684a - 684a: Phenogenetics of Blood Group Specificity in Man

Blood group antigens are usually inherited as simple Mendelian traits and the current opinion regards them as the immediate product of one corresponding unit of inheritance, in accordance with the template theory of gene action. Actually blood group antigens are complex macromolecules and their serological specificity derives from relatively simple chemical groupings; thus the question arises whether one unit of inheritance is directly responsible for the synthesis of the macromolecule as a whole, or of only some serologically significant groupings.In regard to ABO and Lewis blood groups and soluble substances the available biochemical and genetical data suggest that: 1. more than one serological and genetical specificity may be carried by the same macromolecule (A and B, A and H, A and Lewis); 2. the final product is at least in some instances reached through a series of metabolic steps (the synthesis of H, controlled by the Xx locus, is necessary for the action of the AB genes) ; 3. interaction of genes at independent loci may induce a new serological specifity (X + Sec + Le = Leb).