Evolution of the tyrosinase gene family in vertebrates. (a) Maximum-likelihood phylogeny of protein sequences from the tyrosinase family based on 570 AA positions. The tree is mid-point rooted. Numbers at the branches denote bootstrap values (maximum likelihood/neighbor joining). Bootstrap values above 50 are shown. Tyrp1a and Tyrp1b are assigned according to the analysis of their genomic environment. (b) Synteny of tyr-containing regions in vertebrate genomes. The human TYR region is syntenic to two tyr paralogons in Tetraodon (Tni), stickleback (Gac) and medaka (Ola). Tyrb was apparently lost in the zebrafish (Dre). (c) Synteny of tyrp1-containing regions in vertebrate genomes. The human TYRP1 region is syntenic to two tyrp1 paralogons in stickleback, medaka and zebrafish. A tyrp1b pseudogene is found in Tetraodon (asterisk). Numbered bars represent genes contributing to conserved synteny, genes that do not contribute to conserved synteny are not shown. Blue bars indicate genes that are duplicated along with tyr or tyrp1b, respectively. Dotted lines connect orthologous genes. Kitb (grey bars), another teleost-specific pigmentation gene duplicate  is found 3' of tyrp1b in the four teleost genomes but belongs to a different paralogon (see text).