It can also occur artificially by exposure to endocrine disruptors such as pollutants, including herbicides, which can act as estrogen promoters or inhibitors, for instance by altering aromatase expression.
In fish, primary sexual fate can be susceptible to alteration by hormones exposure and multiple environmental factors, such as population density, water pH, or temperature.
Although it is not a reversal of sex, simultaneous hermaphrodism is beneficial for low-density populations as it allows for an increase in conspecific mating opportunities overall.
[12] [13] Within the clown fish populations, males develop bi-sexual gonads—mature testis and immature ovaries—while the dominant females only possess ovaries.
Some fish species are capable of this sex change due to the presence of both ovaries and testis, with only one gonad actively producing gametic cells at a time.
Producing a monosex fish population can improve product quality and therefore generates higher financial profit.
[24] Research [25] in wild populations of the North American green frog has demonstrated that sex reversal is common.
[28] Sex reversal has been documented in detail in wild populations of the central bearded dragon Pogona vitticeps, and in the eastern three-lined skink Bassiana duperreyi.
[29][28][30] Further, there are certain primitive reptiles (some chelonians, some crocodilians, and one lizard species) that undergo Temperature-dependent Sex Determination (TSD) during their egg incubation (a form of ESD).
Aromatase inhibitors injected into chicken eggs before the gonadal differentiation stage induce testis development in ZW embryos.
Sex reversal in mammals has been documented in domestic species such as cattle, water buffalo, horses, dogs, cats, pigs, goats, etc.
[38] Natural sex reversal without disruptive effects on fertility has been documented in several rodents, including Myopus schisticolor, Dicrostonyx torquatus, Akodon, Mus minutoides, Microtus cabrerae.
The development of an ovary and female phenotype in an individual with XY chromosomes represents the instance of sex reversal in mammals.
For instance, exposure to estrogen during critical periods of development can interfere with normal hormone levels and can cause sex reversal phenotypes.
Understanding sex reversal in mammals is crucial for wildlife conservation efforts, particularly in species facing threats such as habitat loss, and pollution.
[43] Furthermore, sex reversal can lead to behavioral adaptations within mammalian populations as individuals navigate their altered reproductive roles and social dynamics.
Research findings have demonstrated changes in mating behaviors, dominance hierarchies, and social interactions among individuals with sex reversal phenotypes.
The evolutionary significance of sex reversal and its impact on population dynamics and social structure can be studied by understanding the mechanism of behavioral adaptations.