title: Migration phenology and breeding success are predicted by methylation of a photoperiodic gene in the barn swallow.
abstract: Individuals often considerably differ in the timing of their life-cycle events, with major consequences for individual fitness, and, ultimately, for population dynamics. Phenological variation can arise from genetic effects but also from epigenetic modifications in DNA expression and translation. Here, we tested if CpG methylation at the poly-Q and 5'-UTR loci of the photoperiodic Clock gene predicted migration and breeding phenology of long-distance migratory barn swallows (Hirundo rustica) that were tracked year-round using light-level geolocators. Increasing methylation at Clock poly-Q was associated with earlier spring departure from the African wintering area, arrival date at the European breeding site, and breeding date. Higher methylation levels also predicted increased breeding success. Thus, we showed for the first time in any species that CpG methylation at a candidate gene may affect phenology and breeding performance. Methylation at Clock may be a candidate mechanism mediating phenological responses of migratory birds to ongoing climate change.
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Saino
authors.affiliation: Department of Earth and Environmental Sciences (DISAT), University of Milano Bicocca, Piazza della Scienza, 1, I-20126 Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Ambrosini
authors.affiliation: EPIGET - Epidemiology, Epigenetics and Toxicology Lab - Department of Clinical Sciences and Community Health, University of Milan, via San Barnaba 8, I-20122 Milan, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Albetti
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Caprioli
authors.affiliation: EPIGET - Epidemiology, Epigenetics and Toxicology Lab - Department of Clinical Sciences and Community Health, University of Milan, via San Barnaba 8, I-20122 Milan, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: De Giorgio
authors.affiliation: Department of Earth and Environmental Sciences (DISAT), University of Milano Bicocca, Piazza della Scienza, 1, I-20126 Milan, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Gatti
authors.affiliation: Swiss Ornithological Insititute, Seerose 1, CH-6204, Sempach, Switzerland.
authors.forename: Felix
authors.initials: F
authors.lastname: Liechti
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Parolini
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Romano
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Romano
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Scandolara
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Gianfranceschi
authors.affiliation: EPIGET - Epidemiology, Epigenetics and Toxicology Lab - Department of Clinical Sciences and Community Health, University of Milan, via San Barnaba 8, I-20122 Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Bollati
authors.affiliation: Department of Biosciences, University of Milan, via Celoria 26, I-20133 Milan, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Rubolini
mesh_terms: D025041:Animal Migration; D000818:Animals; D056926:CLOCK Proteins / Q000235:genetics*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D010641:Phenotype; D012726:Sexual Behavior, Animal; D046388:Swallows / Q000235:genetics* / Q000502:physiology*
chemical_list: D056926:CLOCK Proteins