Consistent with the progression of photoreceptor degeneration in retinitis pigmentosa, the RNA-seq data showed that at an early stage of degeneration in the Rds retina (P25), the expression levels of rod-specific genes Crx, Nrl, Rho, Gnat1, Pde6a, Pde6e, and Pde6g had already decreased, while the expression levels for cone-specific genes had not been perturbed. This evidence concerns the gene NRL and retinitis pigmentosa.