Figure 4  Morphology of wild-type and Ptdsr -/- retinas. Serial sagittal sections of (a-d) wild-type and (e-h) Ptdsr -/- retina were analyzed for developmental abnormalities at (a,e) E12.5, (b,f) E16.5, (c,g) E18.5, and (d,h) P0. Normal patterning of the retina was observed in Ptdsr -/-embryos, with an outer granular layer (OGL), outer plexiform layer (OPL), inner granular layer (IGL) and inner plexiform layer (IPL). Note that the IGL in Ptdsr -/- retinas is less thick than that in wild-type littermates in comparing (c,g) and (d,h). Morphometric analysis (numbered lines) of wild-type and Ptdsr -/- retinas confirmed the initial finding of a thinner retina in Ptdsr -/- animals than in wild-type (all values in μm). Scale bar, 50 μm.