Fig. 2. Homeotic pharyngeal arch phenotype of moz mutant larvae. Pharyngeal cartilage phenotypes in wholemounts (A-C) and flat mounts (D-I) of wild-type (A,D,G), moz mutant (B,E,H) and moz-MO-injected (C,F,I) larvae at 4 days. (A-F) In moz mutants (E) and moz-MO-injected animals (F), both second arch cartilages (M', pq') adopt shapes resembling the first arch jaw cartilages. The HM region of HS is deleted (arrow in B). The transformation is incomplete in that the pterygoid process is not seen duplicated in moz mutants or moz-MO injected animals. An ectopic dorsal cartilage (arrowhead) is seen in the moz mutant third arch. (G-I) Third pharyngeal arch cartilages, with medial to the left. moz mutants (H) and moz-MO injected animals (I) display a homeotic third arch phenotype, with a process on their lateral end resembling the retroarticular process on Meckel's cartilage. am, adductor mandibulae; ch, ceratohyal; hm, hyomandibular; hs, hyosymplectic; m, Meckel's; pq, palatoquadrate; ptp, pterygoid process; sy, symplectic. Scale bars: 50 µm.