Double-fluorescent whole-mount in situ hybridization of candidates. Ath5 mRNA was detected using TSA-fluorescein (shown in green), and regulator mRNA was visualized using FastRed staining (shown in purple). (a-f) Group 1, repressors in RPCs. (g-k) Group 2, activators in RPCs. (l) A schematic representation of a SWS retina. The box demarcates the magnification shown in the close-ups of the transition zone of Ath5 and candidate regulator expression. (m-o) Group 3, activators in RGCs. (p-r) Group 3, repressors in RGCs. In this and subsequent figures, all images are single horizontal confocal sections of the developing eye at the level of the lens, anterior is to the left. Arrowheads point to sites of co-expression of Ath5 and the candidate regulator.