Genetic structure and microgenetic differentiation among populations of Terai belt of Bihar, India

Distribution of ABO blood groups, Rh, PTC taste ability and colour blinness was investigated among twelve endogamous populations of Terai belt (Indo-Nepal border) of Bihar, who belonged to different castes and ethnic groups with different migrational history. The phenotypic and gene frequencies of four common loci show wide differences between the populations. In general, group B is dominant over group A, but in four populations (Badhiya, Kulhayya, Mushar and Tharu) group O was prevalent. Rhnegative frequency was highest among Bania and lowest in Tharu. Frequency of non taster was highest among Tharu and lowest in Oraon. The incidence of redgreen blindness was lowest in Santal and highest in Mushar. The pooled heterozygosity was highest (0.545) for ABO locus and lowest for colour blindness (0.055).The average heterozygosity value varies in between 0.228 among the Tharu and 0.420 among the Bania. The studied populations share low Gst value i.e. 0.020, which is almost negligible. The dendrogram depicts bifurcation of the population groups into two lines: one line leading to Tharu alone and the other line leads to Santal and other populations. The other line bifurcates again into Muslim and a bunch of populations. This bunch of populations includes Mushar, Rajbanshi, Chamar, Brahmin, Oraon, Munda, Dhobi, Bania, Kulhayya. Muslims share more or less proximal ancestor. From the genetic distance analysis there is some evidence of close genetic relationship among the population groups belonging to same region, irrespective of their caste, religion, linguistic or any other affinities.