library_construction_protocol: Both uninjured and injured tail fins were removed caudal to the end of the dorsal vein (at the beginning of the pigment gap). Tissue was collected in chilled PBS and kept on ice for a maximum of one hour before extraction. RNA extraction was performed using the Qiagen RNeasy micro kit and initial quality check and sample concentration determined by NanoDrop. Libraries were prepared by the Genetics Core, Wellcome Trust Clinical Research Facility Edinburgh, using the NEBNext Single Cell/Low Input RNA Library Prep Kit for Illumina according to the provided protocol.