Evolution of time-keeping mechanisms: early emergence and adaptation to photoperiod
- 27 July 2011
- journal article
- research article
- Published by The Royal Society in Philosophical Transactions B
- Vol. 366 (1574), 2141-2154
- https://doi.org/10.1098/rstb.2010.0409
Abstract
Virtually all species have developed cellular oscillations and mechanisms that synchronize these cellular oscillations to environmental cycles. Such environmental cycles in biotic (e.g. food availability and predation risk) or abiotic (e.g. temperature and light) factors may occur on a daily, annual or tidal time scale. Internal timing mechanisms may facilitate behavioural or physiological adaptation to such changes in environmental conditions. These timing mechanisms commonly involve an internal molecular oscillator (a ‘clock’) that is synchronized (‘entrained’) to the environmental cycle by receptor mechanisms responding to relevant environmental signals (‘Zeitgeber’, i.e. German for time-giver). To understand the evolution of such timing mechanisms, we have to understand the mechanisms leading to selective advantage. Although major advances have been made in our understanding of the physiological and molecular mechanisms driving internal cycles (proximatequestions), studies identifying mechanisms of natural selection on clock systems (ultimatequestions) are rather limited. Here, we discuss the selective advantage of a circadian system and how its adaptation to day length variation may have a functional role in optimizing seasonal timing. We discuss various cases where selective advantages of circadian timing mechanisms have been shown and cases where temporarily loss of circadian timing may cause selective advantage. We suggest an explanation for why a circadian timing system has emerged in primitive life forms like cyanobacteria and we evaluate a possible molecular mechanism that enabled these bacteria to adapt to seasonal variation in day length. We further discuss how the role of the circadian system in photoperiodic time measurement may explain differential selection pressures on circadian period when species are exposed to changing climatic conditions (e.g. global warming) or when they expand their geographical range to different latitudes or altitudes.Keywords
This publication has 123 references indexed in Scilit:
- Association between mammalian lifespan and circadian free-running period: the circadian resonance hypothesis revisitedBiology Letters, 2010
- A Cyanobacterial Circadian ClockworkCurrent Biology, 2008
- A latitudinal cline in the Chinook salmon ( Oncorhynchus tshawytscha ) Clock gene: evidence for selection on PolyQ length variantsProceedings. Biological sciences, 2008
- Lego clocks: building a clock from partsJournal of Bone and Joint Surgery, 2008
- Structural model of the circadian clock KaiB–KaiC complex and mechanism for modulation of KaiC phosphorylationThe EMBO Journal, 2008
- Dual KaiC-based oscillations constitute the circadian system of cyanobacteriaGenes & Development, 2008
- A sequential program of dual phosphorylation of KaiC as a basis for circadian rhythm in cyanobacteriaThe EMBO Journal, 2007
- Separate oscillating cell groups in mouse suprachiasmatic nucleus couple photoperiodically to the onset and end of daily activityProceedings of the National Academy of Sciences of the United States of America, 2007
- Circadian rhythms in gene transcription imparted by chromosome compaction in the cyanobacterium Synechococcus elongatusProceedings of the National Academy of Sciences of the United States of America, 2006
- Body temperature patterns before, during, and after semi-natural hibernation in the European ground squirrelJournal of Comparative Physiology B, 2002