Light-dependent magnetoreception in birds : the crucial step occurs in the dark

  • The Radical Pair Model proposes that the avian magnetic compass is based on spin-chemical processes: since the ratio between the two spin states singlet and triplet of radical pairs depends on their alignment in the magnetic field, it can provide information on magnetic directions. Cryptochromes, blue light-absorbing flavoproteins, with flavin adenine dinucleotide as chromophore, are suggested as molecules forming the radical pairs underlying magnetoreception. When activated by light, cryptochromes undergo a redox cycle, in the course of which radical pairs are generated during photo-reduction as well as during light-independent re-oxidation. This raised the question as to which radical pair is crucial for mediating magnetic directions. Here, we present the results from behavioural experiments with intermittent light and magnetic field pulses that clearly show that magnetoreception is possible in the dark interval, pointing to the radical pair formed during flavin re-oxidation. This differs from the mechanism considered for cryptochrome signalling the presence of light and rules out most current models of an avian magnetic compass based on the radical pair generated during photo-reduction. Using the radical pair formed during re-oxidation may represent a specific adaptation of the avian magnetic compass.

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Author:Roswitha Wiltschko, Margaret Ahmad, Christine Nießner, Dennis Gehring, Wolfgang Wiltschko
URN:urn:nbn:de:hebis:30:3-422071
URL:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4892254
DOI:https://doi.org/10.1098/rsif.2015.1010
ISSN:1742-5662
ISSN:1742-5689
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/27146685
Parent Title (English):Interface
Publisher:The Royal Society
Place of publication:London
Document Type:Article
Language:English
Date of Publication (online):2016/12/01
Date of first Publication:2016/05/04
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2016/12/01
Tag:avian magnetic compass; cryptochrome 1a; flavin redox cycle; light-activation; radical pairs
Volume:13
Issue:118, 20151010
Page Number:7
First Page:1
Last Page:7
Note:
© 2016 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
HeBIS-PPN:428610412
Institutes:Biowissenschaften / Institut für Ökologie, Evolution und Diversität
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 59 Tiere (Zoologie) / 590 Tiere (Zoologie)
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 4.0