Fig. 4. ISH of M/LWS opsin probes to transverse sections of zebrafish eyes. (A,B) Serial eye sections at 1 month pf hybridized with the LWS-1 3'-UTR (A) and LWS-2 3'-UTR (B) probes. Arrows in (A) indicate the sparse hybridization signals of LWS-1. Corresponding locations between the two sections are indicated with a star. (C,D) Serial sections at 2 years pf hybridized with the LWS-1 3'-UTR (C) and LWS-2 3'-UTR (D) probes. The solid and dotted double arrows in (C) indicate the areas where LWS-1 is expressed robustly and sparsely, respectively. The bracket in (D) indicates the area where LWS-2 expression disappeared on the dorsal side of the retina. In all panels, the dorsal side is to the top and ventral is to the bottom. Scale bars, 50 µm (A,B) or 200 µm (C,D).