Bivalve mollusc circadian clock genes can run at tidal frequency

Marine coastal habitats are complex cyclic environments as a result of sun and moon interactions. In contrast to the well-known circadian orchestration of the terrestrial animal rhythmicity (~24h), the mechanism responsible for the circatidal rhythm (~12.4h) remains largely elusive in marine organis...

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Bibliographic Details
Published in:Proceedings of the Royal Society B: Biological Sciences
Main Authors: TRAN, Damien, PERRIGAULT, Mickael, CIRET, Pierre, PAYTON, Laura
Format: Article in Journal/Newspaper
Language:English
Published: 2020
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Online Access:https://oskar-bordeaux.fr/handle/20.500.12278/189137
https://hdl.handle.net/20.500.12278/189137
https://doi.org/10.1098/rspb.2019.2440
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Summary:Marine coastal habitats are complex cyclic environments as a result of sun and moon interactions. In contrast to the well-known circadian orchestration of the terrestrial animal rhythmicity (~24h), the mechanism responsible for the circatidal rhythm (~12.4h) remains largely elusive in marine organisms. We revealed in subtidal field conditions that the oyster Crassostrea gigas exhibits tidal rhythmicity of circadian clock genes and clock-associated genes. Free-running experiment showed an endogenous circatidal rhythm. In parallel, we showed in the field that oysters’ valve behavior exhibited a strong tidal rhythm combined with a daily rhythm. In the free-running experiment, all behavioral rhythms were circatidal, and half of them were also circadian. Our results fuel the debate on endogenous circatidal mechanisms. In contrast to the current hypothesis on the existence of an independent tidal clock, we suggest that a single “circadian/circatidal” clock in bivalves is sufficient to entrain behavioral patterns at tidal and daily frequencies.