We investigated the methylation statusof photoreceptor (PR) specific genes in the developing mouse retina. We hypothesize that the regional hypomethylation of Rho andOpn1sw is characteristic of photoreceptor (PR) precursor cells and once cellfate is determined. these early methylation patterns becomecompletely unmethylated in expressing PRs but persist in thenon-expressing PRs. Additionally, the regional hypomethylationnear the TSS of Rbp3 and Rho that did not correlate with expressionat time points as early as E11.5 likely represent differentialmethylation that leads to lineage determination by regulatinggene expression in the developing retina.