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Wright's shifting balance theory: an experimental study
1Department of Ecology and Evolution, University of Chicago, IL 60637.
Science (New York, N.Y.)
|August 30, 1991
Summary
This study experimentally confirms Wright's shifting balance theory of evolution using flour beetles. Interdemic selection, a key component, significantly increased population fitness, supporting adaptive evolution.
Area of Science:
- Evolutionary Biology
- Population Genetics
Background:
- Wright's shifting balance theory is a cornerstone of adaptive evolution.
- Direct empirical evidence and the efficacy of interdemic selection remain controversial.
Purpose of the Study:
- To provide experimental confirmation of Wright's shifting balance theory.
- To investigate the role and effectiveness of interdemic selection in adaptive evolution.
Main Methods:
- Imposed interdemic selection on Tribolium castaneum laboratory populations.
- Differential dispersion of individuals from high-fitness to low-fitness demes.
- Compared experimental arrays to control populations with random migration.
Main Results:
- Significant increase in average population fitness in experimental arrays.
- Optimal response observed with interdemic selection every two generations.
- Gene interactions are suggested to be involved in the observed fitness increase.
Conclusions:
- The interdemic phase of shifting balance theory can enhance average fitness.
- Experimental evidence supports the adaptive potential of interdemic selection.
- Further research into gene interactions underlying this process is warranted.
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