The Sox9 and Cyp19a1 expression change in response to Amh knockdown. (A and B) qRT-PCR of Sox9 and Cyp19a1 in control ZZ, ZZ + Amh-RNAi, and control ZW gonads of stage 25, showing significantly reduced Sox9 expression and increased Cyp19a1 expression in Amh-deficient ZZ gonads. Data are shown as means ± SD. N ≥ 3. *** P < 0.001. (C) Double immunofluorescence of SOX9 and CTNNB1 in sections of control ZZ, ZZ + Amh-RNAi, and control ZW gonads of stage 25. SOX9 protein expression almost disappeared in Amh-deficient ZZ gonads. Bar, 50 μm. RNAi, RNA interference.