title: Dynamic insertion-deletion of introns in deuterostome EF-1alpha genes.
abstract: To test the validity of intron-exon structure as a phylogenetic marker, the intron-exon structure of EF-1alpha genes was investigated for starfish, acornworms, ascidians, larvaceans, and amphioxus and compared with that of vertebrates. Of the 11 distinct intron insertion sites found within the coding regions of the deuterostome EF-1alpha genes, 7 are shared by several taxa, while the remainder are unique to certain taxa. Examination of the shared introns of the deuterostome EF-1alpha gene revealed that independent intron loss or intron insertion must have occurred in separate lineages of the deuterostome taxa. Maximum parsimony analysis of the intron-exon data matrix recovered five parsimonious trees (consistency index = 0.867). From this result, we concluded that the intron-exon structure of deuterostome EF-1alpha has evolved more dynamically than previously thought, rendering it unsuitable as a phylogenetic marker. We also reconstructed an evolutionary history of intron insertion-deletion events on the deuterostome phylogeny, based on several molecular phylogenetic studies. These analyses revealed that the deuterostome EF-1alpha gene has lost individual introns more frequently than all introns simultaneously.
authors.affiliation: Seto Marine Biological Laboratory, Graduate School of Sciences, Kyoto University, 459 Shirahama, Wakayama, 649-2211, Japan. hwada@seto.kyoto-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wada
authors.forename: Mari
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Riki
authors.initials: R
authors.lastname: Sato
authors.forename: Nori
authors.initials: N
authors.lastname: Satoh
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Miyasaka
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Shirayama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002816:Chordata, Nonvertebrate / Q000235:genetics; D002938:Ciona intestinalis / Q000235:genetics; D004447:Echinodermata / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons; D017353:Gene Deletion; D007438:Introns; D007448:Invertebrates / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D020648:Peptide Elongation Factor 1 / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014561:Urochordata / Q000235:genetics; D014714:Vertebrates / Q000145:classification / Q000235:genetics
chemical_list: D020648:Peptide Elongation Factor 1