Fig. 1. Whole-mount ISH of RH2 and M/LWS opsin probes to embryonic or larval eyes of zebrafish. (A–D) Lateral views of embryonic eyes (nasal side to the left and ventral to the bottom) hybridized with the RH2-1 CDR probe, where progress of the gene expression is staged as follows: stage 1, expression is detected in a patch of ventronasal retina; stage 2–3, another patch appears in nasal retina and the two fuse to fill the ventronasal retina; stage 4, expression extends from the ventronasal region to the central region and, less extensively, in dorsal and ventrotemporal directions; stage 5–6, expression is detected in more than three-fourths of the retina (Raymond et al., 1995; Takechi et al., 2003). Dotted line indicates rim of the eye. Arrowhead indicates location of the choroids fissure. (E) A lateral view of an embryonic eye (nasal side to the left and ventral to the bottom) hybridized with the RH2-4 CDR probe at 72 hpf. Hybridized area is indicated with a bracket. (F) A ventral view of a larval eye (nasal side to the left) hybridized with LWS-1 3'-UTR probe at 5.5 dpf. All scale bars, 50 µm.