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.

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.

Background: An early dispersal of biologically and behaviorally modern humans from their African origins to Australia, by at least 45 thousand years via southern Asia has been suggested by studies based on morphology, archaeology and genetics. However, mtDNA lineages sampled so far from south Asia, eastern Asia and Australasia show non-overlapping distributions of haplogroups within pan Eurasian M and N macrohaplogroups. Likewise, support from the archaeology is still ambiguous.

The development of chronic obstructive pulmonary disease, upon exposure to tobacco smoke, is the cumulative effect of defects in several genes. With the aim of understanding the genetic structure that is characteristic of our patient population, we selected forty two single nucleotide polymorphisms of twenty genes based on previous studies and genotyped a total of 382 samples, which included 236 patients and 146 controls using Sequenom MassARRAY system. Allele frequencies of rs2276109 (MMP12) and rs1800925 (IL13) differed significantly between patients and controls (p = 0.013 and 0.044 respectively). Genotype analysis showed association of rs2276109 (MMP12) under additive and dominant models (p = 0.017, p = 0.012 respectively), rs1800925 (IL13) under additive model (p = 0.047) and under recessive model, rs1695 (GSTP1; p = 0.034), rs729631, rs975278, rs7583463 (SERPINE2; p = 0.024, 0.024 and 0.012 respectively), rs2568494, rs10851906 (IREB2; p = 0.026 and 0.041 respectively) and rs7671167 (FAM13A; p = 0.029). The minor alleles of rs1695 (G), rs7671167 (T), rs729631 (G), rs975278 (A) and rs7583463 (A) showed significant negative association whereas those of rs2276109 (G), rs2568494 (A), rs10851906 (G) and rs1800469 (T; TGF-β) showed significant positive association with lung function under different genetic models. Haplotypes carrying A allele of rs2276109, G allele of rs1695 showed negative correlation with lung function. Haplotypes carrying major alleles of rs7671167 (C) of FAM13A and rs729631 (C), rs975278 (G), rs7583463 (C) of SERPINE2 had protective effect on lung function. Haplotypes of IREB2 carrying major alleles of rs2568494 (G), rs2656069 (A), rs10851906 (A), rs965604 (C) and minor alleles of rs1964678 (T), rs12593229 (T) showed negative correlation with lung function. In conclusion, our study replicated the results of most of the previous studies. However, the positive correlation between the minor alleles of rs2568494 (A) and rs10851906 (G) of IREB2 and lung function needs further investigation.

Dyslexia is a hereditary neurological disorder that manifests as an unexpected difficulty in learning to read despite adequate intelligence, education, and normal senses. The prevalence of dyslexia ranges from 3 to 15% of the school aged children. Many genetic studies indicated that loci on 6p21.3, 15q15-21, and 18p11.2 have been identified as promising candidate gene regions for dyslexia. Recently, it has been suggested that allelic variants of gene, DYX1C1 influence dyslexia. In the present study, exon 2 and 10 of DYX1C1 has been analyzed to verify whether these single nucleotide polymorphisms (SNPs) influence dyslexia, in our population. Our study identified 4 SNPs however, none of these SNPS were found to be significantly associated with dyslexia suggesting DYX1C1 allelic variants are not associated with dyslexia.