Genetic divergence among and within four Italian populations of Aphanius fasciatus (Teleostei, Cyprinodontiformes)

Abstract

Due to the natural fragmentation of its habitats, Aphanius fasciatus, a Cyprininodontid living in coastal brackish-water habitats, is distributed discontinuously with considerable isolation of its populations, and characterized by a high degree of osteological and genetic differentiation among them. The genetic relationships in four different Italian populations were studied using the control region (D-loop) mitochondrial DNA sequence and the polymorphisms generated by RAPD-PCR. The results revealed a well-defined genetic structuring, that was also confirmed by the high Gst and Fst values, and a close relationship between the populations of Ganzirri and Lesina, as well as the isolation of the other two Sicilian populations. Moreover, with respect to the mitochondrial DNA analyses, the total genetic variance was higher among populations, but lower in the case of the RAPD polymorphisms.