Delayed neonatal vascularization in P7 Rap1b^−/− retinas. Retinas from P7 littermate Rap1b^−/− (A) and Rap1b^+/− pups (B); littermate Rap1b^+/− (C) and Rap1b^+/+ (D) pups; and P14 littermate Rap1b^−/− (E) and Rap1b^+/− pups (F) were isolated, fixed, mounted, and stained with fluorescent isolectin, as described in “Analysis of retinal neovascularization.” Shown is a representative image of a quarter of each retina. Decrease in vascularization of P7 Rap1b^−/− retinas is absent at the P14 stage. Lines have been inserted to indicate composite images.