PCR-based genotyping of MNSs blood group: subtyping of M allele to MG and MT.

PCR-based genotyping of MNSs blood group system was investigated in combination with restriction fragment length polymorphism (RFLP), single-stand conformation polymorphism (SSCP) and allele-specific PCR amplification (ASPA) techniques. M and N alleles are based on three nucleotide substitutions in exon 2 and one base change (G or T) in an intron of glycophorin A locus. The latter single base change was also found among M alleles analyzed in this study, so that M allele appeared to be subdivided into MG and MT. All three alleles, MG, MT and N were identified clearly by RFLP or SSCP analysis following a single amplification. S and s alleles are based on one nucleotide substitution in exon 3 of glycophorin B gene. Genotyping of Ss blood group system was also explored by PCR-SSCP or ASPA analysis, and problems in the methods were discussed.