title: Early duplications of opioid receptor and Peptide genes in vertebrate evolution.
abstract: The opioid receptor family in mammals has four members called delta, kappa, mu, and NOP (the nociceptin/orphanin receptor). We show here that they arose from a common ancestral gene through quadruplication of a large chromosomal region, presumably in the two basal vertebrate tetraploidizations. The four opioid peptide precursor genes have a more complicated evolutionary history involving chromosomal rearrangements but nevertheless seem to have arisen in the same time period as the receptors. Thus the system of opioid peptides and receptors was already established approximately 450 Ma at the dawn of gnathostome evolution.
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden. Dan.Larhammar@neuro.uu.se
authors.forename: Dan
authors.initials: D
authors.lastname: Larhammar
authors.forename: Susanne
authors.initials: S
authors.lastname: Dreborg
authors.forename: Tomas A
authors.initials: TA
authors.lastname: Larsson
authors.forename: Görel
authors.initials: G
authors.lastname: Sundström
mesh_terms: D000818:Animals; D006801:Humans; D010455:Peptides / Q000235:genetics*; D010802:Phylogeny; D011957:Receptors, Opioid / Q000235:genetics*; D013997:Time Factors
chemical_list: D010455:Peptides; D011957:Receptors, Opioid