title: Phylogenetic analysis of Ciona intestinalis gene superfamilies supports the hypothesis of successive gene expansions.
abstract: Understanding the formation of metazoan multigene families is a good approach to reconstitute the evolution of the chordate genome. In this attempt, the analysis of the genome of selected species provides valuable information. Ciona intestinalis belongs to the urochordates, whose lineage separated from the chordate lineage that later gave birth to vertebrates. We have searched available sequences from the small marine ascidian C. intestinalis for orthologs of members of five vertebrate superfamilies, including tyrosine kinase receptors, ETS, FOX and SOX transcription factors, and WNT secreted regulatory factors, and conducted phylogenetic analyses. We have found that most vertebrate subfamilies have a single C. intestinalis ortholog. Our results support the hypothesis of a gene expansion prior the base of chordate ancestry followed by another gene expansion during vertebrate evolution. They also indicate that Ciona intestinalis genome will be a very valuable tool for evolutionary analyses.
authors.affiliation: Département d'Oncologie Moléculaire, Unité 119 INSERM, IFR57, Marseille, France.
authors.forename: Magalie
authors.initials: M
authors.lastname: Leveugle
authors.forename: Karine
authors.initials: K
authors.lastname: Prat
authors.forename: Cornel
authors.initials: C
authors.lastname: Popovici
authors.forename: Daniel
authors.initials: D
authors.lastname: Birnbaum
authors.forename: François
authors.initials: F
authors.lastname: Coulier
mesh_terms: D000818:Animals; D002938:Ciona intestinalis / Q000235:genetics*; D016000:Cluster Analysis; D030541:Databases, Genetic; D019143:Evolution, Molecular; D051858:Forkhead Transcription Factors; D020440:Gene Duplication; D024282:Genes, sry / Q000235:genetics; D016013:Likelihood Functions; D008957:Models, Genetic; D005810:Multigene Family / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D010802:Phylogeny; D011518:Proto-Oncogene Proteins / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D051153:Wnt Proteins
chemical_list: D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051153:Wnt Proteins; D020794:Receptor Protein-Tyrosine Kinases