Biochemical genetic variation between four populations of Labeobarbus polylepis from three river systems in South Africa

Abstract

The genetic variation within four Labeobarbus polylepis populations from both river and dam environments in the Limpopo, Incomati and Phongolo River systems was studied. Gene products of 22 enzyme-coding loci were resolved using horizontal starch gel electrophoresis. Fourteen (64%) of the 22 loci were monoallelic in all populations. Levels of polymorphism (P_0.95) ranged between 9.1% and 22.7%. The heterozygosity varied from 0.028 for the Westoe Dam population (Phongolo River system) to 0.093 in the Spekboom River population (Limpopo River system). The genetic distance, F_ST and N_EM values, as well as pair-wise contingency χ² analyses indicate a lack of gene flow between populations, as expected for isolated fish. Evidence of foreign genetic material in one population was also observed.