Molecular genotyping of ABO blood groups in some population groups from India

Background & objectives: Indian population is characterized by the presence of various castes and tribal groups. Various genetic polymorphisms have been used to differentiate among these groups. Amongst these, the ABO blood group system has been extensively studied. There is no information on molecular genotyping of ABO blood groups from India. Therefore, the main objective of this study was to characterize the common A, B and O alleles by molecular analysis in some Indian population groups. Methods: One hundred samples from the mixed population from Mumbai, 101 samples from the Dhodia tribe and 100 samples from the Parsi community were included in this study. Initially, the samples were phenotyped by standard serologic techniques. PCR followed by single strand conformational polymorphsim (SSCP) was used for molecular ABO genotyping. Samples showing atypical SSCP patterns were further analysed by DNA sequencing to characterize rare alleles. Results: Seven common ABO alleles with 19 different genotypes were found in the mixed population. The Dhodias showed 12 different ABO genotypes and the Parsis revealed 15 different ABO genotypes with six common ABO alleles identified in each of them. Two rare alleles were also identified. Interpretation & conclusions: This study reports the distribution of molecular genotypes of ABO alleles among some population groups from India. Considering the extremely heterogeneous nature of the Indian population, in terms of various genotype markers like blood groups, red cell enzymes, etc., many more ABO alleles are likely to be encountered.