Evolution model for generation of GPIIIa allelic variants.

(A) Comparison of selected regions of human GPIIIa with homologous regions on nonhuman primates and other species. The high-frequency allele of human GPIIIa (GP3A*01) as well as nonhuman primates carry the same amino acids at residues 33, 40 143, 407, and 489. (B) Evolutionary model of human platelet alloantigens on GPIIIa. The frequencies of HPAs in the white population are shown.