A new genomic polymorphism of Rh-polypeptide genes.

To determine which Rh-polypeptide genes are related to which Rh (rhesus) antigens, genomic DNAs prepared from donors of ten kinds of different Rh phenotypes were analysed by Southern hybridization method using two probes for the 5' moiety and 3' moiety of an Rh-polypeptide cDNA. A polymorphism for the Rh blood-group system was observed with BamHI, HindIII, PstI and EcoRI restriction endonucleases between genomic DNAs from the RhD-positive and RhD-negative individuals as has previously been reported. Further study showed an additional genomic polymorphism. The new polymorphism was detected between the RhC/c phenotypes unrelated to the RhD/d phenotypes with RsaI restriction endonuclease using the probe for the 5' moiety of Rh polypeptide cDNA. A 1.9 kb RasI restriction fragment was missing in the genomes from individuals with the RhC phenotypes. However, this fragment was present in the genomes of Rhc phenotypes and in its half dose in the genomes of RhCc phenotypes. These results clearly demonstrate a new polymorphism between the RhC/c phenotypes regardless of the RhD-positive and RhD-negative phenotypes, and it is predicted that the Rh polypeptide genes encoding RhD, RhC/c and RhE/e antigens are different.