Figure 4

col10a1a^−/− mutants display a small chondrocranium at 5 dpf and decreased mineralization at 10 dpf compared to wt controls. (A) Ventral view of alcian blue stained WT and col10a1a^−/− larvae at 5 dpf. The distances measured are indicated as described in Mat. and Meth. (B) col10a1a^−/− reveal reduced head size at 5 dpf compared to WT (p < 0.01; WT n = 12, col10a1a^−/− n = 15). Measures are distances from anterior to the posterior end of the ethmoid plate (head length-hl), between the two hyosymplectics (d-hyo), between the articulations joining the Meckel’s cartilage to the palatoquadrate (d-art), and the angle formed by the two ceratohyals (a-cer). (C) Ventral view of alizarin red stained WT and col10a1a^−/− larvae at 10 dpf. The blue arrowheads point to the skeletal elements: maxillary (m), dentary (d), parasphenoid (p), entopterygoid (en), branchiostegal rays 1 and 2 (br1/br2). Inserts show the maxillary and dentary. (D) Fraction (%) of individuals presenting a high (green), reduced (red), or absent (black) level of bone mineralization in the different bone elements in WT and col10a1a^−/− fish at 10 dpf. (WT n = 20, col10a1a^−/− n = 17). (n.s. = non significant) significance: ** p < 0.01, *** p < 0.001, and **** p < 0.0001.