Differentiation of isolated, threatened fish populations in dolomitic waters of the transvaal, South Africa, by polyacrylamide gel electrophoresis (page) of total cellular proteins

Abstract

Isolated, small ecosystems associated with springs and sinkholes in semi-arid regions of the western Transvaal, South Africa, are under threat as there is a growing need to tap the dolomitic waters which maintain these systems. Part of a programme to demonstrate that these systems are unique and worthy of conservation is to characterize fish populations genetically and morphologically. The data presented here indicate that the populations of Tilapia sparrmanii from the Malemani and Molopo Oog springs and the Wondergat sinkhole differ from each other genetically when examined using polyacrylamide gel electrophoresis (PAGE) of total soluble protein. The outgroups in the analysis were Tilapia guinasana, a closely related substratum-spawning cichlid endemic in Guinas sinkhole, Namibia, and Pseudocrenilabrus philander, a distantly related mouthbrooder of the haplochromine lineage. The findings of this study were (a) that PAGE can distinguish between species and between conspecific populations and (b) that the isolated populations of the dolomitic ecosystems of the western Transvaal are unique and should be conserved.