Studies On Isozymes And Microsatellite Markers Of Inbreeding F₁ Progeny Of Artificial Gynogenetic Silver Carp (Hypophthalmichthys Molitrix)

Silver carp (Hypophthalmichthys molitrix) is one of the main-farmed freshwater fishes and possesses a large proportion in freshwater aquaculture in China. At the present, because of the lack of techniques in seed selection and protection, the natural resources of silver carp were destroyed, and the propagations in close relatives lead to the germplasm degeneration. In China, researchers have preliminarily established inbreeding F₁ progeny of artificial gynogenetic silver carp. In this paper, the isozymes and microsatellites were used to test the genetic structure.In this study, by using plane polyacrylamide gel electrophoresis, the polymorphism of muscle proteins and two isozymes including lactate esterase (EST) and dehydrogenase (LDH) from five tissues (liver, kidney, heart, eye and muscle) of gynogenetic silver carpI strain, II strain, wild silver carp, common silver carp and male carp were determined respectively. It showed that (1) The electrophorgrams of isozymes of male carp was obviously different from the others'. (2) The polymorphism of EST was detected of II strain. The proportions of polymorphic loci of liver, kidney and muscle were 0.6000, 0.3333 and 0.5000 respectively; the heterozygosity of liver, kidney and muscle were 0.7485, 0.6622 and 0.1139. (3) C band was expressed in LDH of liver, in which polymorphism was detected. (4) The differences among I strain, II strain, wild silver carp and common silver carp could not be found on the level of protein.With the SSR primers of silver carp, genetic variations of population (including effective number of alleles, gene frequency of alleles, proportion of polymorphic loci, heterozygosity, Shannon's index, Fixation index and Genetic distance) of 37 microsatellite loci were analyzed by using the method of DNA extraction, PCR amplifying, polyacrylamide gelelectrophoresis testing et al with the material of gynogenetic silver carpII strain, wild silver carp and male carp. The results revealed that: (1) male carp had PCR product with 25 pairs of primer, which proved that these primers were universal in carp and silver carp. (2) polymorphism was expressed in 25 SSR loci. The proportion of polymorphic loci (78.38% & 75.68% respectively), average observed heterozygosity (0.5108 & 0.5078 respectively), average expected heterozygosity (0.4725 & 0.4004 respectively) and Shannon index (0.834 & 0.6370 respectively) of wild silver carp and II strain showed that the polymorphism of II strain were lower than wild silver carp. (3) Fst value showed that variation was mostly due to within populations (93.25%) rather than among population (6.75%). (4) II strain in BL75 locus were completely homozygotic. (5)...