skyline plot (= 10) for India total, derived from complete mtDNA sequences (= 76). Panel 'B'- The Bayesian skyline plot (= 10) for India total, derived from coding region (577–16023) mtDNA sequences (= 76). The time estimates (yBP) were calculated as per []. For comparison, the cold and arid period around the Last Glacial Maximum are also indicated on panel A & B. Panel 'C to F' shows Bayesian skyline plots (= 10) derived from complete mtDNA sequences of eastern (n = 11), central (n = 29), southern (n = 14) and western (n = 22) regions of India respectively.<p><b>Copyright information:</b></p><p>Taken from "The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage"</p><p>http://www.biomedcentral.com/1471-2148/8/230</p><p>BMC Evolutionary Biology 2008;8():230-230.</p><p>Published online 11 Aug 2008</p><p>PMCID:PMC2528015.</p><p></p

The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage-0

Ur additional complete mtDNA sequence of M2 lineage (labeled as R102, T3, T11 and T27) are acquired from published sources [] has been used for tree reconstruction. Suffixes A, C, G, and T indicate transversions, "d" signifies a deletion and a plus sign (+) an insertion; recurrent mutations are underlined. The prefix "@" indicates back mutation. The coalescent estimates were calculated as per [] and [] presented as bold and Italic respectively.<p><b>Copyright information:</b></p><p>Taken from "The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage"</p><p>http://www.biomedcentral.com/1471-2148/8/230</p><p>BMC Evolutionary Biology 2008;8():230-230.</p><p>Published online 11 Aug 2008</p><p>PMCID:PMC2528015.</p><p></p

The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage-2

Ur additional complete mtDNA sequence of M2 lineage (labeled as R102, T3, T11 and T27) are acquired from published sources [] has been used for tree reconstruction. Suffixes A, C, G, and T indicate transversions, "d" signifies a deletion and a plus sign (+) an insertion; recurrent mutations are underlined. The prefix "@" indicates back mutation. The coalescent estimates were calculated as per [] and [] presented as bold and Italic respectively.<p><b>Copyright information:</b></p><p>Taken from "The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage"</p><p>http://www.biomedcentral.com/1471-2148/8/230</p><p>BMC Evolutionary Biology 2008;8():230-230.</p><p>Published online 11 Aug 2008</p><p>PMCID:PMC2528015.</p><p></p

Updating phylogeny of mitochondrial DNA macrohaplogroup m in India: dispersal of modern human in South Asian corridor.

To construct maternal phylogeny and prehistoric dispersals of modern human being in the Indian sub continent, a diverse subset of 641 complete mitochondrial DNA (mtDNA) genomes belonging to macrohaplogroup M was chosen from a total collection of 2,783 control-region sequences, sampled from 26 selected tribal populations of India. On the basis of complete mtDNA sequencing, we identified 12 new haplogroups--M53 to M64; redefined/ascertained and characterized haplogroups M2, M3, M4, M5, M6, M8'C'Z, M9, M10, M11, M12-G, D, M18, M30, M33, M35, M37, M38, M39, M40, M41, M43, M45 and M49, which were previously described by control and/or coding-region polymorphisms. Our results indicate that the mtDNA lineages reported in the present study (except East Asian lineages M8'C'Z, M9, M10, M11, M12-G, D) are restricted to Indian region.The deep rooted lineages of macrohaplogroup 'M' suggest in-situ origin of these haplogroups in India. Most of these deep rooting lineages are represented by multiple ethnic/linguist groups of India. Hierarchical analysis of molecular variation (AMOVA) shows substantial subdivisions among the tribes of India (Fst = 0.16164). The current Indian mtDNA gene pool was shaped by the initial settlers and was galvanized by minor events of gene flow from the east and west to the restricted zones. Northeast Indian mtDNA pool harbors region specific lineages, other Indian lineages and East Asian lineages. We also suggest the establishment of an East Asian gene in North East India through admixture rather than replacement