Molecular systematics and phylogeny of Rutilus s. str. (Teleostei: Leuciscidae) at the southern part of Caspian Sea

Rutilus is one of the most important genera of the Leuciscidae family, whose members are distributed from Eastern Siberia to Western Europe. It has always been difficult for researchers to identify the species and populations of this genus due to the similarity of morphologic characters and the existence of intermediate populations. Although several studies conducted base on morphology characters of members of this genus, the molecular systematic and phylogeny of Rutilus in the southern Caspian Sea have not been studied. Therefore, in order to investigate the status of Rutilus members in the southern Caspian Sea, a study was performed using the COI gene sequence. Samples of members of this genus were purchased from the of beach of Bandar-e-Turkmen, Bandar-e-Gaz, Babolsar, Nour, Ramsar, Bandar-e-Anzali and Astara. After amplifying the COI gene, the fragment was sequenced. Using the sequences results and other sequences in the NCBI gene bank, phylogeny trees were plotted by the Bayesian inference method, Maximum likelihood estimation, and haplotype network. According to the results, the sequenced specimens from the southern basin of the Caspian Sea were placed in the R. frisii clade. Also, the presence of R. rutilus and R. kutum species in the studied areas was not confirmed. Due to the insignificant difference in COI gene and phenotypic diversity, it seems the differences due to ecological plasticity, tolerance to salted waters coupled degrees of salinity, having resident and migratory populations among members of this genus.