Models for gsdfX and gsdfY transcriptional modulation by Dmrt1 and Wt1(-KTS). Due to opposite responsiveness to Dmrt1 and Wt1(-KTS) after the Y-specific hAT element insertion into the gsdfY promoter (A), gsdfX and gsdfY exhibit very early sexually dimorphic expression patterns (B). This example illustrates how sexually dimorphic expression of gsdfY and gsdfX are under the dependence of non-dimorphically expressed regulators (Dmrt1 and Wt1a, for instance). Hence, sexually dimorphic expression of gsdfY and gsdfX could depend on regulators that are not themselves dimorphically expressed.