Phylogenetic relationships and orthogenetic evolution of coat color among tamarins (genus Saguinus)

Orthogenetic evolutionary patterns may appear within taxa as a result of developmental constraints on the expression of genetic variation. Metachromism is a theory of variation in mammalian coat color that predicts an orthogenetic evolutionary pattern. This theory was based in part on studies of interspecific and geographic variation in the coat colors of New World monkeys. We tested the theory of metachromism in tamarins (Saguinus) using phylogenetic information derived from mitochondrial DNA sequences. Parsimony analysis of mitochondrial DNA sequences from the D-loop and cytochrome b genes supports recognition of Saguinus as a monophyletic genus composed of two major clades. Coat colors for 16 chromogenetic regions of the tamarin coat were examined using the molecular phylogeny to test predictions of the metachromatic theory. Our results support the hypothesis of an orthogenetic evolutionary pattern for coat color in tamarins.