title: An intron-less betagamma-crystallin-type gene from the sponge Geodia cydonium.
abstract: We report the cloning of a gene encoding a betagamma-crystallin-type protein from a porifera, the Geodia cydonium sponge. The data provide direct, conclusive evidence of the existence of such a gene in the genome of an early diverged metazoan. The cloned gene is found to contain no introns, while proto-splice sites are identified in the nucleotide sequence at positions where introns are located in homologous, very recently diverged vertebrate genes. These findings are discussed in the light of the debate between the introns-late and introns-early theories.
authors.affiliation: Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Antimo
authors.initials: A
authors.lastname: Di Maro
authors.forename: Elio
authors.initials: E
authors.lastname: Pizzo
authors.forename: Maria Vittoria
authors.initials: MV
authors.lastname: Cubellis
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Alessio
mesh_terms: D000818:Animals; D001483:Base Sequence; D003459:Crystallins / Q000235:genetics*; D004247:DNA / Q000737:chemistry / Q000235:genetics; D007438:Introns / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011161:Porifera / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D038204:beta-Crystallins / Q000235:genetics; D038222:gamma-Crystallins / Q000235:genetics
chemical_list: D003459:Crystallins; D038204:beta-Crystallins; C107738:crystallin, gammaB; D038222:gamma-Crystallins; D004247:DNA