Genetic structure of the killifish Aphanius fasciatus, Nardo 1827 (Teleostei, Cyprinodontidae), results of mitochondrial DNA analysis

Aphanius fasciatus is a cyprinodont distributed in the salty coastal water of the central andeastern Mediterranean Sea and occasionally in internal fresh water. In this work, the authorshave investigated the genetic structure of eight populations of the killifish A. fasciatus fromSardinia and Sicily. The comparison of the mtDNA control region of 237 individuals revealeda total of 49 haplotypes. Several unique haplotypes were present in each population, and nocommon haplotype was found among Sicilian and Sardinian populations. Almost all Sardinianpopulations shared a common haplotype, and indeed the four Sicilian populations examined didnot share any as determined by the parsimony network analysis. The analysis of molecularvariance showed that the percentage of variation among populations is much higher than withineach population of A. fasciatus. The overall FST value is very high (078) and supports anextensive genetic structure of the populations. The observed genetic differentiations ofA. fasciatus populations were discussed taking into account the palaeogeographic and palaeoclimaticevents that interested the Mediterranean area from Miocenic to Pleistocenic age. Theresults provide new insight into the knowledge of the pattern of genetic structure and ofevolutionary processes occurring in this species.