The genetic diversity and genetic structure of four Silurus glanis Linnaeus 1758 populations were evaluated using ISSR markers in the northwestern Iran to understand the potential benefit of these populations for breeding purposes and/or any necessary conservation programs. Four populations were evaluated from three geographic regions; two populations from the Urmia Lake basin (one from the Mahabad Dam Lake and the other from the Zarineh River), one population from the Anzali Lagoon basin and one population from the Aras River basin. ISSR primers produced 99 discernible bands in the four populations. The Anzali Lagoon population showed lower level of diversity than other populations. The percentage of polymorphic bands and unbiased expected heterozygosity were 98.99 and 0.342, representing a considerable genetic variation through the studied populations. The analysis of molecular variance results showed significant variations among geographic regions (P<0.001). Comparison of pairwise ΦPT values revealed significant differences between geographic regions; however, the Zarineh and the Mahabad populations within the Urmia Lake basin did not show any significant difference (P<0.05). The northwest Iranian S. glanis populations were gathered into two discrete groups after constructed unrooted neighbour-joining tree based on Nei’s unbiased genetic distance. One group formed by the Anzali population and other by the Mahabad, the Zarineh and the Aras populations. The Mantel test revealed significant correlation between genetic distance and geographical distance matrices. The present study can suggest reasonable potential benefits of these populations for breeding purposes, while the Anzali Lagoon population needs to be considered for any future conservation programs.
