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Related Experiment Video

Updated: Jul 17, 2026

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180&#176; Curved Artery Test Section
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Published on: July 19, 2016

Circadian rhythms: in the loop at last.

Russell N Van Gelder1, Erik D Herzog, William J Schwartz

  • 1Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, MO 63110, USA. vangelder@vision.wustl.edu

Science (New York, N.Y.)
|June 7, 2003
PubMed
Summary

Animal circadian clocks use similar molecular feedback loops, but employ different genes in mammals and fruit flies. This comparison highlights conserved principles and divergent molecular players in biological timekeeping.

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Area of Science:

  • Chronobiology
  • Molecular Biology
  • Comparative Genomics

Background:

  • Circadian oscillators are fundamental biological processes conserved across species.
  • These oscillators typically rely on negative feedback loops involving clock gene products.
  • Animal circadian clocks integrate at least two interacting feedback loops for robust oscillation.

Purpose of the Study:

  • To compare and contrast the molecular mechanisms of circadian clocks in mammals and Drosophila.
  • To elucidate how different molecular players execute a conserved circadian regulatory script.
  • To highlight evolutionary divergence and convergence in biological timekeeping systems.

Main Methods:

  • Comparative analysis of known mammalian and Drosophila circadian clock gene pathways.
  • Review of existing literature on molecular components and interactions.
  • Utilizing resources from Science's Signal Transduction Knowledge Environment.

Main Results:

  • Both mammals and Drosophila utilize oscillating feedback loops for circadian rhythm generation.
  • Despite a shared basic script, distinct sets of genes and proteins form these loops in each group.
  • Key differences exist in the specific molecular players driving the negative feedback mechanisms.

Conclusions:

  • The fundamental principles of circadian timekeeping are conserved across diverse animal taxa.
  • Evolution has shaped distinct molecular solutions to implement conserved circadian functions.
  • Understanding these comparative pathways provides insights into the robustness and adaptability of biological clocks.