Movie 1.

Production of nuclear debris following ablation healing. Two views of a tailbud imaged immediately after ablation on a two-photon microscope using H2B-GFP transgenic line to mark nuclei. The first panel is a maximum projection of several lateral slices of the tailbud to visualise the pre-somitic mesoderm. The second panel is a maximum projection of several medial slices of the tailbud to visualise the dorsal progenitors. The ablation location can be observed by the decreased fluorescence intensity in dorsal region of the tailbud in the second panel. Nuclear debris is first observed after 1 hour and becomes prevalent around 90 minutes in the dorsal medial region of the tailbud. The debris moves rapidly and is then observed at high amounts in the lateral PSM by 100 minutes.