Fig. 2. Fgfr2b and Fgfr1 are expressed in prospective otic placode. Whole mount embryos were probed with labelled cDNA for Fgfr2IIIb (A,C,E,G) and Fgfr1 (I,K) and sectioned in the transverse plane. A section taken through the otic region (the plane is indicated by a line through each embryo) is shown in the panel to the right of each whole embryo. Rostral is to the left. Fgfr2IIIb is expressed in the developing neurectoderm (n) at 3 (A,B), 6 (C,D), 8 (E,F) and 16 (G,H) somites. The onset of Fgfr2IIIb expression in the otic placode (op) coincides with placodal thickening (E,F) and persists to the otic cup (oc) stage (G,H). Fgfr1 is expressed in the developing neurectoderm (n) from at least 4 (I,J) to 7 (K,L) somites. Fgfr1 expression in the otic placode is apparent by 7 somites (K,L).