FERNANDINO Juan Ignacio
congresos y reuniones científicas
Amh (anti-müllerian hormone) gene is involved in the process of testis differentiation of Patagonian pejerrey (Odontesthes hatcheri)
HATTORI, R.S.; OURA, M.; JUAN IGNACIO FERNANDINO; STÜSSMANN, C.A.; MANUEL SOMOZA, GUSTAVO; YOKATA, M; WATANABA, S
Simposio; International Symposium in Sex Determination and Gametogenesis in Fish: Current Status and Future Directions.; 2008
Anti-müllerian hormone/Müllerian inhibiting substance (AMH/MIS) plays a key role in the formation of the urogenital system of reptiles, birds, and mammals, by causing the regression of the müllerian ducts in males. Although these structures are absent in fishes, recent studies have unraveled evidences that AMH also plays key roles in testis development of teleost species. In this context, we isolated the AMH gene and analyzed its expression in the Patagonian pejerrey with the aim of clarify its role during gonadal sex differentiation in this species, which have reported thermolabile sex determination (TSD) as well as a sexlinked marker. Fertilized eggs from a single cross were incubated and hatched at 21ºC and the larvae were reared at the same temperature until 12 weeks. Gene expression analysis was performed by in situ hybridization (ISH), RT-PCR, and Real-Time RT-PCR in embryos and gonads of larvae of known genotypes (XX and XY) that were sampled at various developmental stages. The caudal fin of each individual was used for sex genotyping using the SNP sex-linked marker. RT-PCR and Real-Time PCR revealed the presence of AMH transcripts in fertilized eggs from 2 days after fertilization (daf) with increasing expression levels reaching a peak at 10 weeks after hatching (wah). Sexually dimorphic expression was detected in the gonads of 1wah larvae and transcripts were localized in somatic cells of the primordial testis. The strongest ISH signals were concentrated in somatic cells in the medullar area of the gonad, suggesting a possible role in efferent duct formation. These results show that AMH may play a crucial role in testis development at very early developmental stages in Odontesthes hatcheri.