Systematic classification of alleles of the glycophorin A (MN blood group) gene

Ten alleles (five M and five N alleles) of the MN blood group system with normal antigenicity were found by sequencing the glycophorin A (GPA) gene. This study demonstrates the systematic classification of these alleles to major or minor variations of the standard alleles. GPA-specific fragments ranging from 150 to 3.8 kb in length were amplified from the templates, and exons 1–7 and introns 1–6 were sequenced. The data were analyzed phylogenetically to classify these alleles into major groups or clusters. The ten alleles were grouped into four major clusters M10X (M101–M103), M20X (M201 and M202), N10X (N101–N104) and N20X (N201), where X represents a digit indicating minor variations. This grouping was supported by phylogenetic analysis. The cluster system of GPA alleles is highly informative for genetic screening.