Figure 1.

Reduction in cartilage in foxl1 mutants. (A) Alcian blue (staining cartilage) of WT and foxl1^-/- (6 dpf n = 24, 10 dpf n = 20) embryos, indicating a delay in ceratohyal cartilages at 6 dpf (green arrowhead), but a recovery begins by 10 dpf. Alizarin red indicates a delay in the ossification of the hyomandibula (red arrowhead and inserts) in foxl1 mutants at 6 dpf, which also begins to normalize by 10 dpf. (B) Longitudinal sections through jaw, demonstrating a reduced presence of cartilage formation in the upper and lower jaw as indicated by the red arrows at 6 dpf, along with a shortened and round jaw structure that progresses by 10 dpf (red circle). PQ, palatoquadrate; M, Meckel; HY, hyomandibula (hyosympletic); CH, ceratohyal; CB, ceratobranchials (yellow arrowhead); OP, operculum. Zoomed-in inserts in each panel focus on the cartilage and primary centres of ossification of the hyomandibula. Scale bars are 200 µm.