Fig. 2. Fate mapping the canal pouch. (A) Otic epithelia were labeled with DiI at the positions shown. Examples are shown at the time of injection on E4 (B,E,H) and again at E7 (C,D,F,G,I,J,L,M). Partially dissected E7 ears were imaged under fluorescence (C,F,I,L), combined fluorescence and bright field microscopy (D,G,J) or as a paint-fill for orientation (M). (K) Summary of fate mapping data. The number of specimens with DiI-labeled cells in the canals and common crus at E7 are shown in red and green, respectively. The common crus (long arrows), anterior canal (double arrows) and anterior ampulla (short arrows) are indicated. A region between the anterior ampulla and canal (flanked by arrowheads) is consistently unlabeled. See text for further details. Orientations in B applies to A, E and H. Orientations in D applies to C,F,G,I,J and L. M, medial; L, lateral; AA, anterior ampulla. Scale bars: in A, 200 µm; in B, 200 µm for E,H; in D, 200 µm for C,F,G,I,J,L.