Transfer of Foreign DNA into Aquatic Animals by Electroporation

Abstract

Aquatic animals into which a foreign gene or a non-coding DNA fragment is artificially introduced and integrated in their genomes are called transgenic aquatic animals. Since 1985, a wide range of transgenic aquatic animal species have been produced mainly by microinjecting or electroporating homologous or heterologous transgenes into newly fertilized or unfertilized eggs and sometimes, sperm (for review, Chen and Powers, 1990; Hackett, 1993; Chiou et al., 2005). To produce a desired transgenic aquatic animal species, several factors should be considered. First, could the reproduction cycle of the aquatic animal species under consideration be completed in captivity? Second, a specific gene construct must be designed based on the special requirements of each study. For example, the gene construct may contain an open reading frame encoding a gene product of interest and regulatory elements that regulate the expression of the gene in a temporal, spatial and/or developmental manner. Third, an efficient method for delivering the transgene construct needs to be identified. Fourth, since not all instances of gene transfer are efficient, a screening method must be adopted for identifying transgenic individuals. Since the development of the first transgenic fish in the mid 1980s, techniques of producing transgenic aquatic animals have improved tremendously. Among different methods for delivering gene constructs into aquatic animals, the electroporation method is considered to be the simplest but efficient method of gene delivery. In recent years, transgenic aquatic animals have been produced as valuable models for different disciplines of biological research as well as human disease modeling. In addition, transgenic technology has been used to produce aquatic animal species with beneficial traits, such as enhanced somatic growth and disease resistance, for