title: Functional divergence of former alleles in an ancient asexual invertebrate.
abstract: Theory suggests it should be difficult for asexual organisms to adapt to a changing environment because genetic diversity can only arise from mutations accumulating within direct antecedents and not through sexual exchange. In an asexual microinvertebrate, the bdelloid rotifer, we have observed a mechanism by which such organisms could acquire the diversity needed for adaptation. Gene copies most likely representing former alleles have diverged in function so that the proteins they encode play complementary roles in survival of dry conditions. One protein prevents desiccation-sensitive enzymes from aggregating during drying, whereas its counterpart does not have this activity, but is able to associate with phospholipid bilayers and is potentially involved in maintenance of membrane integrity. The functional divergence of former alleles observed here suggests that adoption of asexual reproduction could itself be an evolutionary mechanism for the generation of diversity.
authors.affiliation: Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK.
authors.forename: Natalia N
authors.initials: NN
authors.lastname: Pouchkina-Stantcheva
authors.forename: Brian M
authors.initials: BM
authors.lastname: McGee
authors.forename: Chiara
authors.initials: C
authors.lastname: Boschetti
authors.forename: Dimitri
authors.initials: D
authors.lastname: Tolleter
authors.forename: Sohini
authors.initials: S
authors.lastname: Chakrabortee
authors.forename: Antoaneta V
authors.initials: AV
authors.lastname: Popova
authors.forename: Filip
authors.initials: F
authors.lastname: Meersman
authors.forename: David
authors.initials: D
authors.lastname: Macherel
authors.forename: Dirk K
authors.initials: DK
authors.lastname: Hincha
authors.forename: Alan
authors.initials: A
authors.lastname: Tunnacliffe
mesh_terms: D000220:Adaptation, Biological; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D002875:Chromosomes / Q000235:genetics; D018076:DNA, Complementary; D003681:Dehydration; D018628:Gene Dosage; D017238:Genes, Helminth; D014644:Genetic Variation; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008051:Lipid Bilayers; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D012100:Reproduction, Asexual; D012403:Rotifera / Q000235:genetics* / Q000502:physiology*
chemical_list: D018076:DNA, Complementary; D015801:Helminth Proteins; D008051:Lipid Bilayers