In zebrafish and many other teleosts the larval-to-adult transformation involves changes in a variety of traits including the pigment pattern. Commonly referred to as a "metamorphosis" by larval fish biologists, these changes occur between about 2 and 4 weeks in zebrafish.

Metamorphosis entails dramatic changes in the pigment pattern. The early larva has stripes of black melanophores (the fish equivalent of melanocytes). The adult has different stripes of melanophores, with yellow xanthophores in between and iridescent iridophores throughout the flank. There is no clear correspondence between larval and adult stripes. So how is the early larval pigment pattern transformed into that of the adult?

Pattern metamorphosis could result from rearrangements of early larval melanophores. Or, different populations of melanophores could contribute to patterns during different stages of the life cycle. Our studies demonstrate that in zebrafish and several other danios, most adult melanophores differentiate from latent precursors with relatively little contribution from early larval melanophores. Some of these cells arise already at sites of adult stripe formation and others migrate short distances to join the developing stripes. These changes can be seen best in movies. An array of pigment pattern mutants allow for the dissection of pattern-forming mechanisms in zebrafish, and can suggest testable hypotheses for pigment pattern diversification among species.