Final Report Summary - REGENERATEACROSS (A Cross Species Approach to Understand the Mechanism and Evolution of Limb Regeneration Capacity) This project uncovered how fibroblast cells rebuild the skeleton during axolotl limb regeneration. We have traced the same cells during injury responses in non-regenerative frogs and mice and found that the cells can migrate and accumulate at injury sites. In addition, this project has established the methods to understand why mouse and frog fibroblasts do not mount a regeneration response. This will allow us in future to identify factors that are blocking mouse fibroblasts from regenerating limbs. Our project identified several important signalling factors that induce regeneration in the axolotl and that will be tested on mammalian cells.