Fig. 6. Tbx1 is a determinant of otocyst anterior-posterior patterning. (A) 7 µm transverse section through the wild-type anterior otocyst shows a lateral to medial gradient of Lfng signal, decreasing medially. Arrow marks the medial extent of detactable signal. Axes are as shown in I. (B) Section, prepared as in A, through the posterior Tbx1^–/– otocyst. (C-H) Lateral surface views of whole-mount hybridized embryos. Arrowhead in C marks posteroventral Lfng signal. Arrowheads in G and H indicate borders of midbrain Otx1 signal. Arrows indicate the otocyst. (I,J) 40 µm transverse vibratome sections through the anterior otocyst. Arrows indicate common dorsal borders of Pax2 and Gata3 signal; asterisk, low intensity ventromedial Gata3 signal.