Microsatellite Diversity in Andhra Pradesh, India: Genetic Stratification Versus Social Stratification

Abstract

DNA samples of 948 individuals belonging to 27 populations from southern Andhra Pradesh were analyzed for nine AmpFlSTR Profiler Plus loci. The nature and extent of genomic diversity within and between these populations have been examined with reference to socioeconomic and geographic affiliations. The results suggest that the average heterozygosity is uniformly high in these populations (Ͼ0.80) and that the patterns of allele distributions are similar across the populations. The value of the coefficient of gene differentiation and the AMOVA and structure analysis results suggest that these populations are highly homogeneous. The neighbor-joining tree constructed using either D A or F ST distances suggests no intelligible pattern of population clusters based on ethnohistoric or geographic affiliations. All these observations suggest either a common recent origin of these populations or extensive gene flow across the populations that erased the original genetic differences. Given strict endogamy, the latter explanation can hold only if there has been unauthorized or unrecognized gene flow transecting the social boundaries. Nevertheless, the regression plot of average heterozygosity versus distance from the centroid (R ii), based on Harpending and Ward's (1982) model, and the genetic distances computed between different hierarchical groups within Andhra Pradesh tend to support this conjecture. Overall, the results suggest lack of a significant degree of genetic stratification that is consistent with social stratification in Andhra Pradesh. Furthermore, the neighbor-joining tree based on comparative data from other Indian and continental populations brings out a single and compact cluster of all the Andhra populations that is clearly separated from the rest.

Quantitative trait loci at the 11q23.3 chromosomal region related to dyslipidemia in the population of Andhra Pradesh, India

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Study of DYS 390 Polymorphism among Khatri Population of Punjab in Comparison to Other Indian and World Population

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Design and Clinical Characteristics of a Homogeneous Schizophrenia Pedigree Sample from Tamil Nadu, India

“…The study primarily consists of pedigrees from a single caste group, the Tamil Brahmin, from which we exhaustively recruited ASPs and trios within the defined study region. Subsequently, we expanded the core sample to include other caste groups living in and around Chennai [30]. Population genetic studies supported this ascertainment strategy, demonstrating (i) low genetic differentiation among Tamil castes (R ST 00.96% for 45 autosomal short tandem repeat (STR) markers) [14], where R ST is the proportion of allele size variance between populations [31]; and (ii) genetic differentiation of these groups from other continental world populations demonstrated by greater genetic distance estimates (D sw ) [32] between all Tamil castes and both European and East-Asian subjects, compared to distances between individual Tamil castes, based on 45 autosomal STRs [14].…”