transparent mutants show a reduction in iridophore pigmentation. (A,C,D) Wild type and (B,E-H) tra mutants. At 5 dpf, mutant larvae show strong reduction in iridophores in dorsal and ventral positions (B) as compared to wild type (A). Arrows in panels A and B highlight the appearance and position of iridophores in larvae. No other defects are apparent. Two months old wild type animals (C) present a fully developed pigment pattern, while tra individuals (E) developed only few iridophores, visible between the dark stripes. (G) Close-up of the region boxed in panel E. At that age, melanophores are reduced in number in the mutants, however, the typical four stripes developed. While the mutant fish grow, the melanophore stripes break up into spots (F, close up in H), compare six months old tra mutant (F) to wild type (D) of the same age. The abdominal cavity, typically covered by a thick sheet of iridophores in wild type, lacks this cell type in tra mutants. Iridophores of the eyes are strongly reduced throughout life in the mutants. Pigment patterning of fins and scales appear normal. Scale bars: 0.5 mm (A,B); 1 mm (C,E), 3 mm (D,F).