The evolution of morphological complexity in zebrafish stripes.

The zebrafish pigment stripe pattern is a complex tissue containing iridophores, xanthophores and multiple melanocyte types. Mutational analysis reveals that both ancient and recent gene duplications are involved in the generation or maintenance of the pattern complexity. Receptor tyrosine kinases kit and fms, products of an ancient gene duplication, are required in distinct types of melanocytes and xanthophores. Transcription factors mitfa and mitfb, results of a teleost-specific duplication, partition gene expression and function between different sets of melanocytes. Understanding the roles of these duplicated genes in zebrafish allows us to predict roles for their precursors in ancestral vertebrates.