Evidence from nuclear DNA sequences sheds light on the phylogenetic relationships of Pinnipedia: single origin with affinity to Musteloidea

Zoolog Sci. 2006 Feb;23(2):125-46. doi: 10.2108/zsj.23.125.

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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Bayes Theorem
  • Caniformia / classification*
  • Caniformia / genetics*
  • Carnivora / classification
  • Carnivora / genetics
  • Cell Nucleus / genetics
  • DNA / chemistry
  • DNA Primers
  • Evolution, Molecular
  • Likelihood Functions
  • Models, Genetic
  • Molecular Sequence Data
  • Mustelidae / classification*
  • Mustelidae / genetics*
  • Phylogeny*
  • Sequence Analysis, DNA
  • Species Specificity
  • Ursidae / classification
  • Ursidae / genetics

Substances

  • DNA Primers
  • DNA