Genetic Heterogeneity and Ethno-historical Considerations of Burusho and Balti Tribes with Regard to ABO and Rh Blood Group Alleles

regard to ABO and Rh group alleles of Burusho andBalti tribes of northern Pakistan in order to determineorigin of these populations.Methods: A prospective study was conducted fromNovember 2006 to January 2007 at Combined MilitaryHospital Gilgit in which a total of 4318 blood sampleswere taken for ABO and Rh D blood grouping. Theycomprised of 3210 samples taken from the Burusho and1008 samples of the Balti population. The method ofsampling was random. Genetic affinities and genediversity of the two populations was determined in termsof genetic distancing analysis with regards to ABO andRh loci.Results: The average ABO allele frequencies in theBurusho population were ABO*A (0.37) ABO*B (0.32)ABO*AB (0.02) and ABO*O (0.29). Similarly the averageallele frequencies of Balti population were ABO*A (0.23)ABO*B (0.31) ABO*AB (0.09) and ABO*O (0.37). In Brushoalleles frequencies for D and d of the Rh groupsystem were 0.942 and 0.0580, for Balti 0.950 and 0.500respectively for the total data. There is a marked increasein the frequency of blood group gene A in Burushopopulation and a corresponding decrease in bloodgroup gene O as we proceed from older to younger agegroups. Also there is significant divergence (p <0.05) inBurusho population for the distribution of ABO allelesfrom the general South Asiatic trend (O greater than Bgreater than A). Probably because of the relatively smallstarting value of r < 0.5 a selection took place against groupO resulting in an increase of the blood group gene A inBurusho population.Conclusion: The genetic distance analysis revealsthat the two tribes included in this study are geneticallydistant from one another and the genetic clusteringpattern correlates with linguistic/ethnic affiliation andgeographical proximity of these tribal populations to acertain extent