The Study On The Gonad Development Of Transgenic Grass Carp By HU-IFN-α & Its Internal Heredity In Transgenic Grass Carp

Grass carp is one of our country's major aquatic raised varieties, but its vulnerability to diseases costs the whole industry of fresh water cultivation hundreds of millions yuans annually, of which the hemorrhagic virus is of the most serious threat. So the research on disease-resistant breed of grass carp has continuously being the very focus in the aquatic development. In the initial stage, routine hybridization and the selective pressure breeding are adopted, while the period of the later 50s and early 60s of last century also witnessed the fully application of cell engineering technology on the grass carp disease-resistant researches. However, these breeding technologies have differently some serious weaknesses such as breeding cycle period being too long and heredity of good characters being unstable. Now, with the development of DNA-recombination technology, a real foundation has been established to achieve the goal, futhermore a new way of orientation-breeding varieties is being explored.In 1998, by adopting the technology of molecule recombination, our subject team successfully cloned the coding sequence of Hu-IFN-a gene into the downstream of carp B-actin gene promoter to build up the recombination gene of Hu-IFN- a which can be expressed in the fish body. Then, by the use of the micro- injection technology, the reorganized Hu-IFN- a gene was injected into the grass carps' fertilized eggs at its 1-2 cell period to cultivate the trans-Hu-IFN-. gene grass carp. The result shows that the newly cultivated grass carp has an improved character of resistance to hemorrhage virus, 66% higher than that of the control grass carp. As a new kind of transplanted gene, whether the Hu-IFN-. influences the gonadal development and hatching process of fish and its heredity and expression on fish's F1 generation need futher research. This article will focus on the very aspects as follow:1. In order to research the impact of Hu-IFN-a on the growth of grass carp, tissue sections examination is carried out by the use of gonads at different developmental stages from the transgenic grass carp and the corresponding parts from the control grass carp. Result shows that Hu-IFN-a has no significant impacts on fish's gonadal development and hatching process.2. Three hundred and twenty-eight tails of trans-Hu-IFN-a grass carps are randomlyselected to test the target gene's expression level in the F1 generation by using the method of ELISA. Result reveals that the expression level is 52.1%, a less satisfactory one.3. By the application of the method of PCR, the positive rate of the transgenic HU-IFN-a inherited to the Fl generation was tested, and the result is at a rate of 53.8%.4. GCRV991 is vaccinated into the bodies of the Fl generation of transgenic grass carp to test its ability to resist the grass carp hemorrhage virus, the result showed the ability of the transgenic grass carp has dramatically improved by 41.9% than that of the control grass carp.