Genetic variation in the bottlenose dolphin Tursiops truncatus along the KwaZulu/Natal coast, South Africa

Genetic variability and differentiation of the bottlenose dolphin Tursiops truncatus population along the KwaZulu/Natal coast was examined by horizontal starch gel electrophoresis. In all, 19 loci, encoding 14 allozymes, were resolved for 40 specimens. Three loci (15,8%) were polymorphic. Average heterozygosity for the population corresponded with values determined for other delphinid populations. However, the heterozygous state of the enzyme G6PD was only found in female bottlenose dolphins, suggesting that this enzyme may be X-linked in delphinids. Cluster analysis indicated a trend towards a north-south dichotomy in the KwaZulu/Natal population, a result supported by previously reported pollutant data as well as greater variability and smaller genetic distances in the southern cluster. However, non-significant FST values implied a lack of true genetic structure in the KwaZulu/Natal population. It is proposed that the annual influx of bottlenose dolphins from the Eastern Cape coast, in response to the m...