A comparison to neutral and adaptive genetic diversity of cultured populations of silver carp (Hypophthalmichthys molitrix) in Iran

During the last decade studying of adaptive markers in contrast to neutral types, has been welcomed. The most famous member of these genes, MHC, along with 8 microsatellites was analyzed in spatial groups (138 individuals) of silver carp from different provinces including Golestan, Mazandaran, Guilan, Khouzestan in addition to line samples imported from China. Mean allelic richness, expected heterozygosity and Shannon Index estimated for microsatellites as 5.04, 0.682 and 1.32, and MHC as 4.21, 0.674 and 1.23, respectively. About 2% and 3% of differentiation among populations was observed for microsatellites and MHC respectively. No significant bottleneck signals were detected in all of studied populations. Given to significant excess heterozygosity revealed in both of MHC and microsatellites in contrast to hardy-Weinberg model and proportional higher degrees of differentiation between populations in MHC, a balancing selection function can be attributed to this locus. Finally, it can be concluded that studied populations in this research have been able to maintain their genetic diversity in these loci through several stages of propagation in the hatcheries. Higher allelic richness of MHC-DAB loci in Chinese samples beside high levels of heterozygosity and diversity within population can be considered as the strength of this group.