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We report single nucleotide polymorphisms (SNP) at the two sites each of NPY and DRD2-Taq1 loci among the 28 populations from southern parts of Andhra Pradesh, India. The average allele frequency at these sites in these populations categorized into upper, middle and lower ranking castes, Muslims and tribes were also carried out in order to test if there is any trend in the allele frequency of some of these SNPs that are implicated in alcoholism. This was felt important as some of these hierarchical low ranking groups and tribes traditionally are known for addictive behavior, especially to alcohol , as against the prohibitive norms among most of the higher ranking castes. The trend in average allele frequency although suggests some association with these traditional behavioral patterns, the case control studies are required before inferring the exact nature of this association. The bivariate plot between the NPY-C and Taq1A1 mean allele frequencies in the 28 populations and the lack of significant association between the genotypes of these two SNPs at the individual level rules out any possibility of co-adaptation between these two alleles, despite both being somewhat implicated in alcoholism.

KEYWORDS ADH2 & ADH3; Indian castes and tribes; social hierarchy; lifestyles; alcoholism ABSTRACT We report single nucleotide polymorphisms (SNPs) at the four sites in ADH2 and ADH3 genes among the 28 populations from southern parts of Andhra Pradesh, India. A total of 1048 individuals belonging to 28 endogamous populations distributed in the contiguous areas of the 6 southernmost districts of Andhra Pradesh were enrolled for the present study. Genotyping involved PCR and sequencing. We sequenced exon 3 and 9 of ADH2 and exon 8 of ADH3, besides the ADH2 3'UTR- rs17033 (72 bases down stream of ADH2 Arg369Cys). The two sites of ADH2 (Arg47His and Arg369Cys) are found to be completely monomorphic showing only Arg47 and 369Arg (ADH2*1 allele), the remaining two sites were polymorphic. None of the 28 populations of this study deviated significantly from Hardy Weinberg Equilibrium proportions. The allele frequencies do not show any clear trend across socioeconomic groups. The degree of heterogeneity in the genotype frequencies among the hierarchical groups is significant for Ile349Val (df = 12; χ2 = 22.050) and not for the 3'UTR rs17033 (df = 6; χ2 = 9.765). The haplotype distribution among the hierarchical groups is found to be highly homogeneous and statistically nonsignificant (χ 2 = 0.248, df = 18). Linkage disequilibrium does not exist between the two-polymorhic loci. The results were interpreted in the light of cultural patterns of the Indian hierarchical society.