RESUMO
The revelation of leptin action mechanisms has led to various attempts to establish the association of polymorphisms in the leptin gene with obesity-related phenotypes. But, outcomes have been contradicting, which made the information on the role of the leptin gene in regulating the mechanism of pathophysiology of obesity inexplicable. Moreover, none of the studies are known to have similar implications on the Indian population. To address such contradictions, our study aims to evaluate the association of leptin gene polymorphism with obesity and leptin levels in a South Indian Population. A total of 304 cases (BMI≥27.5) and 309 controls (BMI≤23) from local inhabitants of Mysore, Karnataka were recruited for the study. The leptin gene variants rs7799039, rs2167270 and rs4731426 independently, as well as in 4 haplotype combinations, were found to be significantly associated with the risk of obesity. An increasing trend in BMI and leptin levels was observed with every addition of A and C minor alleles of exonic variant (rs2167270) and intronic variant (rs4731426) respectively. However, only AA genotype of SNP rs7799039 was positively associated with BMI. None of the SNPs were associated with fat percentage and waist to hip ratio. On a whole, this data suggests that the common polymorphisms in the leptin gene are strong predictors of obesity and leptin levels in South Indians.
RESUMO
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.
