CD9 and retinal degeneration: As Fig. 3S indicates, the percentage of cone photoreceptors was significantly decreased in the rd2 retinas at P15, P18 (peak of retinal degeneration), and P24 compared to corresponding wt retinas (wt p15: 4.88 ± 0.68 SEM n = 3, rd2 p15: 3.51 ± 0.06 SEM n = 6 p = 0.0446, wt p18: 4.07 ± 0.22 SEM n = 6, rd2 p18: 2.72 ± 0.28 SEM n = 9 p = 0.0011, wt p24: 4.18 ± 0.08 SEM n = 6, rd2 p24: 2.57 ± 0.05 SEM n = 3 p = 0.0039).