Polymorphism of the vitamin D binding protein (DBP) among primates: an evolutionary analysis

The distribution of the DBP (vitamin D binding protein) polymorphism is now well characterized among human populations but for primates only limited results are known. The aim of this paper is to describe the electrophoretic polymorphism of this protein among various species. Using three different electrophoretic methods, we are able to detect an unknown polymorphism and to classify the different alleles observed. These results may be used to set an international nomenclature for further comparisons. The different electrophoretic mobilities between Old and New World Monkeys show that: 1) the Cercopithecoïdea are presenting the largest genetic heterogeneity; 2) the DBP among the Galago corresponds to the lowest isoelectric points observed among Primates; 3) during the evolution from nonhuman Primates to Man, the DBP is able to keep its affinity for vitamin D derivatives despite the occurrence of significant molecular modifications; 4) among Anthropoïdea, the electrophoretic patterns of DBP are very close to the human Gc1 proteins. These results show that evolution at the DBP level can be considered as a continuous mechanism of structural modifications. A significant transition occurs during the differentiation between Cercopithecoïdea and Anthropoïdea. It is not too speculative to consider that some electrophoretic forms detected among Gorilla, Pongo, or Pan may be identical to rare variants observed among humans.