Fig. 3. Male tail defects of plx-1 mutant, mab-20 mutant and Ce-sema-1 (RNAi) animals. All animals contain him-5. Anterior is towards the left. Arrows indicate ray 1 and arrowheads indicate ray 2. (A,B) DIC photomicrographs of ventral views of (A) a control and (B) a plx-1(nc37) mutant adult tail. In B, ray 1 on both sides show displacement defects but to different extents; the right ray 1 (arrow) is located outside of a fan (class I defect) and the left ray 1 remains in a fan (class II defect). (C-G) DIC photomicrographs of lateral views of a control (C), plx-1(nc37) (D), mab-20(bx24) (E), Ce-sema-1a, Ce-sema-1b (RNAi) (F) and mab-20(bx24); plx-1(nc37) (G) animal. In the mab-20(bx24) animal (E), ray 1 fused to ray 2, and rays 3-5 fused together. The Ce-sema-1a, Ce-sema-1b (RNAi) animal (F) shows displacement of ray 1 similar to the plx-1(nc37) animal (D). In the mab-20(bx24); plx-1(nc37) animal (G), ray 1 is displaced anteriorly and ray 3 fuses to ray 4. Scale bars: 20 µm.