Linkage Disequilibrium between ABO and Rh Loci in Barak Valley Populations vis-�-vis a Few Exotic Populations

Abstract

From a study of 28 human populations, linkage disequilibrium (LD) between ABO and Rh blood group loci in human genome were estimated using two different statistic of population genetics viz. D and Q. In general, the haplotypes iRh+ and iRh- were, on average, 2 to 3-fold and 1.1 to 1.8-fold more frequent respectively than the corresponding expected haplotype frequency in the populations under study. Expected haplotype frequencies were calculated for each population assuming equal frequencies of alleles at ABO and Rh loci. The observed frequency of IARh+ haplotype was more or less close to the expected frequency (0.165). The haplotypes IARh-, IBRh+ and IBRh- were less frequent than expected in the populations. The D value for haplotype iRh+ was positive for all the populations suggesting preponderance of this haplotype and hence non-random association between ABO and Rh loci. Q is a single measure of LD and suitable for estimation of LD between loci having multiple alleles. Q value ranged from 2.18 (Finland) to 8.07 (Hongkong). High LD, indicated by high Q, between ABO and Rh loci was observed in the populations of Hongkong, BV Muslims, Saudi Arabia, BV Hindus, India and Iceland. But the populations of Finland, Austria, Estonia, Poland and Israel showed low LD revealed by low Q between ABO and Rh loci.