Two Melanesian antisera reacting with SsU components

Two different Melanesian antibodies demonstrated, by blocking tests and their reaction patterns, steric interaction of S, s and U components. The antigen(s) detected, designated Ux and Uz, may represent differing conformations, genetically determined, of certain U, S and s structures. Of 1,000 Caucasian bloods, 3 had very marked enhancement of Ux. Family studies are presented. In one such blood, abnormal steric interaction of D with s and U was indicated. Melanesian population studies show that Ux and Uz are among the antigens depressed in recessive ovalocytosis. The linkage disequilibria affecting MNSs and SsUz are inter-related, the associations being of SUz with Caucasian M and Melanesian N.