Investigation on genetic structure of Russian sturgeon (Acipenser gueldenstaedtii) populations of the north (Volga River) and south Caspian Sea (coasts of Iran and Turkmenistan) using microsatellite techniques

A total of 28 specimens of adult Russian sturgeon brood fish from the Volga River (Astrakhan, Russia) and 42 specimens from the south Caspian Sea (coastline of Iran and Turkmenistan) were collected. About 2g of fin tissue was stored in 96% ethyl alcohol and transferred to the genetic laboratory of the International Sturgeon Research Institute. Genomic DNA was extracted using phenol-chloroform method. The quality and quantity of DNA was assessed by Agarose gel electrophoresis and spectrophotometry. Polymerase Chain Reaction (PCR) was conducted using eight pairs of microsatellite primers and its products were electrophoresed using 6% polyacrylamide gel followed by silver nitrate staining. Allele sizes were measured in all populations, then genetic parameters were calculated using Gen Alex program and the phylogenetic relationship was determined and drawn using TFPGA program. A minimum of 10 and a maximum of 21 alleles were identified per locus and the observed heterozygosity ranged between 0.50-0.96 and the expected heterozygosity was 0.74-0.90 with an average of 0.68. Hardy-Weinberg equilibrium was observed at Ls-19, Ls-39 loci, but showed disequilibrium in other loci. FST index between Volga and South Caspian Sea samples was 0.031. The genetic similarity and distance was 0.661 and 0.414, respectively. Results of the present investigation indicate that there are no significant differences between the south Caspian Sea Russian sturgeon specimens