Figure 4
Pigment pattern metamorphosis decouples early larval and adult pigment patterns. (a) Close-ups of embryonic/early larval pigment pattern and adult pigment pattern in D. rerio. Images are not to scale (for details, see Parichy and Turner, 2003b). (b, c, d) Schematics illustrating the cellular events of adult pigment pattern formation from the onset of pigment pattern metamorphosis (left panels) to the completion of a juvenile pigment pattern (right panels). (b) In D. rerio, early larval melanophores (large brown cells) are present initially along the horizontal myoseptum (horizontal blue line) and at the margins of the myotomes (the ventral region is illustrated). Subsequently, xanthophores (orange cells) begin to differentiate ventral to the myoseptum and some early larval melanophores are lost (open cells). A few early larval melanophores leave their initial positions to join the developing adult stripes. Metamorphic melanophores (gray cells) differentiate widely scattered over the flank and begin to migrate towards sites of stripe formation (red tracks). These cells become increasingly melanized (small black cells) and additional metamorphic melanophores appear already within the developing adult stripes. (c) In D. nigrofasciatus, early larval melanophores disperse from their initial locations and assume new positions where the adult stripes will form. Some metamorphic melanophores differentiate but these are far fewer than in D. rerio. (d) In D. albolineatus, there are somewhat fewer early larval melanophores along the horizontal myoseptum at the onset of metamorphosis. Many xanthophores differentiate during early metamorphosis and a few melanophores differentiate scattered over the flank. Some of these metamorphic melanophores persist whereas others die (open cells). By late stages of metamorphosis, melanophores and xanthophores are broadly intermingled.
