a-b, Transmitted light photomicrographs of the heads of 48 hpf wild type sibling (a) and tet2-/-, tet3-/- double mutant (b) embryos. c, Quantitation of eye size in 48 hpf wild type sibling and tet2-/-, tet3-/- double mutant embryos. Histograms show mean, error bars represent s.d. in the relative eye size (n =10), two-tailed t-test, *p<0.05. d-g, Assessment of crx (d,f) and gnb3a (e,g), promoter DNA methylation in isolated eyes from 48 hpf wild type sibling (d,e) and tet2-/-, tet3-/- double mutant (f,g) animals. h, Quantitative RT-PCR analysis of the percent relative expression of crx and gnb3a in isolated eyes from 48 hpf wild type sibling (orange columns) and tet2-/-, tet3-/- double mutant (blue columns) animals. Histograms show mean, error bars represent s.e.m of three biological replicates; two-tailed t-test, *p<0.005. Scale bar 100μM in b for a and b.