NEW RARE VARIANTS AND INTERPRETATION OF THE GENETIC DIVERSITY AT THE GROUP-SPECIFIC COMPONENT (GC) LOCUS IN POPULATIONS OF INDIA

As part of our ongoing genetic studies, 2635 samples from 30 populatio ns of the Indian subcontinent have been analyzed for GC subtype variat ion. Several rare variants were found and have been characterized usin g isoelectric focusing in 3 M urea and with an immobilized pH gradient and by comparison with known standards. Six new variants, 1A33, 2A22, 2A23, 2A24, 1C56, and 1C59, have been discovered in geographically an d ethnically distant populations of the Indian subcontinent, Variants 1C11 and 1C21 have been reported previously in the French population a nd variant 1C36 has been reported in Nepalis, but all three variants w ere observed for the first time in the populations of India. The distr ibution of the rare variants in the Indian subcontinent was examined f or anthropological usefulness for differentiation of Indian population s. The data for GC allele frequencies from 144 populations of India we re compared for geographic and ethnic variation. A high frequency of t he GC1F allele was observed in populations of eastern India, and vari ous ethnic groups from the eastern zone were clearly differentiated fr om similar ethnic populations from the rest of India. GC2 allele freq uency data were further correlated with various geographic and climati c variables, such as longitude, latitude, sunshine, solar radiation, a nd mean annual temperature. A significant positive correlation between GC2 frequency and latitude was observed. The GC*2 allele frequency s howed a dine increasing from south to north. Significant negative corr elation was also observed between GC2 frequency and sunshine, solar r adiation, and mean temperature. A possible interpretation for selectio n of the GC2 allele in areas with low levels of insolation is provide d.