ИСТИНА

To obtain meiotic gynogenesis in Acipenser ruthenus, the spermatozoon genes were inactivated by UV radiation, inseminated eggs were exposed at 36.9-33.8оС for 2 minutes. The use of sperm from morphologically different A. schrenckii provided an opportunity to easy identify gynogenetic progeny by morphological study. 15 gynogenetic specimens were grown to the 6-month age. Cytological studies of their gonads revealed 80% of females and 20% of fishes with sex differentiation not started; however, according to anatomical data last fishes are males. In the case of disomic inheritance (most probable for 120-chromosome sturgeons), female heterogameity, and the absence of crossing-over between sex chromosomes, the sex ratio in gynogenetic progeny should be 1(WW)♀:1(ZZ)♂ (WW-superfemales will be viable). In the case of crossing-over, females will be dominated by the appearance of WZ♀. To date, the data on sex determination are obtained for three 120-chromosome species: A. stellatus (Badrtdinov et al. 2008), A. ruthenus (this study) and Polyodon spathula (Shelnon & Mins 2012), and for A. ruthenus x A. huso hybrid (Omoto et al. 2005). All of them have female heterogameity. All-male gynogenetic progeny of A. stellatus indicates the absence of crossing-over and non-viability of WW-superfemales. The sex ratio in other gynogenetics is about 1♂:4♀.