Fig. 7

Craniofacial defects in def6 and wnt5b MO-injected embryos.

(A–C) 4 dpf, the distance between the eyes is indicated with a double-headed arrow. Def6 and wnt5b MO-injected embryos exhibit a ‘hammerhead’-like phenotype. (D–F) Alcian Blue staining of the cartilage in the head region of 4 dpf embryos. Meckel′s cartilage is indicated with a black arrowhead and does not extend anteriorly beyond the eyes in def6 and wnt5b MO-injected embryos. The ceratohyal is indicated with a red arrowhead and is more posteriorly shifted in the two groups of morphants. Image E; representative image of 105/109 embryos, Image F; representative image of 89/92 embryos. (G) Representative wt embryo and measures taken are shown on the left. Line A was drawn as a baseline for further measurements and also served to normalise distance B. Line B is the distance from line A to the anterior end of the ceratohyal. The ratio of distance B divided by distance A is indicated on the graph. Two- tailed Student′s t-tests indicated a significant (p<0.001; three asterisks) decrease in this ratio in the def6 MO-injected embryos versus wt siblings and between wnt5b MO-injected embryos versus wt siblings. (H) Representative wt embryo and the measures taken are shown on the image on the left. Line A, as before, was used to normalise distance C. Line C is the distance from line A to the anterior end of Meckel′s cartilage. The ratio of this distance is shown on the graph. Injecting 2.5 ng of def6 MO resulted in a significant (p<0.001; three asterisks) decrease in this ratio as determined by two-tailed Student′s t-tests; similarly injection of 5 ng wnt5b MO resulted in a significant (p<0.001; three asterisks) decrease in this ratio.