Fig. 5. The otic placode is significantly reduced in Notch1 mutants. (A,B) Foxi2 expression at 10-11ss (A) and at 12-13ss (B) in whole mounts and sections. Dotted outline/brackets indicate the thickened otic placode region that does not express Foxi2. (A) Corresponding sections showing Foxi2 transcript (blue) and Pax2 protein expression (brown). (C,D) Quantitative comparison of mediolateral placode length in control and Notch1 mutant embryos at 9-11ss (C) and 12-13ss (D; refer to Materials and methods). ^*P<0.05; ^**P<0.005. (E) Quantification of average cell density in control and Notch1 mutants. Placode n values are given in parentheses. Error bars indicate s.e.m. (F) Activated caspase 3 expression (red), indicating a lack of apoptotic cells within the Notch1 mutant otic placode at 10-11ss. Brackets indicate the thickened placode. Scale bar: 50 µm.