title: The phylogenetic status of Paxillosida (Asteroidea) based on complete mitochondrial DNA sequences.
abstract: One of the most important issues in asteroid phylogeny is the phylogenetic status of Paxillosida. This group lacks an anus and suckers on the tube feet in adults and does not develop the brachiolaria stage in early development. Two controversial hypotheses have been proposed for the phylogenetic status of Paxillosida, i.e., Paxillosida is primitive or rather specialized in asteroids. In this study, we determined the complete mitochondrial DNA nucleotide sequences from two paxillosidans (Astropecten polyacanthus and Luidia quinaria) and one forcipulatidan (Asterias amurensis). The mitochondrial genomes of the three asteroids were identical with respect to gene order and transcription direction, and were identical to the previously reported mitochondrial genomes of Asterina pectinifera (Valvatida) and Pisaster ochraceus (Forcipulatida) in this respect. Therefore, the comparison of genome structures was uninformative for the purposes of asteroid phylogeny. However, molecular phylogenetic analyses based on the amino acid sequences and the nucleotide sequences from the five asteroids supported the monophyly of the clade that included the two paxillosidans and Asterina. This suggests that the paxillosidan characters are secondarily derived ones.
authors.affiliation: Seto Marine Biological Laboratory, Kyoto University, 459 Shirahama, Nishimuro-gun, Wakayama 649-2211, Japan. mmatsubara@sci.mbox.media.kyoto-u.ac.jp
authors.forename: Mioko
authors.initials: M
authors.lastname: Matsubara
authors.forename: Miéko
authors.initials: M
authors.lastname: Komatsu
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Araki
authors.forename: Shuichi
authors.initials: S
authors.lastname: Asakawa
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yokobori
authors.forename: Kimitsuna
authors.initials: K
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wada
mesh_terms: D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D018387:Codon, Initiator / Q000235:genetics; D018388:Codon, Terminator / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004447:Echinodermata / Q000145:classification* / Q000235:genetics*; D016678:Genome; D008928:Mitochondria / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D018387:Codon, Initiator; D018388:Codon, Terminator; D004272:DNA, Mitochondrial