Fig. 3

Morphology of primary sex characteristics (PSCs) of the mutants. A–A″) Normal testis of a control male. Anatomical view (A); histological view of the whole testis (A′, testis outlined in white); enlarged view shows a well-developed testis with various developmental stages of germ cells, such as spermatocytes (SC), spermatogonia (SG), sperm (SP) and somatic cells (ST) in the testis (A″). B–B″ Atrophic testis of a tdrd12^−/− fish; the testis lacks germ cells and is surrounded by fatty layers. Anatomical view (B), histological view (B′, outlined in white) and enlarged view (B″). C–C″ Testis of a cyp17a1^−/− fish. Anatomical view; C histological view (C′, testis outlined in white); enlarged view shows the testis with various developmental stages of germ cells, such as SC, SG, sperm and some ST (C″). D–D″ Atrophic testis of a double knockout (KO) fish. Anatomical view (D); histological view (D′, testis outlined in white); enlarged view (D″) shows an atrophic testis similar to that of the tdrd12^−/− fish. 6 fish of each genotype were used in this assay