Transgenic S-opsin expressed in rods produces rod-like photoresponses while inducing S-cone-like spectral sensitivity. A, Family of rhodopsin flash responses from control rho+/− rods. B, Family of S-pigment flash responses from transgenic S-opsinrho−/− rods. Flashes for both figures were delivered at t = 0 s and flash intensity was increased in 0.6 log units. C, Average spectral sensitivities of control rho+/− rods (squares, normalized at 500 nm) and of transgenic S-opsinrho−/− rods (circles, normalized at 360 nm). Error bars indicate SEM. Solid lines represent a third-order polynomial fit to each spectrum.