Genetic divergence in South African wildebeest: analysis of allozyme variability.

Genetic variability within the blue (Connochaetes taurinus) and black (C. gnou) wildebeests in South Africa was estimated from allozyme frequencies at 31 protein-encoding loci. Seven loci, Ak-1, Alb, Est-D, Icdh-1, Mpi-1, Pgm-1, and Tf, were polymorphic in the blue wildebeest, but only two loci, Est-D and Tf, were variable in its congener. Average gene diversity was H = 0.018 +/- 0.013 in the black wildebeest and was significantly smaller than that, H = 0.081 +/- 0.030, in the blue wildebeest. The reduced level of heterozygosity in black wildebeest is most likely due to a bottleneck in population size in the early 1900s. The genetic distance between the two species was 0.059 +/- 0.027, which is consistent with an estimate of low mtDNA sequence divergence found previously.