title: Sex determination in annual fishes: Searching for the master sex-determining gene in Austrolebias charrua (Cyprinodontiformes, Rivulidae).
abstract: Evolution of sex determination and differentiation in fishes involves a broad range of sex strategies (hermaphroditism, gonochorism, unisexuality, environmental and genetic sex determination). Annual fishes inhabit temporary ponds that dry out during the dry season when adults die. The embryos exhibit an atypical developmental pattern and remain buried in the bottom mud until the next rainy season. To elucidate genomic factors involved in the sex determination in annual fish, we explored the presence of a candidate sex-specific gene related to the cascade network in Austrolebias charrua. All phylogenetic analyses showed a high posterior probability of occurrence for a clade integrated by nuclear sequences (aprox. 900 bp) from both adults (male and female), with partial cDNA fragments of A. charrua from juveniles (male) and the dsx D. melanogaster gene. The expressed fragment was detected from blastula to adulthood stages showing a sexually dimorphic expression pattern. The isolated cDNA sequence is clearly related to dsx D. melanogaster gene and might be located near the top of the sex determination cascade in this species.
authors: Sección Biología Celular , Facultad de Ciencias, Universidad de la República , Montevideo , Uruguay .
authors: María José
authors: MJ
authors: Arezo
authors: Sección Biología Celular , Facultad de Ciencias, Universidad de la República , Montevideo , Uruguay .
authors: Nicolás
authors: N
authors: Papa
authors: Sección Genética Evolutiva , Facultad de Ciencias , Universidad de la República , Montevideo , Uruguay .
authors: Verónica
authors: V
authors: Guttierrez
authors: Sección Genética Evolutiva , Facultad de Ciencias , Universidad de la República , Montevideo , Uruguay .
authors: Graciela
authors: G
authors: García
authors: Sección Biología Celular , Facultad de Ciencias, Universidad de la República , Montevideo , Uruguay .
authors: Nibia
authors: N
authors: Berois
keywords: annual fish; development; doublesex gene related sequence; sex determination