Androgenesis and Gynogenesis

Androgenesis and gynogenesis are two forms of uniparental inheritance used in fish genetics and breeding. Gynogenesis produces offspring from the maternal genome alone: eggs are activated by UV-irradiated or chemically inactivated sperm that contributes no DNA, and the diploid chromosome set is restored by cold, heat, or pressure shock; the result is fully homozygous or mitotic clones of the mother. Androgenesis is the mirror process, developing offspring solely from the paternal genome after the egg's chromosomes are inactivated. The main commercial application of gynogenesis is rapid inbred line production and doubled-haploid technology: within two generations it yields fully inbred lines that make QTL mapping, marker validation, and hybrid vigor estimation far more precise. Androgenesis is rarer in practice but enables preservation of a dead male's genome by cloning from his sperm. Both techniques require precise control of shock timing (typically 20 to 40 minutes after activation at 25 to 42°C or 400 to 800 atmospheres depending on species) and verified by DNA fingerprinting, since low rates of paternal leakage or shock failure produce unexpected heterozygotes. These tools sit at the research frontier connecting sex determination systems, triploidy, and genomic selection in advanced breeding programs.