(A) Schematic drawing of sgRNA target sites (sg 1, sg 2 and sg 3) in the tgfb1 locus. Grey boxes, untranslated region; green boxes, coding region; arrows, sgRNA target sites; bars, intron regions. (B) Delayed tail regeneration in tgfb1 KO tadpoles. The extent of tail regeneration was classified at 72 hpa as normal tail regeneration, weakly delayed tail regeneration, and severely delayed tail regeneration. (C) The phenotypes of tyrosinase KO (control) and tgfb1 KO tadpoles (sg 1 + 2 + 3) at 72 hpa. Black arrowheads show amputation sites. Scale bar, 200 μm.