Mechanisms of Sex Determination in Fish: Evolutionary and Practical Aspects

The mechanisms of sex determination in fish are extremely diverse, changeable, and labile. This review analyzes the possible variants of sex determination in fish, as well as the mechanisms that underlie quick changes in sex. The available data suggest that the ability to quickly change the molecular mechanisms of sex determination may frequently be adaptive in evolution and contribute to the formation of "biological" (non-crossing) species during a short time of isolation. Sex changes under the influence of external factors, even in the presence of the chromosome mechanism of sex determination, can also be regarded as aimed at the adaptation of populations and species to changing environmental factors. The implications of sex changes for fish aquaculture and for fish abundance assessment in natural populations are discussed. This is also essential to creating monosex fish cultures that are characterized by accelerated growth rates. Knowledge of the sex-determination mechanisms can also be useful for invasive species control.