Quantitative analyses of melanophore accumulation in wild-type D. rerio and D. albolineatus and their respective kit mutants. In D. rerio (upper plot) wild-type melanophore densities (means±1 s.e.) are relatively constant during the first half of pigment pattern metamorphosis (∼15-36 dpf) but then increase dramatically during the second half of pigment pattern metamorphosis (∼37-49 dpf), corresponding to the appearance of new melanophores within stripes. Note that total melanophore numbers (as opposed to densities) increase throughout metamorphosis. In kit mutants there are no melanophores until late metamorphosis when residual LM melanophores develop. In D. albolineatus (lower plot), wild-type melanophore densities increase more slowly through metamorphosis and never reach the same maximum as in wild-type D. rerio. kit mutant D. albolineatus completely lack melanophores during early pigment pattern metamorphosis, then recover a few residual LM melanophores during late pigment pattern metamorphosis. Vertical bars to the right of plots indicate the inferred final contributions of EM and LM melanophores to the different pigment patterns. The timing of pigment pattern metamorphosis was somewhat delayed in these analyses compared with previous studies, presumably owing to slight differences in rearing conditions.
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