Sexual Definition: is there a pattern in the sexuality of fish? A Revision

Abstract

The fish are found in the most diverse aquatic habitats, ranging from high altitudes the depressions far below sea level, which reflects a wide range of existing species. This condition is due to diversity genomics be enriched by the fusion of the gametes in the training of individuals and in sex determination. Of genetic recombinations, during the processes of cell division and reproductive strategies, which result in a broad adaptive plasticity, both biological and ecological. All this becomes possible through the playback, where also if there is a great diversity of forms, even if there is a pattern of sexual development as well defined as male or female in the majority of species, constituting the gonochorists, and a small fraction formed by types of reproductive unisexual sessile and hermaphrodites. The explanation of this diversity has as a basis the property of retaining the dual sexual potentiality of primordial germ cells, found in different stages in gonadogenesis, and by their ability to differentiate during the reproductive life, a biological base kept by teleosts, constituting all plasticity. For this reason, it was possible to observe species that show great stability and other very labile to change the sex throughout their life. These different forms of reproduction has its origin in the great variety of mechanisms responsible for both sex determination as to formation of patterns of sexual differentiation, which include a genetic basis, with monogenic and polygenic systems, and the influence of different environmental factors, mainly temperature and social interactions. Although the mechanisms of sex determination and differentiation are conserved in mammals and birds, in fish seem to be very unstable. This suggests that, in evolutionary terms, an accumulation of evidence of participatory process in favor of a unification of strategies that emphasize the genetic factors and the environment. In particular, it seems that the environmental factors govern the force responsible for sexual development and by developments in all levels, with the selection and genetic drift having been responsible for establishing a standard capable of characterizing the current sexual determination. Thus, the proposal would be: in what way or in what level these factors contribute to driving the evolutionary process, independent of any context and in a way wholly holistic .