Y chromosome-linked amhy gene and sex determination of atherinopsid species

HATTORI, R.S.; MURAI, Y.; OURA, M.; MASUDA, S.; MAJHI, S.K.; SAKAMOTO, T.; FERNANDINO, J.I.; SOMOZA, G.M.; ALMEIDA-TOLEDO, L; STRÜSSMANN, C.A.

Buenos Aires

Simposio; 7th International Symposium on Fish Endocrinology; 2012

In many vertebrates, gonadal sex determination follows a sequence of geneticallyprogrammed events. However, only a few sex determining genes have beendescribed and the mechanisms of genotypic sex determination in teleosts stillremain elusive. In order to clarify such process in atherinopsids we conductedtranscriptomic analyses of several sex-related genes during early sex differentiationin Odontesthes hatcheri. Those studies lead to the identification of the Y-specificanti-Müllerian hormone (amhy), a paralogue of the autosomal amh (amha). Codingand non-coding sequences of amhy were used for chromosome mapping. mRNAexpression was analyzed by RT-PCR and ISH, and knock-down was conducted byantisense morpholinos. Amhy shared 92.2% of amino acid identity with amha and itsphysical mapping allowed the identification of the Y chromosome. Amhy transcriptswere detected from before hatching in presumptive Sertoli cells and its knockdownresulted in XY females. These findings establish amhy as a master sex-determininggene candidate in O. hatcheri. The presence of amhy has since been examined inseveral congeners species and matched the phenotypic sex in half of them. Theseresults suggest that amhy may be important for testis determination in some but notall Odontesthes species.