Dopamine D2 receptor and ankyrin repeat and kinase domain containing 1 genes among the two linguistically distinct tribal populations of Ranchi district, Jharkhand, India.

In the recent years, haplotype studies have emerged as a critical tool for studying the human migratory patterns. Dopamine D2 receptor (DRD2) and Ankyrin Repeat and Kinase Domain Containing 1 (ANKK1) genes, which also bear specific clinical implications in various neuropsychiatric and behavioural/addictive disorders, are significant nuclear DNA markers for studying human genome diversity. The present study was conducted in order to understand the distribution pattern of the three DRD2 and ANKK1 TaqI sites and also the frequencies of their haplotypes among Oraons (n = 48) and Mundas (n = 50)--the two linguistically distinct tribal population groups of Jharkhand. The phylogenetic inference was drawn through the statistical comparisons of the present DRD2 and ANKK1 TaqI site data with the available data from population groups belonging to other parts of India and also rest of the world (ALFRED Database). All the three TaqI sites were found to be polymorphic among Oraons and Mundas with relatively high average heterozygosities. Oraons exhibited a comparatively higher frequency of the ancestral B2D2A1 haplotype (0.356) than the Mundas (0.193). Significant and higher linkage disequilibrium (LD) values between all three sites were observed among Mundas which is indicative of admixture, whereas Oraons exhibited non significant and low LD values. The presence of ancestral haplotype B2D2A1 in higher frequency and lower and non-significant LD among Oraons suggest that they might be the older inhabitants in the region though the major limitation of the study is small sample size which might have introduced bias in the accuracy of the calculated pairwise LD for the three polymorphic sites.