title: Globin genes are present in Ciona intestinalis.
abstract: The key position of the Ciona intestinalis basal to the vertebrate phylogenetic tree brings up the question of which respiratory proteins are used by the tunicate to facilitate oxygen transport and storage. The publication of the Ciona draft genome sequence suggests that globin genes are completely missing and that-like some molluscs and arthropods-the sea squirt uses hemocyanin instead of hemoglobin for respiration. However, we report here the presence and expression of at least four distinct globin gene/protein sequences in Ciona. This finding is in agreement with the ancestral phylogeny of the vertebrate globins. Moreover, it seems likely that the Ciona hemocyanin-like sequences have enzymatic instead of respiratory functions.
authors.affiliation: Institute of Molecular Genetics, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Ebner
authors.forename: Thorsten
authors.initials: T
authors.lastname: Burmester
authors.forename: Thomas
authors.initials: T
authors.lastname: Hankeln
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002938:Ciona intestinalis / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D016678:Genome; D005914:Globins / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid
chemical_list: D005914:Globins