Placement of DiI at the OV stage. Placement of DiI on the optic vesicle (OV) distal tip leads to labelled cells above the optic disc (OD). (A') The insert shows the DiI placement at the OV distal tip. (A) Drawing of the characteristic labelling pattern in an E7 retina showing lineage traced cells above the OD (n = 3). (B') The insert shows a DiI placement (arrow) on the OV distal tip (outlined with dotted line). (B) A distal tip DiI placement at E17.5 leads to cells located above the OD (n = 7). (C) The region covered by DiI labelled cells is outlined in white on an image of an E7 retina processed for in situ hybridization for visinin. The black box corresponds to an insert showing an image of DiI labelled cells at E7.5. The visinin-free spot (circled) does not overlap with the lineage traced cells above the OD. (D) E17.5 retinal wholemount processed with a rod opsin antibody. Rod outer segments are visible as small white spots (arrows). The coverage of DiI lineage traced cells at E17.5 is outlined in white. The rod free zone (circled) does not overlap with the lineage traced cells above the OD. The black box corresponds to the area of DiI labelled cells shown in D'. Anterior (A), Posterior (P), Proximal (PR), and Distal (D) axes are indicated for the OV. Dorsal (D), Ventral (V), Nasal (N) and Temporal (T) are indicated for the retinal flatmounts. Scale bar in A and B = 1 mm; C = 0.5 mm and D = 50 μm.