title: An orphaned mammalian beta-globin gene of ancient evolutionary origin.
abstract: Mammals possess multiple, closely linked beta-globin genes that differ in the timing of their expression during development. These genes have been thought to be derived from a single ancestral gene, by duplication events that occurred after the separation of the mammals and birds. We report the isolation and characterization of an atypical beta-like globin gene (omega-globin) in marsupials that appears to be more closely related to avian beta-globin genes than to other mammalian beta-globin genes, including those previously identified in marsupials. Phylogenetic analyses indicate that omega-globin evolved from an ancient gene duplication event that occurred before the divergence of mammals and birds. Furthermore, we show that omega-globin is unlinked to the previously characterized beta-globin gene cluster of marsupials, making this the first report of an orphaned beta-like globin gene expressed in a vertebrate.
authors.affiliation: Laboratory of Molecular Evolution, Department of Molecular Biosciences, Adelaide University, South Australia 5005, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Wheeler
authors.forename: R
authors.initials: R
authors.lastname: Hope
authors.forename: S B
authors.initials: SB
authors.lastname: Cooper
authors.forename: G
authors.initials: G
authors.lastname: Dolman
authors.forename: G C
authors.initials: GC
authors.lastname: Webb
authors.forename: C D
authors.initials: CD
authors.lastname: Bottema
authors.forename: A A
authors.initials: AA
authors.lastname: Gooley
authors.forename: M
authors.initials: M
authors.lastname: Goodman
authors.forename: R A
authors.initials: RA
authors.lastname: Holland
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D020440:Gene Duplication; D005914:Globins / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008322:Mammals / Q000145:classification* / Q000235:genetics*; D008394:Marsupialia / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D005914:Globins