Fig. 3. vab-1 and sax-3 display non-allelic non-complementation in axon guidance; DIC (left) and fluorescence (right) images of the head region are shown. (A) +/mIn1GFP `wild-type' adults stained with the vital dye DiI to visualize the amphid head neurons (red). The mIn1GFP marker was used to visualize the pharynx (green). The amphid neuronal cell bodies are close to the terminal bulb (TB) of the pharynx. The amphids send out axons that first migrate ventrally and then dorsally to project and terminate in the nerve ring (arrow), which is posterior to the metacorpus (MC). (B) +/mIn1GFP; sax-3 mutants display a highly penetrant anterior axon displacement. The axons project anteriorly past the metacorpus, arrow. In addition, sax-3 amphid cell bodies are often misplaced more anteriorly. (C) vab-1/mIn1GFP; +/sax-3 double heterozygous animals display axon guidance defects (25%) similar to those of sax-3 homozygous animals.