Shift of male primordial gonad replication pattern towards female by down regulation of Dmrt1bY (BrdU incorporation). Replication pattern of the primordial gonad was followed by BrdU incorporation. A: female primordial gonad phenotype at hatching stage. B: male primordial gonad phenotype at hatching stage. C, D and E: fluorescence produced by BrdU incorporation colocalizes with GFP fluorescence of primordial germ cells in the Olvas transgenic line. GFP fluorescence (C), BrdU fluorescence (D), overlay (E). F: primordial gonad phenotype at hatching stage after Dmrt1bY morpholino injection in a genetic male.