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dc.contributor.authorAppenroth, Daniel
dc.contributor.authorMelum, Vebjørn Jacobsen
dc.contributor.authorWest, Alexander Christopher
dc.contributor.authorDardente, Hugues
dc.contributor.authorHazlerigg, David
dc.contributor.authorWagner, Gabriela
dc.date.accessioned2020-12-08T13:35:39Z
dc.date.available2020-12-08T13:35:39Z
dc.date.issued2020-08-21
dc.description.abstractOrganisms use changes in photoperiod to anticipate and exploit favourable conditions in a seasonal environment. While species living at temperate latitudes receive day length information as a year-round input, species living in the Arctic may spend as much as two-thirds of the year without experiencing dawn or dusk. This suggests that specialised mechanisms may be required to maintain seasonal synchrony in polar regions. Svalbard ptarmigan (<i>Lagopus muta hyperborea</i>) are resident at 74–81°N latitude. They spend winter in constant darkness (DD) and summer in constant light (LL); extreme photoperiodic conditions under which they do not display overt circadian rhythms. Here, we explored how Arctic adaptation in circadian biology affects photoperiodic time measurement in captive Svalbard ptarmigan. For this purpose, DD-adapted birds, showing no circadian behaviour, either remained in prolonged DD, were transferred into a simulated natural photoperiod (SNP) or were transferred directly into LL. Birds transferred from DD to LL exhibited a strong photoperiodic response in terms of activation of the hypothalamic thyrotropin-mediated photoperiodic response pathway. This was assayed through expression of the <i>Eya3</i>, <i>Tshβ</i> and deiodinase genes, as well as gonadal development. While transfer to SNP established synchronous diurnal activity patterns, activity in birds transferred from DD to LL showed no evidence of circadian rhythmicity. These data show that the Svalbard ptarmigan does not require circadian entrainment to develop a photoperiodic response involving conserved molecular elements found in temperate species. Further studies are required to define how exactly Arctic adaptation modifies seasonal timer mechanisms.en_US
dc.identifier.citationAppenroth D, Melum VJ, West AC, Dardente H, Hazlerigg D, Wagner G. Photoperiodic induction without light-mediated circadian entrainment in a High Arctic resident bird. Journal of Experimental Biology. 2020;223(16)en_US
dc.identifier.cristinIDFRIDAID 1856860
dc.identifier.doihttps://doi.org/10.1242/jeb.220699
dc.identifier.issn0022-0949
dc.identifier.issn1477-9145
dc.identifier.urihttps://hdl.handle.net/10037/20028
dc.language.isoengen_US
dc.publisherThe Company of Biologistsen_US
dc.relation.ispartofAppenroth, D. (2021). Circadian-based processes in the High Arctic: activity, thermoregulation and photoperiodism in the Svalbard ptarmigan (<i>Lagopus muta hyperborea</i>). (Doctoral thesis). <a href=https://hdl.handle.net/10037/20675 >https://hdl.handle.net/10037/20675 </a>.
dc.relation.journalJournal of Experimental Biology
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2020 The Author(s)en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480en_US
dc.titlePhotoperiodic induction without light-mediated circadian entrainment in a High Arctic resident birden_US
dc.type.versionsubmittedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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