Retinal hypoplasia in dmbx1 morphants at 72 hpf. Coronal plastic sections (~ 1 μm) of retina from un-injected (A), MO-injected (B, D, F), and mMO-injected (C, E, G) embryos. Layers in the retina can be clearly distinguishable at this stage: retinal ganglion cell layer (RGC), inner nuclear layer (INL), and photoreceptor layer (PR). Measurements of the retinal cross-sectional area summarized in the graph (H). Asterisk indicates significant difference (p < 0.05) between the morphant samples and the controls. MO, morpholino; mMO, mismatch morpholino.