title: New candidate species most closely related to penguins.
abstract: The phylogenetic position of the order Spenisciformes in Aves remains unclear despite several independent analyses based on morphological and molecular data. To address this issue, we determined the complete mtDNA sequence of rockhopper penguins. The mitochondrial genome, excluding the region from the D-loop to 12SrRNA, was also sequenced for petrel, albatross, frigatebird, loon and grebe, which previous studies suggest are related to penguins. A maximum likelihood analysis of the phylogenetic placement of penguins with 23 birds, including 17 species whose mtDNA sequences were previously reported, suggested that storks are the closest extant relatives of penguins, with 78% and 56% bootstrap supports, depending on the choice of outgroup species. Thus, ciconiiform birds constitute new candidates as the closest extant relatives of penguins (previously proposed candidates were either gaviiform, podicipediform, or procellariiform birds). In addition to this new evidence, our analysis gave evidence to some of ambiguous relationships in the avian tree: our analysis supported a basal split between passerines and other neoavians within Neoaves, and rejected the monophyly of Falconiformes as well as that of loons and grebes.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Masato
authors.initials: M
authors.lastname: Nikaido
authors.forename: Tomi T
authors.initials: TT
authors.lastname: Tsuda
authors.forename: Takanori
authors.initials: T
authors.lastname: Kobayashi
authors.forename: David
authors.initials: D
authors.lastname: Mindell
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
authors.forename: Norihiro
authors.initials: N
authors.lastname: Okada
authors.forename: Masami
authors.initials: M
authors.lastname: Hasegawa
mesh_terms: D000818:Animals; D001483:Base Sequence; D001717:Birds / Q000145:classification* / Q000235:genetics*; D018387:Codon, Initiator; D018388:Codon, Terminator; D004272:DNA, Mitochondrial / Q000235:genetics; D046093:Falconiformes / Q000145:classification / Q000235:genetics; D050259:Genes, Mitochondrial; D016678:Genome; D024101:Mitochondrial Proteins / Q000235:genetics; D010802:Phylogeny; D013045:Species Specificity; D046429:Spheniscidae / Q000145:classification* / Q000235:genetics*
chemical_list: D018387:Codon, Initiator; D018388:Codon, Terminator; D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins