title: Inversions and adaptation to the plant toxin ouabain shape DNA sequence variation within and between chromosomal inversions of Drosophila subobscura.
abstract: Adaptation is defined as an evolutionary process allowing organisms to succeed in certain habitats or conditions. Chromosomal inversions have the potential to be key in the adaptation processes, since they can contribute to the maintenance of favoured combinations of adaptive alleles through reduced recombination between individuals carrying different inversions. We have analysed six genes (Pif1A, Abi, Sqd, Yrt, Atpα and Fmr1), located inside and outside three inversions of the O chromosome in European populations of Drosophila subobscura. Genetic differentiation was significant between inversions despite extensive recombination inside inverted regions, irrespective of gene distance to the inversion breakpoints. Surprisingly, the highest level of genetic differentiation between arrangements was found for the Atpα gene, which is located outside the O1 and O7 inversions. Two derived unrelated arrangements (O3+4+1 and O3+4+7) are nearly fixed for several amino acid substitutions at the Atpα gene that have been described to confer resistance in other species to the cardenolide ouabain, a plant toxin capable of blocking ATPases. Similarities in the Atpα variants, conferring ouabain resistance in both arrangements, may be the result of convergent substitution and be favoured in response to selective pressures presumably related to the presence of plants containing ouabain in the geographic locations where both inversions are present.
authors.affiliation: Departament de Genètica and IRBio, Facultat de Biologia, Universitat de Barcelona, Barcelona 08028, Spain.|Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain.|Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Cinta
authors.initials: C
authors.lastname: Pegueroles
authors.affiliation: Department of Neurochemistry and Neuropharmacology, IIBB-CSIC, Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Ferrés-Coy
authors.affiliation: Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences, Universitat Pompeu Fabra, IMIM (Hospital del Mar Medical Research Institute), Dr. Aiguader, 88, 08003 Barcelona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Martí-Solano
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Aquadro
authors.affiliation: Departament de Genètica and IRBio, Facultat de Biologia, Universitat de Barcelona, Barcelona 08028, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Pascual
authors.affiliation: Departament de Genètica and IRBio, Facultat de Biologia, Universitat de Barcelona, Barcelona 08028, Spain.
authors.forename: Francesc
authors.initials: F
authors.lastname: Mestres
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D007446:Chromosome Inversion / Q000187:drug effects; D059006:Chromosomes, Insect / Q000737:chemistry / Q000187:drug effects*; D004330:Drosophila / Q000187:drug effects* / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D010042:Ouabain / Q000378:metabolism / Q000633:toxicity*; D010944:Plants / Q000737:chemistry / Q000378:metabolism; D011110:Polymorphism, Genetic; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism; D014118:Toxins, Biological / Q000096:biosynthesis / Q000378:metabolism / Q000633:toxicity*
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; D051860:Fragile X Messenger Ribonucleoprotein 1; D010042:Ouabain; D016601:RNA-Binding Proteins; D000254:Sodium-Potassium-Exchanging ATPase; D014118:Toxins, Biological; C121808:Abi protein, Drosophila; C467328:FMR1 protein, Drosophila; C081480:sqd protein, Drosophila; C472021:ATPalpha protein, Drosophila