RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM OF HLA-DR AND HLA-DQ ALLOTYPES IN 4 ENDOGAMOUS GROUPS OF WESTERN INDIA

HLA-DR and HLA-DQ allele frequencies in four populations (Brahmin, Mar atha, Gujarati Hindu Patel, and Parsi) of Bombay, western India, were analyzed using TaqI RFLPs detected by the cDNA probes DRB, DQB, and DQ A. Although the overall differences in the HLA-DR and HLA-DQ genotype frequencies among the populations were not statistically significant, several population-specific haplotypes were significant. Multivariate analyses using data on 2 loci (HLA-DR and HLA-DQ) produced a meaningfu l pattern of genetic affinity and differentiation that parallels the a nalysis made when frequency data on 23 loci (21 blood group and protei n loci and 2 class II antigen loci) are used. The R(ST) for class II l oci was 0.006; the genetic differentiation increased to 0.01 when data on 23 polymorphic loci were analyzed. The genetic affinity analysis s hows the isolated nature of the Parsi and close genetic affinity betwe en the two local populations of Bombay. Although the RFLP technique ha s several limitations compared with newly defined PCR-based methods, o ur analysis shows that the RFLP technique is still a useful adjunct me thod for studying HLA polymorphisms for which only limited data from t he populations of the Indian subcontinent are available.