Fig. 9. Cryosections of the major inner ear structures of E16.5 Foxi1^+/+ (A,C) and Foxi1^-/- (B,D) mice were labeled using the TUNEL protocol (C,D). (A,B) The ampulla (AM), utricle (UT), endolymphatic duct (ED) and common crus (CC) are enlarged in the mutant. Only one minor difference was detected in the TUNEL staining: a small mesenchymal cell population adjacent to the expanded ED (white arrowheads in D) showed increased labeling. (The same cells are indicated with red arrowheads in B.) (E) The number of TUNEL-positive cells were counted in anatomically corresponding sites in 5 Foxi1^+/+ and 5 Foxi1^-/- inner ears (represented by the the boxed area in C and D). Numbers expressed as means ±s.d. Scale bar: 100 µm.