In situ hybridization for the Hh target genes Gli1 (A(*), B(*)) and Ptc1 (C(*), D(*)) reveals reduced expression for both genes in orJ retinas at P0. (E(*), F(*)) Ptc2 mRNA expression is undetectable in either genotype. (G(*), H(*)) Hhip transcript is expressed in wild type retinas, but absent in orJ retinas. (I(*), J(*)) In situ hybridization for Vsx2 mRNA serves as a control. Scale bars: 250 µm (A–J); 40 µm (A*–J*). NBL, neuroblast layer; DCL, differentiated cell layer.