Studies on the Dombrock blood group system in non-human primates

The Dombrock blood group system consists of five distinct antigens: two antithetical antigens, Do^a and Do^b, and three high-frequency antigens: Gy^a, Hy, and Jo^a. Although the prevalence of Do^a and Do^b in different populations makes them useful as genetic markers, the scarcity of reliable antibodies to these antigens has prevented this potential from being realized. The gene (DO; ART4) encoding the Dombrock glycoprotein has been cloned and sequenced, and the molecular bases of the various Dombrock phenotypes have been determined. The purpose of this study was to perform DNA-based assays on the DO homolog in non-human primates to determine the degree of conservation in the DO gene. Murine MoAbs to Dombrock protein were developed by standard hybridoma technologies and used to test RBCs from non-human primates by hemagglutination. PCR-RFLP analysis for the six singlenucleotide polymorphisms (SNPs) that have been defined in human alleles were performed on DNA extracted from fresh or frozen blood samples from numerous non-human primates. Hemagglutination tests with six MoAbs to the Dombrock glycoprotein revealed distinct epitopes on RBCs from the non-human primates. The gorillas and orangutans had the same PCR-RFLP digestion pattern for the six SNPs studied as chimpanzees. Old world monkeys (macaques) were identical at nucleotides (nt) 323, 350, 624, and 793 with the chimpanzees, and at nt 898 the digestion pattern was the same as for the HY1 allele in humans. For the new world monkeys (tamarins and squirrel monkeys) the digestion pattern was conserved for nt 793 but different for nt 624; the other SNPs could not be determined because there was no amplification. The presence of epitopes recognized by the MoAbs and PCR-RFLP results among the non-human primates shows considerable conservation of the DO gene. The difficulties we encountered with the amplification of DNA from the non-human primates lower in the phylogenetic tree are probably due to divergence in sequence.