Distances électrophorétiques entre les cinq espèces de babouins du genre Papio basées sur les mobilités des protéines et enzymes sériques

The baboons of the Papio genus have for a long time been divided into five distinct species, P. papio, P. anubis, P. cynocephalus, P. ursinus and P. hamadryas, with the latter being classed apart from the other four. This classification has been based on morphological, sociological and biogeographical grounds. Recently, however, the five forms have been considered as merely different sub-species of a polytypic species. This view has been supported by calculations of genetic distances between four of the species, the data being based on the electrophoretic polymorphism of the erythrocytic enzymes. The overall distances calculated are not greater than those obtained for the subspecies of other vertebrate genera. The present article shows that P. papio and P. anubis are indistinguishable in this respect, but that differences between the four species are observed by measurements of the electrophoretic mobilities of at least seven proteins and serum enzymes, namely: albumin, transferrine, esterases C₁ to C₄ and alkaline phosphatase. The apparent contradiction between these results may be explained in two ways. Firstly, the genetic distances correspond to a relatively low level of individual heterozygosity. The second, and principal reason, is that the proteins and serum enzymes present in the various tissues have evolved much more rapidly with time than the intracellular erythrocytic enzymes. Seven proteins can therefore be used to distinguish between the four species. The differential electrophoretic mobility data have been treated by the classical methods of multidimensional analysis to give a planar projection of the distances between the species. This shows P. hamadryas to be the most distinct form. The results obtaind agree with those derived from studies of the immunology of the transferris, the isoantigens, and from DNA hybridization experiments.