The zebrafish (Danio rerio) has become a well-established experimental model in many research fields but the loss of the primary sex-determining region during the process of domestication renders laboratory strains of zebrafish susceptible to the effects of environmental factors on sex ratios. Further, an essential husbandry aspect - the optimal rearing density to avoid stress-induced masculini...

Abstract: Fishes exhibit the greatest diversity of species among vertebrates, offering a number of relevant models for genetic and evolutionary studies. The investigation of sex chromosome differentiation is a very active and striking research area of fish cytogenetics, as fishes represent one of the most vital model groups. Neotropical fish species show an amazing variety of sex chromosome sys...

The European eel Anguilla anguilla (L.) is a catadromous fish: individuals grow and feed in brackish and fresh waters as yellow eels until sexual maturation, when they metamorphose to the silver stage and leave continental waters to reach their spawning grounds in the Sargasso Sea. Sexual maturation of European eels, as well as sex differentiation, depend upon body size rather than age, with fa...

From a classical viewpoint, sex-specific behavior and physiological functions as well as the brain structures of mammals such as rats and mice, have been thought to be influenced by perinatal sex steroids secreted by the gonads. Sex steroids have also been thought to affect the differentiation of the sex-typical behavior of a few members of the avian order Galliformes, including the Japanese qu...

In the mouse, germ cells can undergo differentiation to become either oocytes or spermatozoa in response to sex of their gonadal environment. The nature of the germ cell-intrinsic aspects of this signaling have not been well studied. The earliest known sex-specific difference in germ cells is the initiation of meiosis in female, but not male, embryonic germ cells. Experiments were performed sho...

T HIS FINAL CHAPTER AIMS to summarize the main findings of the different studies of this thesis about the neuroendocrinological factors affecting gender identity and the sexual differentiation of the brain and behavior. Methodological considerations and implications are discussed in light of the existing literature. The discussion will conclude with recommendations for the clinical practice and...

T HIS FINAL CHAPTER AIMS to summarize the main findings of the different studies of this thesis about the neuroendocrinological factors affecting gender identity and the sexual differentiation of the brain and behavior. Methodological considerations and implications are discussed in light of the existing literature. The discussion will conclude with recommendations for the clinical practice and...

Fish sex reversal is a means to understand sex determination and differentiation, but it is also used to control sex in aquaculture. This review discusses sex reversal in gonochoristic fish, with the coexistence of genetic and environmental influences. The different periods of fish sensitivity to sex reversal treatments are presented with the mechanisms implicated. The old players of sex differ...

background: disorders of sex development (dsds) belong to uncommon pathologies and result from abnormalities during gonadal determination and differentiation. various gene mutations involved in gonadal determination and differentiation have been associated with gonadal dysgenesis. despite advances in exploration of genes and mechanisms involved in sex disorders, most children with severe 46,xy ...

Sexual differentiation across taxa may be due to genetic sex determination (GSD) and/or temperature sex determination (TSD). In many mammals, males are heterogametic (XY); whereas females are homogametic (XX). In most birds, the opposite is the case with females being heterogametic (ZW) and males the homogametic sex (ZZ). Many reptile species lack sex chromosomes, and instead, sexual differenti...