title: Selection on length mutations after frameshift can explain the origin and retention of the AP3/DEF-like paralogues in Impatiens.
abstract: Evolution of class B genes through gene duplication has been proposed as an evolutionary mechanism that contributed to the enormous floral diversity. Frameshift mutations are a likely mechanism to explain the divergent C-terminal sequences of MIKC gene subfamilies. So far, the inferences for frameshifts and selective pressures on the C-terminal domain are made for old duplications for which the exact selective pressures are obscured by evolutionary time. This motivated us to study an example of a recent duplication, which allows us to consider in more detail the selective pressures that are involved after duplication. We find that after duplication and frameshift of Impatiens class B genes, the individual codons show no evidence for adaptive selection. It is rather the length of the C-terminal domain that either is strictly conserved or varies strongly. This suggests a role for the length of the C-terminal domain in the retention of duplicated genes.
authors.affiliation: Laboratory of Plant Systematics, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium. steven.janssens@bio.kuleuven.be
authors.forename: Steven B
authors.initials: SB
authors.lastname: Janssens
authors.forename: Tom
authors.initials: T
authors.lastname: Viaene
authors.forename: Suzy
authors.initials: S
authors.lastname: Huysmans
authors.forename: Erik F
authors.initials: EF
authors.lastname: Smets
authors.forename: Koen P
authors.initials: KP
authors.lastname: Geuten
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D016368:Frameshift Mutation; D020440:Gene Duplication; D029069:Impatiens / Q000235:genetics*; D026161:MADS Domain Proteins / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment
chemical_list: D026161:MADS Domain Proteins; D010940:Plant Proteins