Founder effects explain the distribution of the HLAA1-B17 but not the absence of the A1-B8 haplotypes in India

Abstract

The HLA system may play an important role in natural selection processes through its involvement in immune response and because of the HLA association of some diseases. Linkage disequilibrium in the HLA system poses many interesting questions. India. a melting pot of races and cultures in sympatric isolation, provides an ideal opportunity to study these aspects. Linkage disequilibrium and haplotype data are valuable in the comparison of various populations. An analysis of the available HLA A-B haplotype data for the Indian population documents the heterogeneous nature of the latter: each endogamous caste group, major group or even regional group has its characteristic haplotype profile. The haplotypeA1-B17 is present in most Indian populations but A10-B8 occurs mostly in North India: this may be a consequence of founder effects. The haplotype Al-B8 a typical Caucasian haplotype, is absent in the Indian subcontinent: this may be due to the selective disadvantage A1-B8 confers in the Indian environment. The different regional and caste groups of India possessing diverse haplolype combinations provide an ideal opportunity to evaluate the selective values of these haplotypes and to study human immunogenetics.