Fig. 3. Agenesis of GT in Shh^-/- mice. (A,B) 12.5 dpc Shh^-/- embryos show severe defects in the initiation of GT outgrowth (A, wild type; B, Shh^-/- mice). Sagittal sections (as illustrated in a) were obtained and stained with Hematoxylin and Eosin. (D,F) Drastic reduction of Fgf8 expression in the GT of Shh^-/- mice compared with wild type (C,E). Note that Fgf8 expression was detected in the limb buds, but was very reduced in the GT, of Shh^-/- mice (D). Scale bars: 62.5 µm in A,B; 250 µm in C-F.