Figure 1.

Establishment of the joint initiation timeline. Fins were amputated at the 30% level and permitted to regenerate for 2–5 days before processing for ZNS5 immunofluorescence. Selected timepoints are shown. Fins at 87 hpa frequently exhibited “initiating” joints in the third fin ray from the dorsal or ventral side. The ratios in each image indicate the frequency of initiating joints at each time point. Arrowheads indicate the organizing joint-forming cells and the * in 96 hpa identify the separating rows of joint-forming cells. The scale bar is 20 μm.