Fig. 1. Expression of ephrin A5 and ephrin A2 in the developing chick retina. Whole-mount and section in situ hybridization of HH stage 12 (A), HH stage 18 (B), E4 (D) and E8 (C,E) chick embryos with digoxigenin-labeled riboprobes. Samples were hybridized with antisense probes for ephrin A5 (AC) or ephrin A2 (D,E). (C, parts b,c; E, parts b,c) are enlargements of the nasal and temporal areas boxed in the left panels (C, part a; E part a), respectively. In section in situ hybridization, nasal (N, anterior) is upwards, and temporal (T, posterior) is downwards. Scale bars: 100 µm in B, part b; 600 µm in C, part a and E, part a; 200 µm in D.