Study On The Polymorphism Of Genomic Microsatellite And Isozymes In Onychostoma Sima

Onychostoma sima is a good kind of freshwater fish in the main current and branches of the Chinese Yangtze River. It has great nutritional and economic value. Many people like to eat it for its deliciousness.However,the amount of wild Onychostoma sima have rapidly reduced, due to the ecological impact and human overfishing.In this study, isozymes and the polymorphism of genomic microsatellite markers in Onychostoma sima was performed to provide the evidence for the identification of germplasm.The genomic DNA was extracted from the caudal fin of Onychostoma sima by Phenol-Chloroform method.Primers of microsatellite DNA for this research was derived from Procypris rabaudi,from which pra20EF5701、pra02EU541506、pra36EU541508、 pra67EU541509、pra107EU541514、pra117EU541515were screened for their clear and single band from the polymerase chain reaction (PCR). Primers of pra67EU541509and pra117EU541515are highly polymorphic.The number of alleles for these two loci are8and4, respectively. Observed and expected heterozygosities were0.75、0.83and0.583、0.736, respectively.The polymorphism information content (PIC) are0.766and0.652, respectively. So they belong to high degree of polymorphic markers. These results suggested that these two microsatellite loci could be useful for the assessment of heredity multiplicity and analysis of population structure in Onychostoma sima.Isozymic patterns of three isozymic Lactate dehydrogenase(LDH), Esterase(EST) and Malate dehydrogenase(MDH) in six tissues (such as brain, eyes, heart, liver, kidney and muscle) of Onychostoma sima were determined by vertical poiyacrylamide gel electrophoresis (PAGE). The result indicated that these three isozymic systems had distinct tissue-specific expression in the different tissues. Ldh-AB3and Ldh-B4isozymic bands were expressed dominantly in the other four tissues except the liver and the muscle, while Ldh-A4and Ldh-A3B isozymic bands were in the kidney and muscle. The number of EST isozymic band in the liver are the most, and its bands are the strongest. The weaker activity of ESTwere showed in both of eyes and muscle. There are only s-MDH found in the liver and the kidney, with strong activity.