Zebrafish (Danio rerio) Gynogenetic Production by Heat Shock: Comparison Between Mitotic and Meiotic Treatment

Inbred species are useful resources for a variety of biomedical research applications. To create isogenic zebrafish, it is feasible to stop meiosis II (repeatedly) or mitosis (two times) in a haploid embryo by applying pressure or by delivering a heat shock, respectively. In this study, to improve the repeatability, we suggest a less complicated approach based on sperm ultraviolet-C (UV-C) exposure for a shorter period followed by heat shock at various temperatures, eliminating the use of pressure in meiotic therapy since heat shock is more accessible to laboratories. In this study, the survivability rates of meiotic (Mei) and mitotic (Mit) gynogenesis offspring produced by various combinations of irradiation (28.5, 105, and 210 mJ/cm²) and temperature (Mei: 40.40°C, 40.60°C, or 40.90°C; Mt: 41.40°C, 41.90°C, or 42.45°C) were compared with diploid (C) and haploid (H) controls. Our findings demonstrated that 40.60°C and 41.90°C were the most suitable temperatures to produce meiotic and mitotic gynogenesis, respectively, whereas 28.5 mJ/cm² was more successful in ensuring haploid embryos. As a result, we deduced that meiotic gynogenesis produces more viable offspring than the mitotic approach and requires a lower temperature to maintain the second polar body.