Fig. 2

Epistasis analyses reveal an essential role for puma in promoting early- and late-appearing metamorphic melanophore populations. (A) Wild-type adults exhibit a pattern of several horizontal stripes. (B) puma mutant adults exhibit patchy distributions of melanophores and the stripe pattern is not well-formed. (C) kit mutants lack early-appearing metamorphic melanophores and retain late-appearing melanophores that differentiate already in the position of adult stripes. kit mutants also lack most dorsal scale melanophores (Johnson et al 1995 and Parichy et al 1999). (D) puma; kit double mutant lacks virtually all melanophores, indicating a role for puma in the development of residual late-appearing melanophores normally present in the kit mutant. (E) ednrb1 mutants lack the late-appearing metamorphic melanophore population and retain instead early-appearing metamorphic melanophores. (F) puma; ednrb1 double mutant exhibits a more severe melanophore deficit than ednrb1 single mutant, suggesting that puma is essential for the normal development of residual early-appearing melanophores normally present in ednrb1 mutants. (G) fms mutant also lack some late-appearing metamorphic melanophores and retains early-appearing metamorphic melanophores. (H) puma; fms double mutant provides an independent test of whether puma promotes the development of early- appearing metamorphic melanophores. Similar to puma; ednrb1 double mutants, puma; fms double mutants have significantly fewer melanophores than fms single mutants, confirming a role for puma in the development of the early-appearing melanophore population. (I) fms; kit double mutant exhibits a gross reduction in melanophore numbers compared to either single mutant. (J) puma; kit double mutant at three months shows that many melanophores are regained during juvenile and adult development, despite the nearly complete absence of these cells immediately after metamorphosis. Images are of fixed specimens. Scale bars, (A–I) 1 mm, (J) 1 mm.