title: Positive selection on the killer whale mitogenome.
abstract: Mitochondria produce up to 95 per cent of the eukaryotic cell's energy. The coding genes of the mitochondrial DNA may therefore evolve under selection owing to metabolic requirements. The killer whale, Orcinus orca, is polymorphic, has a global distribution and occupies a range of ecological niches. It is therefore a suitable organism for testing this hypothesis. We compared a global dataset of the complete mitochondrial genomes of 139 individuals for amino acid changes that were associated with radical physico-chemical property changes and were influenced by positive selection. Two such selected non-synonymous amino acid changes were found; one in each of two ecotypes that inhabit the Antarctic pack ice. Both substitutions were associated with changes in local polarity, increased steric constraints and α-helical tendencies that could influence overall metabolic performance, suggesting a functional change.
authors.affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Volgade 5-7, 1350 Copenhagen, Denmark. footead@gmail.com
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Foote
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Morin
authors.forename: John W
authors.initials: JW
authors.lastname: Durban
authors.forename: Robert L
authors.initials: RL
authors.lastname: Pitman
authors.forename: Paul
authors.initials: P
authors.lastname: Wade
authors.forename: Eske
authors.initials: E
authors.lastname: Willerslev
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
authors.forename: Rute R
authors.initials: RR
authors.lastname: da Fonseca
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology*; D016678:Genome; D012641:Selection, Genetic; D050685:Whale, Killer / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial
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