Fig. 6. kit-dependent and kit-independent regenerative melanophores in D. albolineatus. (A) In wild-type D. albolineatus, many regenerative melanophores (arrowheads) develop by 10 dpa and ultimately form a pattern indistinguishable from that of the unamputated fin. These cells differentiate de novo and have not migrated in from unamputated regions, as revealed by initially rearing fish in the melanin synthesis inhibitor phenylthiourea, allowing new and previously differentiated melanophores to be distinguished from one another (data not shown) (see Rawls and Johnson, 2000). Vertical bars, amputation planes. Arrows, melanophores already present in the unamputated fin. (B) In kit mutant D. albolineatus, regenerative melanophores do not develop by 10 dpa. Dark regions along edges of lepidotrichia are shadows (e.g. black arrow), not melanophores. (C) After longer periods (20 dpa) a few kit-independent regenerative melanophores differentiate (arrowhead), although fins never recover melanophore numbers equivalent to wild-type regenerates. Scale bar: in C, 500 µm for A-C.