title: Seasonal gene expression in a migratory songbird.
abstract: The annual migration of a bird can involve thousands of kilometres of nonstop flight, requiring accurately timed seasonal changes in physiology and behaviour. Understanding the molecular mechanisms controlling this endogenous programme can provide functional and evolutionary insights into the circannual biological clock and the potential of migratory species to adapt to changing environments. Under naturally timed photoperiod conditions, we maintained captive Swainson's thrushes (Catharus ustulatus) and performed RNA sequencing (RNA-Seq) of the ventral hypothalamus and optic chiasma to evaluate transcriptome-wide gene expression changes of individuals in migratory condition. We found that 188 genes were differentially expressed in relation to migratory state, 86% of which have not been previously linked to avian migration. Focal hub genes were identified that are candidate variables responsible for the occurrence of migration (e.g. CRABP1). Numerous genes involved in cell adhesion, proliferation and motility were differentially expressed (including RHOJ, PAK1 and TLN1), suggesting that migration-related changes are regulated by seasonal neural plasticity.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 610 Charles E Young Dr. South, Rm. 4162, Los Angeles, CA, 90095, USA.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Johnston
authors.affiliation: Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.|Department of Biology, University of Hawaii Hilo, Hilo, HI, 96720, USA.
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Paxton
authors.affiliation: Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
authors.forename: Frank R
authors.initials: FR
authors.lastname: Moore
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 610 Charles E Young Dr. South, Rm. 4162, Los Angeles, CA, 90095, USA.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Wayne
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 610 Charles E Young Dr. South, Rm. 4162, Los Angeles, CA, 90095, USA.|Center for Tropical Research, Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Smith
mesh_terms: D025041:Animal Migration; D000818:Animals; D015870:Gene Expression; D017440:Photoperiod; D012621:Seasons; D020308:Songbirds / Q000235:genetics*; D059467:Transcriptome
keywords: 
  Catharus ustulatus
  ; Swainson's thrush; circadian rhythm; circannual rhythm; migratory bird; photoperiod