Fig. 1.

Cartoon of wild-type patterns on the body of zebrafish. a Patterns form sequentially outward from the central interstripe, labeled X0, with additional dorsal stripes and interstripes labeled 1D, X1D, 2D, X2D from the center (horizontal myoseptum) dorsally outward (similarly, ventral stripes and interstripes are labeled 1V, X1V, 2V, etc); see Supplementary Fig. 2 for zebrafish anatomy. Iridophores spread outward from the center (at the horizontal myoseptum), transitioning into loose to mark stripes and aggregating in dense form to produce new interstripes^2,9. Xanthophores, initially spread across the body in loose or larval form, respond to dense iridophores by adopting a dense form themselves^10,15,31. Melanophore birth relies on long-range cues from xanthophores and iridophores^10,19. Timeline is redrawn from schematic by Singh & Nüsslein-Volhard² with different symbols used. b Cells are arranged in one-cell thick layers, with xanthophores at the surface, iridophores in the middle, and melanophores (present only in stripes) in the deepest layer (a fourth layer of so-called L-iridophores forms after patterns have developed)^6,13–15