Molecular analysis of the genetic differentiation among Aphanius fasciatus populations captured from tunisian coastal and estuary sites

Aphanius fasciatus is a cyprinodont distributed in the salty coastal water of the central and eastern mediterranean sea and occasionally in internal fresh water. in this study,we investigated the genetic structure of three populations of the killifish a. fasciatus captured from tunisian coast. the genetic diversity of mitochondrial nadhdehydrogenase subunit 1 (965pb) was addressed on 17 specimens of three populations of aphanius. fasciatus.. phylogenetic analyses (maximum likelihood (ml) and neighbour-joining (nj)) were fully congruent and demonstrated the occurrence of two main groups or clades. the first clade comprises coastal populations (luza and sfax sites) while the second includes a population from estuary (oued hamdoun site). the analysis of molecular variance (amova) showed that the percentage of variation among groups is considerably higher (72.8%) than within populations (34.32%). the overall fst value (0.65; p=0.01) supports an extensive genetic structure of the two clades. these data represent an attempt towards the geographic diversification of a. fasciatus and provide new insights for the knowledge of genetic structural patterns and the evolutionary processes occurring in these species. copyright 2012 zoological society of pakistan.