Although genes showing type I derepression demonstrated staining in the majority of cells in the ONL, two lines of evidence suggest that these genes are not completely derepressed in these cells when compared to their expression in S-opsin–expressing cones. First, close evaluation of the staining pattern of a number of type I genes in the rd7 mutant retina (e.g., see Table S1, genes G9, G19, and G24), reveals that, in addition to the background staining throughout the ONL, there is a more darkly staining subpopulation of cells scattered throughout this layer in a distribution corresponding to that of the supernumerary S-cone opsin-expressing cells. This pattern of staining suggests that these genes are more highly expressed in S-opsin expressing cells than in the hybrid cells of the rd7 retina.