title: Genetic architecture of metabolic rate: environment specific epistasis between mitochondrial and nuclear genes in an insect.
abstract: The extent to which mitochondrial DNA (mtDNA) variation is involved in adaptive evolutionary change is currently being reevaluated. In particular, emerging evidence suggests that mtDNA genes coevolve with the nuclear genes with which they interact to form the energy producing enzyme complexes in the mitochondria. This suggests that intergenomic epistasis between mitochondrial and nuclear genes may affect whole-organism metabolic phenotypes. Here, we use crossed combinations of mitochondrial and nuclear lineages of the seed beetle Callosobruchus maculatus and assay metabolic rate under two different temperature regimes. Metabolic rate was affected by an interaction between the mitochondrial and nuclear lineages and the temperature regime. Sequence data suggests that mitochondrial genetic variation has a role in determining the outcome of this interaction. Our genetic dissection of metabolic rate reveals a high level of complexity, encompassing genetic interactions over two genomes, and genotype × genotype × environment interactions. The evolutionary implications of these results are twofold. First, because metabolic rate is at the root of life histories, our results provide insights into the complexity of life-history evolution in general, and thermal adaptation in particular. Second, our results suggest a mechanism that could contribute to the maintenance of nonneutral mtDNA polymorphism.
authors.affiliation: Animal Ecology, Department of Ecology and Evolution, University of Uppsala, SE-752 36 Uppsala, Sweden. Goran.Arnqvist@ebc.uu.se
authors.forename: Göran
authors.initials: G
authors.lastname: Arnqvist
authors.forename: Damian K
authors.initials: DK
authors.lastname: Dowling
authors.forename: Paul
authors.initials: P
authors.lastname: Eady
authors.forename: Laurene
authors.initials: L
authors.lastname: Gay
authors.forename: Tom
authors.initials: T
authors.lastname: Tregenza
authors.forename: Midori
authors.initials: M
authors.lastname: Tuda
authors.forename: David J
authors.initials: DJ
authors.lastname: Hosken
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics*; D001517:Coleoptera / Q000235:genetics* / Q000378:metabolism*; D003433:Crosses, Genetic; D004734:Energy Metabolism; D004843:Epistasis, Genetic; D019143:Evolution, Molecular; D005260:Female; D050259:Genes, Mitochondrial; D049750:Genome, Insect; D005838:Genotype; D008297:Male; D011110:Polymorphism, Genetic; D013696:Temperature