Induced Gynogenesis In Brown-marbled Grouper(Epinephelus Fuscogutatus)

Groupers, the rare tropical sea fish, have formed a large-scale breeding industry in Guangdong, Fujian, Hainan and Taiwan provinces in recent twenty years. Because of the bastard domestic mode, there are many problems involving groupers industry, including the decline of genetic diversity and frequent disease, which become the bottleneck restricting to the sustainable development of the industry. The choice of breeding strategy becomes the key solution to the problems of grouper breeding. Groupers are hermaphroditic fish, which take too long time to mature. Artificial gynogenesis is a highly-efficient means of producing offspring, especially when applied for long breeding cycle fish, such as groupers. One generation of gynogenesis provides equivalent results as9-10generations of line inbreeding.In this study, brown-marbled grouper (Epinephelus fuscogutatus) had been studied for artificial gynogenesis, microsatellite markers identification and chromosome karyotype. The specific studies are as follows:1. E. fuscogutatus eggs were activated by UV-irradiated sperm of giant grouper (Epinephelus lanceolatus) and duplicated by cold shock with seawater. The results showed that high percentages of meiotic gynogenetic diploids were achieved (63.2%�0.9%). The optimal dose of UV-irradiation for genetically inactivating giant grouper sperm was determined to be7-8mJ/(s� cm2) for3.5min. The eggs were cold shocked in5-7?sea water for10min at6min post-fertilization with irradiated giant grouper sperm.2. Microsatellite markers were used to analyze diploid gynogenetic fish. The markers showed that there was no genetic contribution from the paternal genome at loci Mbo048?Mbo061?GAA-1?CA-2?PmO2and RH-GATA-003.3. Chromosome karyotype analysis were used to analyze diploid gynogenetic fish. The results showed that the grouper had a diploid chromosome number of48and its karyotype formula was48t, NF=48. The48chromosomes were identical to the modal diploid karyotype study of E. fuscoguttatus.The ability to establish pure groups of meiG brown-marbled grouper should be a valuable contribution to both E. fuscogutatus genetics and breeding and sex development research in hermaphroditic fish.