ABSTRACT
Pigmentation patterns in fish are as diverse as any in the animal kingdom. All fish chromatophores, except for the distinctively epithelial melanised cells of the pigmented retinal epithelium, are believed to derive from a transient embryonic tissue called the neural crest. Direct demonstration that pigment cells derive from the neural crest requires lineage labelling studies, in which neural crest cells are cleanly labelled in such a way that their progeny inherit the cellular marker. Understanding the genetic basis for pigment cell development involves analyses of several distinct steps in neural crest development. Pigment patterns change markedly during the life cycles of many organisms including teleosts. A final interesting, yet poorly understood, issue in adult pigment pattern formation concerns roles for neuronal inputs and hormones. A major breakthrough would come from identification of the identity and localisation of pigment cell stem cells and for this the development of a powerful chemical tool to ablate melanophores may well prove helpful.
