Investigation of the genetic variability in Litopenaeus vannamei shrimp, using SSR markers, in Jask port of Hormozgan province

Due to the lack of specified linage and parentage information from exotic broodstocks of Litopenaeus vannamei shrimp, in Iran, the status of genetic structure and genetic variability of this species isn’t clear. In order to estimate the current status of genetic pool and investigate the genetic variability indices, total of 30 samples from Amiri and Gorgeaj farms in Jask port of Hormozgan province, were detected with four microsatellite markers Pvan1758, TUDGLv1-3.224, TUDGLv5-7.33 & TUDGLv7-9.17. The number of alleles in every marker was 5-10; the mean number of alleles (Na) by populations ranged from 7.5 to 7.75 and their effective number of alleles (Ne) from 4.834 to 5.148. The mean value of observed heterozygosity (Ho) by populations ranged from 0.458 to 0.479, which was lower than the expected one (0.791-0.794). Observed heterozygosity values (Ho) were lower than expected heterozygosity values (He), except for TUDGLv1-3.224, in Gorgeaj population that indicating a general deficit of heterozygous types for the under studied markers. Mean polymorphism information content (PIC) in two populations based on markers (0.88), indicating the high polymorphism of studied markers. Amiri’s farm population in TUDGLv5-7.33 and Pvan1758 (P<0.001) markers; Gorgeaj’s farm population in TUDGLv5-7.33 (P<0.01), TUDGLv7-9.17 and Pvan1758 (P<0.001) markers; departed from Hardy-Weinberg equilibrium (HWE). The mean coefficient of inbreeding (FIS), 41%, and the coefficient of genetic differentiation among populations (FST), was 0.100. Using analysis of molecular variance (AMOVA), the molecular variability among (15%) and within (85%) populations were obtained. Also, values of PhiPT and Nm, 0.149 and 1.432 respectively, showed that there is moderate genetic differentiation and adequate gene flow among two studied populations. The high FIS and moderate FST highlight the importance of continuous evaluation of genetic variability in Hormozgan cultured Litopenaeus vannamei shrimp populations.