Fig. 3. Double in situ hybridization defining the domains of iro1 and iro7 expression. Expression patterns of iro1 (A-D,I-L) and iro7 (E-H,M-P). (A-H) Double in situ hybridization with otx2 (A,E), with pax2.1 (B,F), with gbx1 (C,G), and with hoxb1b (D,H) at 80% epiboly. (I,M) At the tailbud stage, iro1 and iro7 are expressed in partially overlapping patterns with ngn1. (J,N) neural crest cells marked by fkd6 expression are within a domain where iro1 and iro7 are expressed. (K,O) By early somitogenesis, expression of iro1 and iro7 is excluded from the MHB region marked by pax2.1. (L,P) iro1 and iro7 are expressed in different locations in the hindbrain: iro1 is expressed in rhombomere 1 and caudally from rhombomere 5, while iro7 is expressed in rhombomeres 3 and 4. (A-P) Anterior towards the top, dorsal view.