Population structuring of a species provide basic information for biological conservation. We investigated the genetic structure of seven populations of Rana pseudodalmatina, an endemic species of the Ranidae inhabiting the Hyrcanian forests in northern Iran, based on the genetic variation of two partial mitochondrial DNA sequences (16SrRNA and cytochrome b genes). Molecular genetic analyses revealed remarkable variation among populations of R. pseudodalmatina. The phylogenetic trees clearly indicated two distinct haplogroups, which largely corresponded to their geographic locations. A strong population structure was found (ΦCT = 0.559, P = 0.027) with high haplotype diversity (Hd = 0.88) and low nucleotide diversity (π = 0.0041). Analysis of molecular variance (AMOVA) indicated that most of the observed genetic variation (55.92%) occurred between the two haplogroups. Also, Mantel tests revealed a significant correlation between geographic and genetic distances (R2 = 0.33, P = 0.005). Finally, the star-like topology of haplotype network and also neutrality testsprovide strong evidence for population expansion in two haplogroups. All the findings of the present study, suggest a strong evidence for past expansion of isolated populations of R. pseudodalmatina, which their isolation could be largely attributed to rising level of the Caspian Sea during last glacial periods in the Pleistocene.
