Molecular phylogenetic study on the origin and evolution of Mustelidae

The family Mustelidae, which consists of Mustelinae, Lutrinae, Melinae, and Taxidiinae, is the largest family among Carnivora and is a highly diverse group. Recent molecular phylogenetic studies have clarified the phylogenetic relations among Mustelidae, but there remain several unresolved problems, particularly concerning the deep branchings. Whereas many studies support the monophyly of Mustelidae + Procyonidae among Musteloidea, the relations between Mustelidae + Procyonidae, Ailuridae, and Miphitidae are still unclear. To address these problems, we inferred a tree on the basis of the sequences of mitochondrial genomes and of multiple nuclear genes using the maximum likelihood method. Our results strongly support the hypothesis that the Taxidiinae branched at first, followed by the branching of the Melinae. After that, Mustelinae diversified, and Lutrinae evolved within Mustelinae. With respect to the deep branchings in Musteloidea, the Ailuridae/Mephitidae monophyly tree and the Mephitidae-basal tree are indistinguishable in log-likelihood score, and this problem remains unresolved.