Evidence from Nuclear DNA Sequences Sheds Light on the Phylogenetic Relationships of Pinnipedia: Single Origin with Affinity to Musteloidea

• DOI: 10.2108/zsj.23.125
• Publication Date: 2006-04-07T05:58:36Z
• Authors: Jun J. Sato; Mieczyslaw Wolsan; Hitoshi Suzuki; Tetsuji Hosoda; Yasunori Yamaguchi; Kozue Hiyama; Mari Kobayashi; Shinji Minami
• Keywords: Carnivora; Molecular Sequence Data; phylogeny; Evolution, Molecular; 03 medical and health sciences; Species Specificity; Mustelidae; Animals; Arctoidea; 14. Life underwater; Phylogeny; DNA Primers; Cell Nucleus; Likelihood Functions; 0303 health sciences; Base Sequence; Models, Genetic; nuclear DNA; 467; Bayes Theorem; DNA; Sequence Analysis, DNA; Caniformia; Pinnipedia; Ursidae

Considerable long-standing controversy and confusion surround the phylogenetic affinities of pinnipeds, the largely marine group of "fin-footed" members of the placental mammalian order Carnivora. Until most recently, the two major competing hypotheses were that the pinnipeds have a single (monophyletic) origin from a bear-like ancestor, or that they have a dual (diphyletic) origin, with sea lions (Otariidae) derived from a bear-like ancestor, and seals (Phocidae) derived from an otter-, mustelid-, or musteloid-like ancestor. We examined phylogenetic relationships among 29 species of arctoid carnivorans using a concatenated sequence of 3228 bp from three nuclear loci (apolipoprotein B, APOB; interphotoreceptor retinoid-binding protein, IRBP; recombination-activating gene 1, RAG1). The species represented Pinnipedia (Otariidae: Callorhinus, Eumetopias; Phocidae: Phoca), bears (Ursidae: Ursus, Melursus), and Musteloidea (Mustelidae: Mustela, Enhydra, Melogale, Martes, Gulo, Meles; Procyonidae: Procyon; Ailuridae: Ailurus; Mephitidae: Mephitis). Maximum parsimony, maximum likelihood, and Bayesian inference phylogenetic analyses of separate and combined datasets produced trees with largely congruent topologies. The analyses of the combined dataset resulted in well-resolved and well-supported phylogeny reconstructions. Evidence from nuclear DNA evolution presented here contradicts the two major hypotheses of pinniped relationships and strongly suggests a single origin of the pinnipeds from an arctoid ancestor shared with Musteloidea to the exclusion of Ursidae.