Studies On Artificial Breeding And Development Of Microsatellite Loci In The Veined Rapa Whelk Rapana Venosa

Rapana venosa belongs to Mollusca, Gastropoda, Muricoidea, Rapana. R.venosais a predatory marine gastropod native to the coastal waters of China, Korea, andJapan, and has been transported around the globe since the1940s. R. venosa is acommercially important mollusk species in China, but has been suffering from severepopulation decline due to overexploitation and habitat destruction. For the past fewyears, artificial breeding of the R. venosa has been studied. However, the technique ofthe artificial breeding is not completely established. and is very necessary to improveit.Due to their codominant, multiallelic and highly polymorphic nature,microsatellite markers provide an ideal tool to investigate the genetic variation andpopulation structure. There is no report on the microsatellite markers of the R. venosa.The major results of the paper are listed as follows:1. Artificial breeding of the Rapana venosaIn the present study, the aims of the research were to explore the most suitablefeed for broodstock conditioning of R. venosa. Mactra chinensis were the best,followed by Perna viridis, and worst Siliqua minima with a lowest survival rate.In this study, artificial breeding of R. venosa was reported. A total of1000cocoons were recorded during our experiment. The mean length and width of thecocoons was19.80mm and2.85mm respectively, and the mean length-width ratiowas7.10. The average number of eggs in every cocoon was1304. A relation betweenthe health condition of breeder and the cocoon size was founded. By comparing thesizes of the egg cages and eggs, and condition of female parents, we found that femaleparents is the most important factor determining the sizes of the egg cages and eggs.Beginning from the cleavage, larvae characteristics at different developmentstages were observed. Larvae’s preference for substratum during settlement andmetamorphose was studied, and the corrugated plate was shown to be the suitable substratum finally. The data of temperature, salinity and optimal food obtained in ourstudy will be important reference in the future study.To illuminate the effect of KCl on larvae set and metamorphose, a double factorexperiment with5different KCl concentrations and5different deal time wasconducted. The result showed that the optimal concentration was1810-3mol/L andthe optimal deal time was10hours for this concentration.To study the effect of animal diet on larval metamorphosis,5kind of diet werecompared each other. Results showed that there were a largest number of larvae oncorrugated plates. The information on optimal food and substrate of larvae duringsettlement and metamorphosise, and transformation of feeding habit will benefit forthe establishment of artificial breeding in R venosa.2. Isolation and characterization of microsatellite loci of the Rapana venosaSamples of R venosa were captured from Qingdao, China. The enrichedmicrosatellite library was built by magnetic bead hybridization selection andbiotinylated (CA)15and (CT)15probes. A total of23polymorphic microsatellite lociwas isolated and characterized for population studies. The number of alleles per locusranged from3to17, and the observed and expected heterozygosities varied from0.167to1.000and from0.455to0.924, respectively. These microsatellite loci will beuseful tools for fisheries management and conservation, and reproductive biology forthis species.