A review of artificial gynogenesis in the Caspian Sea sturgeons

In sturgeon, female-sex rearing is economical and gynogenesis induction is one of the ways to achieve it. In gynogenesis, an egg develops without the genetic influence of the male, or on the other words, it is a method of reproduction in which the offspring are formed exclusively from the genetic information of the mother. In this technique, the sperm used must be genetically inactivated. Rays such as X-ray, gamma (ionizing rays) or ultraviolet (UV) rays can be used to inactivate the sperm. Activation of embryonic development with genetically inactive sperm has resulted in the production of haploid eggs, which in order to diploidize must use physical shocks during the second meiotic division or the first mitotic division. In this case, all the offspring have maternal inheritance. It depends on the type of sex determination system, that amount of production of female offspring is determined. In sturgeons, the offspring sex determination is the responsibility of the mother, so by inducing gynogenesis, both males (lower ratio) and females (higher ratio) are produced. Accordingly, artificial gynogenesis could increase both the caviar production and prevent the extinction of these valuable species.