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Weather and Seasons Together Demand Complex Biological Clocks

Troein, Carl LU orcid ; Locke, James C.W. ; Turner, Matthew S. and Millar, Andrew J. (2009) In Current Biology 19(22). p.1961-1964
Abstract

The 24-hour rhythms of the circadian clock [1] allow an organism to anticipate daily environmental cycles, giving it a competitive advantage [2, 3]. Although clock components show little protein sequence homology across phyla, multiple feedback loops and light inputs are universal features of clock networks [4, 5]. Why have circadian systems evolved such a complex structure? All biological clocks entrain a set of regulatory genes to the environmental cycle, in order to correctly time the expression of many downstream processes. Thus the question becomes: What aspects of the environment, and of the desired downstream regulation, are demanding the observed complexity? To answer this, we have evolved gene regulatory networks in silico,... (More)

The 24-hour rhythms of the circadian clock [1] allow an organism to anticipate daily environmental cycles, giving it a competitive advantage [2, 3]. Although clock components show little protein sequence homology across phyla, multiple feedback loops and light inputs are universal features of clock networks [4, 5]. Why have circadian systems evolved such a complex structure? All biological clocks entrain a set of regulatory genes to the environmental cycle, in order to correctly time the expression of many downstream processes. Thus the question becomes: What aspects of the environment, and of the desired downstream regulation, are demanding the observed complexity? To answer this, we have evolved gene regulatory networks in silico, selecting for networks that correctly predict particular phases of the day under light/dark cycles. Gradually increasing the realism of the environmental cycles, we have tested the networks for the minimal characteristics of clocks observed in nature: oscillation under constant conditions, entrainment to light signals, and the presence of multiple feedback loops and light inputs. Realistic circadian gene networks are found to require a nontrivial combination of conditions, with seasonal differences in photoperiod as a necessary but not sufficient component.

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author
; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
SYSBIO
in
Current Biology
volume
19
issue
22
pages
4 pages
publisher
Elsevier
external identifiers
  • pmid:19818616
  • scopus:70450173299
ISSN
0960-9822
DOI
10.1016/j.cub.2009.09.024
language
English
LU publication?
no
id
0162eeaf-c60a-4146-bed3-b7c1fe964fc0
date added to LUP
2019-05-21 10:29:01
date last changed
2024-05-28 11:22:45
@article{0162eeaf-c60a-4146-bed3-b7c1fe964fc0,
  abstract     = {{<p>The 24-hour rhythms of the circadian clock [1] allow an organism to anticipate daily environmental cycles, giving it a competitive advantage [2, 3]. Although clock components show little protein sequence homology across phyla, multiple feedback loops and light inputs are universal features of clock networks [4, 5]. Why have circadian systems evolved such a complex structure? All biological clocks entrain a set of regulatory genes to the environmental cycle, in order to correctly time the expression of many downstream processes. Thus the question becomes: What aspects of the environment, and of the desired downstream regulation, are demanding the observed complexity? To answer this, we have evolved gene regulatory networks in silico, selecting for networks that correctly predict particular phases of the day under light/dark cycles. Gradually increasing the realism of the environmental cycles, we have tested the networks for the minimal characteristics of clocks observed in nature: oscillation under constant conditions, entrainment to light signals, and the presence of multiple feedback loops and light inputs. Realistic circadian gene networks are found to require a nontrivial combination of conditions, with seasonal differences in photoperiod as a necessary but not sufficient component.</p>}},
  author       = {{Troein, Carl and Locke, James C.W. and Turner, Matthew S. and Millar, Andrew J.}},
  issn         = {{0960-9822}},
  keywords     = {{SYSBIO}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{22}},
  pages        = {{1961--1964}},
  publisher    = {{Elsevier}},
  series       = {{Current Biology}},
  title        = {{Weather and Seasons Together Demand Complex Biological Clocks}},
  url          = {{http://dx.doi.org/10.1016/j.cub.2009.09.024}},
  doi          = {{10.1016/j.cub.2009.09.024}},
  volume       = {{19}},
  year         = {{2009}},
}