title: Evidence from nuclear DNA sequences sheds light on the phylogenetic relationships of Pinnipedia: single origin with affinity to Musteloidea.
abstract: 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.
authors.affiliation: Laboratory of Animal Cell Technology, Faculty of Life Science and Technology, Fukuyama University, Japan. jsato@bt.fubt.fukuyama-u.ac.jp
authors.forename: Jun J
authors.initials: JJ
authors.lastname: Sato
authors.forename: Mieczysław
authors.initials: M
authors.lastname: Wolsan
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Hosoda
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Kozue
authors.initials: K
authors.lastname: Hiyama
authors.forename: Mari
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Shinji
authors.initials: S
authors.lastname: Minami
mesh_terms: D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D010872:Caniformia / Q000145:classification* / Q000235:genetics*; D002335:Carnivora / Q000145:classification / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics; D004247:DNA / Q000737:chemistry; D017931:DNA Primers; D019143:Evolution, Molecular; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D045969:Mustelidae / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D001503:Ursidae / Q000145:classification / Q000235:genetics
chemical_list: D017931:DNA Primers; D004247:DNA