Transgenesis and its Applications in Aquaculture

Abstract

The main transgenesis techniques which are successful in introducing exogenous genes into fish are microinjection and electroporation. Genes are introduced into one-celled embryos as well as oocytes. Microinjection is the more established method but it depends on individual treatment of the egg. Electroporation, on the other hand, is a mass method only recently shown to be effective. Other transfer techniques, such as those using sperms, liposomes, microprojectiles, embryonic stem cells and retroviruses as the vehicle, have also been reported to produce transgenic fish. Most transgenic experiments are at present conducted on finfish, and hardly any on other aquatic organisms like invertebrates except for sea urchins and, more recently, abalones. The genes with potential transgenic applications in aquaculture which have been shown to be effective in fish are the growth hormone and the anti-freeze genes. The potentials of manipulating reproduction, sex, coloration, disease resistance and other phenotypes are discussed. Studies on eco­logical, social and ethical issues of transgenic research and applications to animals in general and to fish in particular, are also reviewed.