FIGURE 5.

Cell intercalation and the extracellular matrix do not majorly contribute to jaw joint shaping. Representative ventral stacks of the anterior jaw joint element of a live specimen aged 3.5, 4, 4.5, 5 and 5.5 dpf expressing the transgenic reporters Col2a1aBAC:Mcherry (red) and −4.9sox10:eGFP (green) marking cartilage. Green cells are sox10+ve and col2‐ve and therefore less differentiated than the more mature yellow cells co‐expressing the two transgenes and which form the cartilaginous joint elements. No observation of cell intercalation is made with the cells being clearly identified over time (six cells marked by arrows as examples). The volume occupied by the interstitial space is minor compared to the volume occupied by cells. Scale bar: 20 μm. MC, Meckel's cartilage; PQ, Palatoquadrate