INTRODUCTION In the Japanese frog Rana (R.) rugosa the androgen receptor (AR) gene on the W chromosome (W-AR) is barely expressed. Previously we showed that incomplete female-to-male sex-reversal occurred in Z-AR transgenic female frogs. To date, however, there is no report showing that AR with androgens can determine genetically programed male sex fate in any vertebrate species. Here, we exami...

Over the past 40 years, gonadal sex differentiation in teleost fish has been studied from histological and physiological viewpoints, for its application in fisheries. The morphological characteristics of gonadal sex differentiation in teleost fish were discussed in Section 2, and a summary of sexual processes, such as gonadal sex differentiation and sexual maturation in triploid salmonid fishes...

Background In mammals, a single exon gene SRY on the Y-chromosome is activated in the XY gonadal primordium and initiates a cascade of molecular and morphological events leading to testicular differentiation. SRY-encoded protein (SRY) is a transcription factor harboring a HMG-box DNAbinding motif that upregulates SOX9, which encodes another transcription factor sharing the DNA binding motif wit...

In mammals, male sex determination is governed by SRY-dependent activation of Sox9, whereas female development involves R-spondin1 (RSPO1), an activator of the WNT/beta-catenin signaling pathway. Genetic analyses in mice have demonstrated Sry and Sox9 to be both required and sufficient to induce testicular development. These genes are therefore considered as master regulators of the male pathwa...

Xenobiotics suspected of being estrogenic-the PCB aroclor 1242 and the pesticides toxaphene, dieldrin, p,p'-DDD, cis-Nonachlor, trans-Nonachlor, p,p'-DDE, and chlordane-were examined for their ability to override a male-producing incubation temperature and result in female hatchlings in the red-eared slider, a turtle with temperature-dependent sex determination. Compounds were assayed in the en...

To identify novel genomic regions that regulate sex determination, we utilized the powerful C57BL/6J-Y(POS) (B6-Y(POS)) model of XY sex reversal where mice with autosomes from the B6 strain and a Y chromosome from a wild-derived strain, Mus domesticus poschiavinus (Y(POS)), show complete sex reversal. In B6-Y(POS), the presence of a 55-Mb congenic region on chromosome 11 protects from sex rever...

Complete sex reversal of fish is accomplished routinely in aquaculture practices by exposing fish to exogenous sex steroids during gonadal differentiation. A variety of environmental chemicals are also active at sex steroid receptors and theoretically possess the potential to alter normal sexual differentiation in fish. However, in controlled environmental chemical exposures to date, only parti...