Integration of chromosome set manipulation and transgenic technologies for fishes.

Chromosome set manipulation techniques have significant implications for research of transgenic fish. Gynogenesis can be used to generate isogenic lines, to map genes in relation to their centromeres, and to produce fish carrying extra chromosome fragments of foreign origin. Androgenesis can be used to produce isogenic lines and to recover strains from cryopreserved sperm. Triploidy can be induced in fish with heat or pressure treatment of fertilized eggs and by crossing tetraploid individuals with normal diploids. Triploid fish are typically effectively sterile. Triploid interspecific hybrids are usually more viable than the corresponding diploid hybrids. Given concerns about potential reproduction of transgenic fish in the wild, induced triploidy could facilitate application of transgenic technologies in some situations.