The kutum (Rutilus frisii kutum) is one of the economically valuable species of CaspianSea. Two different races of this fish exist in the Caspian Sea, the spring race and theautumn race. The aims of this study were to analysis the population genetic structure andgenetic diversity among and between populations of these races based on microsatellitemarkers. For this purpose, ۱۰۰ samples of adult kutum from two regions of Caspian Sea(Anzali Wetland and Shiroud River) were collected. DNA was extracted and ۳۱ pairmicrosatellite primers were used for PCR and ۱۰ made polymorphic patterns. In thisstudy ۱۹۱ alleles were observed totally. The maximum numbers of alleles (۱۸) were foundin two loci (Ca۱ and Ca۳) and the minimum number of alleles (۲) was found in MFW۱locus. The differences between both races were not statistically significant (P>۰.۰۵),neither for average number of alleles per locus nor for observed heterozygosities. Thecalculated Fst and Rst between two races was ۰.۰۵۶ and ۰.۱۵ which shows that thegenetic difference was significant (P< ۰.۰۱). Spring race in MFW۱ locus and autumn racein Lid۱ locus were at Hardy-Weinberg equation but not in other loci in both races. Thegenetic distance was ۰.۴۰۷ which indicating the greatest genetic distance between the twostudied races. The data generated in this study showed that the spring and autumn racesof kutum in two region of southern part of Caspian Sea are two independent populations.

Caspian Sea kutum, Rutilus frisii kutum, Microsatellite, Genetic structure, Population genetic