Serum Transferrins in the Genus Macaca: Species Distribution of Nineteen Phenotypes

Abstract

IN the genus Macaca, rhesus monkeys show a remarkable polymorphism of transferrin, the iron-binding protein, whereas cynomolgus monkeys (the Philippines variety) show only one molecular form of the protein^1,2. Two-dimensional starch-gel immunoelectrophoresis³ was used in previous work^1,2 to determine (with the aid of a uni-specific chicken anti-human transferrin serum) the number of transferrin components in the macaque sera. Then comparative one-dimensional starch-gel electrophoresis in the tris discontinuous buffer system was used to establish the subtle differences in the mobilities of transferrin, and fifteen phenotypes² due to various combinations of eight molecular forms of the protein were detected among rhesus monkeys. These results have now been confirmed by determinations based on the iron-binding property of transferrin. We have also adopted a provisional letter system of nomenclature which has simplified identification of the macaque transferrin phenotypes, thereby making it easier to discover new phenotypes. In this connexion a re-examination of the rhesus sera and an examination of sera from additional macaque species have now revealed nineteen transferrin phenotypes, sixteen being present in the rhesus group alone.