Fig. 2

Identification of secondary sex characteristics (SSCs). A–D SSCs of wild-type females: body shape/body color (A), anal fin and anal papilla (B), caudal fin (C) and pectoral fin (D) without breeding tubercles. E–H SSCs of wild-type males: body shape/color (E), anal fin (F), caudal fin (G) and pectoral fin (H). The arrow indicates a large number of breeding tubercles, which occur specifically in males. H–K SSCs of cyp17a1^+/+; tdrd12^−/−: body shape/body color (H), anal fin (I), caudal fin (J) and pectoral fin (K) with breeding tubercles. L–O SSCs of cyp17a1^−/−: body shape/body color (L), anal fin (M), caudal fin (N) and pectoral fin (O) without breeding tubercles. P–S SSCs of double KO mutants: body shape/body color (P), anal fin (Q), caudal fin (R) and pectoral fin (S) without breeding tubercles. mpf: months post-fertilization; PF: pectoral fin; AF: anal fin; CF: caudal fin. 6 individuals of each genotype were detected in this assay