Effect Of Heterologous Sperm On Gynogenetic Pengze Crucian Carp (Carassius Auratus) And Isozyme Analysis Among Three Strains Of Crucian Carp

GUI Miao (College of Life Science, South China Normal University, Guangzhou 510631)Pengze crucian carp, Carassius auratus of Pengze, is a unique model system for studying evolutionary genetic and selective breeding, owing to its specific genetic background and reproductive modes. The species exists a triploid bisexual population, female outnumbering male by about four to one in their natural habits, and reproduces by gynogenesis. Surprisingly, heterogeneous sperm from other species of fish, besides stimulating and activating development of the egg, are able to contribute to the phenotype of gynogenetic offspring, that is allgynogenesis.The patterns of expressions in five isozymes (EST, MDH, ME, SOD and LDH) were investigated in the embryogenetic stages of gynogenetic crucian carp(Carassius auratus of Pengze) activated by homogenous and heterogeneous sperms. Five isozymes (EST, MDH, ME, SOD and LDH) of different tissues, serum and muscle protein of Bumper crucian carp (C. auratus of Pengze (3-)XCyprinus acutidorsalis ( & )), its female parent crucian carp (C. auratus of Pengze) and male parent seap carp (C. acutidorsalis) were also analyzed with vertical polyacrylamide gel electrophoresis.The patters of MDH, LDH and SOD showed apparent differences between the embryo activated by homogenous sperm and that activated by heterogeneous sperm. The main differences in MDH exist in hatching stage, which showed two more bands(MDH4' and MDH5') in the isozyme pattern of embryo activated by heterogeneous sperm than that activated by homogenous sperm. The main differences in LDH exist in five stages from middle-gastrula to muscle construction, which showed four more bands (LDH9', LDH10', LDH 11' and LDH 12') in the isozyme pattern of embryo activated by heterogeneous sperm than that activated by homogenous sperm. The main differences in SOD exist in two stages-6-from darkly-pigmented eye to hatching, which showed two more bands(SODl' and SOD2') in the isozyme pattern of embryo activated by heterogeneous sperm than that activated by homogenous sperm. Meanwhile, the other two isozymes (EST and ME) detected in this paper did not show apparent differences between the embryo activated by homogenous sperm and that activated by heterogeneous sperm. Furthermore, the speed of development of the embryo activated by heterogeneous sperm is slight faster than that activated by homogenous sperm. By comparing the growth of the offspring of Pengze crucian carp produced by various sperm stimulating, the results comfirmed that the growth effects exist in the offspring activated by heterogeneous sperm, and discovered that seap carp can finely activated the gynogenesis of Pengze crucian carp.The results showed that the electrophoretogram patterns of isozymes, serum and muscle protein of Bumper crucian carp were the same as those of its female parent and significantly different from its male parent. It is speculated that the function of heterogeneous sperm was only in DNA level and not behave on the isozyme expression of grown progeny.Isozymes in different tissues of three stains of crucian carp were studied comparatively. The results indicated that Pengze crucian carp is different from Silver crucian carp in biochemical level, they probably came from different region. The electrophoretogram of Pengze crucian carp and Silver crucian carp all included the basal patterns of Wild crucian carp. EST isozyme patterns between Pengze crucian carp and Wild crucian carp is similar especially among the patterns of several isozyme. It is speculated that Pengze crucian carp and Silver crucian carp were all origined from Wild crucian carp. The relations between Pengze crucian carp and Wild crucian carp is closer than that of Silver crucian carp and Wild crucian carp.