TAS2R38 gene polymorphism and its association with taste perception, alcoholism and tobacco chewing among the Koraga - a primitive tribal population of Southwest coast of India

Introduction: The Koraga tribe is one of the primitive tribal populations residing in the southwest coast of India. Addiction to alcohol and tobacco chewing are most common in the Koraga population. The TAS2R38 gene variants were being associated with a variety of bitter tasting dietary foods, alcohol, and nicotine. Hence, we examined the influence of the TAS2R38 gene polymorphisms on the alcohol dependence and tobacco chewing habits among the Koraga tribal population. Methods: Volunteers (n = 296) belongs three clans (Onti, Kuntu, and Soppu) of the Koraga population recruited for the present study to analyze the PTC tasting and its association with alcoholism and tobacco chewing. Genotyping of all three variants of the TAS2R38 gene, i.e., G145C (rs713598), T785C (rs1726866), A886G (rs10246939) were performed using Sanger sequencing followed by haplotype analysis. Results: We observed the significant difference in the frequency of tasters and non-tasters among the three clans of the Koraga tribes (p <= 7.4 x 10(05)). Haplotype analysis showed the distribution of intermediate taster (PAV/AVI) (46%) and nontasters (AVI/AVI) (34%) were high among the Koraga population compared to the tasters PAV/PAV (13%). Further, there was a positive association between non-taster haplotype AVI/AVI (71.4%) with alcoholics (p-value <= 7.76061E(-08)) and the tobacco-chewers (53.0%). In conclusion, increased frequency of nontasters might have influenced the higher risk of alcohol dependence and tobacco chewing in the Koraga population.