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Testing the rare-alleles model of quantitative variation by artificial selection
1Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Ave, Lawrence, KS, 66045-7534, USA. jkk@ku.edu
Genetica
|July 4, 2007
Summary
Artificial selection experiments on Mimulus guttatus flower size support the rare-alleles model of quantitative variation. Genetic variance increased with selection for larger flowers, consistent with rare, partially dominant alleles influencing the trait.
Area of Science:
- Evolutionary genetics
- Quantitative genetics
Background:
- The rare-alleles model suggests quantitative traits are influenced by common wild-type alleles and rare alleles.
- Evolutionary hypotheses predict artificial selection should increase genetic variance (Vg) if this model is accurate.
Purpose of the Study:
- To test the 'DeltaVg prediction' of the rare-alleles model using artificial selection.
- To investigate the genetic basis of quantitative variation in Mimulus guttatus flower size.
Main Methods:
- A large-scale artificial selection experiment was conducted on Mimulus guttatus flower size.
- Changes in genetic variance (Vg) were measured under directional selection.
Main Results:
- Genetic variance for flower size evolved significantly, increasing with selection for larger flowers and decreasing with selection for smaller flowers.
- Observed changes in Vg are consistent with rare, partially dominant alleles contributing to flower size variation.
Conclusions:
- The study provides evidence supporting the rare-alleles model for quantitative trait variation.
- Further research combining marker-based mapping and biometric techniques is needed to fully elucidate allele frequency distributions at quantitative trait loci.
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