Gynogenesis caused by ultraviolet irradiation of salmonid sperm

Gynogenetic rainbow trout lines can be produced easily with the simple UV sperm irradiation technique detailed in this study. The dose effect on embryonic survival rate is called a pseudo “Hertwig effect” because of major differences with results of gamma irradiation: Some mixing of various karyotypes (from diploid to haploid number) were obtained with mean doses, probably because of the weak penetrating power of the ultraviolet rays. Irradiations lasting 4 minutes or more are required to produce homogeneous haploid progeny; heat shock applied to such fertilized eggs results in diploid fry of the maternal phenotype