Expression of hoxb13a (A), six2a (B), tbx3a (C) and pax9 (D) in the caudal fin margin of the tail fin (cfm) and during tail fin regeneration (v, ventral, m, median, d, dorsal compartment). Vertical axis indicates fold change of expression normalized to cfm, v (six2a, tbx3a, pax9) or cfm, m (hoxb13a). Data are represented as mean ± SEM. See also Figure S1.