wdr68 activity is required for all 1st arch cartilage formation. A), C), E), G) Lateral views of Alcian blue stained animals at 4dpf. B), D), F), H) Ventral views of Alcian blue stained animals at 4dpf. In panels D, F, and H the posterior arches were removed to enhance clarity for observing the anterior arch defects. A), B) Wild type sibling. C), D) Representative 'strong' phenotype dys/dys animal similar to that shown flatmounted in figure 1 panel D with incomplete loss of M and PQ cartilages. The wdr68MO when injected into wild type animals yields a phenotype very similar to that shown here in panels C and D. E), F) Injecting dys/dys animals with antisense wdr68MO causes complete loss of the PQ, M and CH but does not substantially reduce the HM region. G), H) Representative edn1MO knockdown animal lacking the M and CH but retaining the PQ and HM regions.