Fig. 7. Gcm2 and Foxn1 expression was not detectable in Eya1^–/– embryos. (A,B) Coronal sections through the 3rd pharyngeal pouch of E10.5 wild-type and Eya1^–/– embryos showing that Gcm2 is strongly expressed in the 3rd pouch endoderm in wild-type embryos (arrow, A) and its expression was not detectable in Eya1^–/– embryos (arrow, B). (C,D) Sagittal sections through the 3rd pharyngeal region showing that Foxn1 is expressed in the ventral region of the thymus/parathyroid primordia at E11.5 of wild-type embryos (arrow, C), but its expression was not detectable in Eya1^–/– embryos (arrow, D). Note that the 3rd pouch is attached to the pharyngeal endoderm and does not separate as buds to form the primordia of thymus/parathyroid in Eya1^–/– embryos. Cranial is up (A-D) and dorsal is to the left (C,D). a, pharyngeal arches; baa3, 3rd branchial arch arteries; ph, pharynx.