title: Gene flow between Drosophila yakuba and Drosophila santomea in subunit V of cytochrome c oxidase: A potential case of cytonuclear cointrogression.
abstract: Introgression is the effective exchange of genetic information between species through natural hybridization. Previous genetic analyses of the Drosophila yakuba-D. santomea hybrid zone showed that the mitochondrial genome of D. yakuba had introgressed into D. santomea and completely replaced its native form. Since mitochondrial proteins work intimately with nuclear-encoded proteins in the oxidative phosphorylation (OXPHOS) pathway, we hypothesized that some nuclear genes in OXPHOS cointrogressed along with the mitochondrial genome. We analyzed nucleotide variation in the 12 nuclear genes that form cytochrome c oxidase (COX) in 33 Drosophila lines. COX is an OXPHOS enzyme composed of both nuclear- and mitochondrial-encoded proteins and shows evidence of cytonuclear coadaptation in some species. Using maximum-likelihood methods, we detected significant gene flow from D. yakuba to D. santomea for the entire COX complex. Interestingly, the signal of introgression is concentrated in the three nuclear genes composing subunit V, which shows population migration rates significantly greater than the background level of introgression in these species. The detection of introgression in three proteins that work together, interact directly with the mitochondrial-encoded core, and are critical for early COX assembly suggests this could be a case of cytonuclear cointrogression.
authors.affiliation: Interdisciplinary Graduate Program in Genetics, The University of Iowa, Iowa City, Iowa, 52242.
authors.forename: Emily A
authors.initials: EA
authors.lastname: Beck
authors.affiliation: The Department of Biology, The University of Iowa, Iowa City, IA, 52242.
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Thompson
authors.affiliation: The Department of Biology, The University of Iowa, Iowa City, IA, 52242.
authors.forename: Joel
authors.initials: J
authors.lastname: Sharbrough
authors.affiliation: The Department of Biology, The University of Iowa, Iowa City, IA, 52242.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Brud
authors.affiliation: Interdisciplinary Graduate Program in Genetics, The University of Iowa, Iowa City, Iowa, 52242. ana-llopart@uiowa.edu.|The Department of Biology, The University of Iowa, Iowa City, IA, 52242. ana-llopart@uiowa.edu.
authors.forename: Ana
authors.initials: A
authors.lastname: Llopart
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics*; D004330:Drosophila / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics*; D051456:Gene Flow; D006824:Hybridization, Genetic; D016013:Likelihood Functions; D008297:Male; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D003576:Electron Transport Complex IV
keywords: Coevolution; coadaptation; cytochrome c oxidase; gene flow; introgression