Chromosomal mapping of the blood group genes.

The assignment of blood group loci proceeds more slowly than that of biochemical markers, since it depends largely on pedigree analysis and these studies take longer to achieve significance than some of the rapid modern methods. However, seven structural blood group loci ABO, MNSs, Rh, Fy, Sc, Xg, and Ch--Rg are confidently assigned, and four more provisionally or tentatively sited. Other loci are recognized as part of linkage groups that will help in the eventual assignment to their chromosomes. There is little linkage information, and no assignments, for other independent loci involved in the expression of the ABO, Pl, Rh, and Lu loci.