An application of PCR-single strand conformation polymorphism to MN genotyping

A PCR-based genotyping of MN blood group system was investigated for DNA samples taken from a population of 409 northern Japanese. DNA fragment (257bp) including exon 2 of glycophorin A (GPA) gene, in which encodes the determinants of MN antigens, was specifically amplified. On the analysis of PCR-single-strand conformation polymorphism (PCR-SSCP) for M alleles, band patterns of M G and M T were easily discriminated each other. For N alleles, three band patterns were observed, and we tentatively named these alleles as N 1, N 2 and N V. The N 1 allele appeared predominantly and N 2 had two base substitutions at 1st (C→A) and 56th (C→T) in exon 2 of N 1. The other N V, which was detected from a pair of a mother and her child, possessed a single base substitution at 23rd (A→G) in intron 2. The allele frequencies of M G, M T, N 1 and N 2 were 0.4450, 0.0978, 0.4303 and 0.0269, respectively. The polymorphism information content and the probability of paternity exclusion by this MN genotyping were estimated to be 0.5252 and 0.3219, respectively.