title: Heritable variation in heat shock gene expression: a potential mechanism for adaptation to thermal stress in embryos of sea turtles.
abstract: The capacity of species to respond adaptively to warming temperatures will be key to their survival in the Anthropocene. The embryos of egg-laying species such as sea turtles have limited behavioural means for avoiding high nest temperatures, and responses at the physiological level may be critical to coping with predicted global temperature increases. Using the loggerhead sea turtle (Caretta caretta) as a model, we used quantitative PCR to characterise variation in the expression response of heat-shock genes (hsp60, hsp70 and hsp90; molecular chaperones involved in cellular stress response) to an acute non-lethal heat shock. We show significant variation in gene expression at the clutch and population levels for some, but not all hsp genes. Using pedigree information, we estimated heritabilities of the expression response of hsp genes to heat shock and demonstrated both maternal and additive genetic effects. This is the first evidence that the heat-shock response is heritable in sea turtles and operates at the embryonic stage in any reptile. The presence of heritable variation in the expression of key thermotolerance genes is necessary for sea turtles to adapt at a molecular level to warming incubation environments.
authors.affiliation: School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia jamie.tedeschi@graduate.uwa.edu.au.
authors.forename: J N
authors.identifier: http://orcid.org/0000-0002-0662-0484
authors.initials: JN
authors.lastname: Tedeschi
authors.affiliation: School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: W J
authors.initials: WJ
authors.lastname: Kennington
authors.affiliation: School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: J L
authors.initials: JL
authors.lastname: Tomkins
authors.affiliation: Commonwealth Scientific and Industrial Research Organisation, Oceans and Atmosphere Flagship, Floreat, Western Australia 6014, Australia.
authors.forename: O
authors.initials: O
authors.lastname: Berry
authors.affiliation: Marine Science Program, Western Australian Department of Parks and Wildlife, Kensington, Western Australia 6151, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Whiting
authors.affiliation: UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia Australian Institute of Marine Science, Crawley, Western Australia 6009, Australia.
authors.forename: M G
authors.initials: MG
authors.lastname: Meekan
authors.affiliation: School of Animal Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia UWA Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: N J
authors.initials: NJ
authors.lastname: Mitchell
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D057231:Climate Change; D004625:Embryo, Nonmammalian / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D005843:Geography; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018869:Heat-Shock Response; D008954:Models, Biological; D014426:Turtles / Q000196:embryology* / Q000502:physiology
chemical_list: D006360:Heat-Shock Proteins
keywords: adaptation; climate change; embryo; heat shock; heritability; sea turtle