Fig. 5.

Sox100B mutant testes fail to elongate during metamorphosis. A Diagram showing stages of male reproductive tract development during metamorphosis (after Bodenstein, 1950). Testis is shaded in dark grey and genital disc derivatives in light grey. At puparium formation (left) the larval testis and genital disc are distinct. At 16 h of pupal development (middle), the testes begin to elongate towards the outgrowing genital disc. The adult reproductive tract (right), showing the characteristic coiling of the testes. B–G Pupal testes: In the wild type day 1 pupae (B) the testis has begun to elongate whereas in Sox100B mutants (C) it remains in a larval-like state. In 2 day pupae the testis of wild type (D) continues to elongate while the Sox100B mutant still remains in a larval-like state (E). In wild type day 1 pupal testis, staining with anti-Ems reveals the pigment cells (F). In the Sox100B mutants, the number of Ems-positive pigment cells is considerably reduced and staining appears weaker (arrows) than in wild type (G).