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Published on: August 15, 2019
On epistasis: why it is unimportant in polygenic directional selection
1Genetics Laboratory, University of Wisconsin, , Madison, WI 53706, USA. jfcrow@wisc.edu
Summary
Developmental geneticists study genes with large effects, while breeders focus on quantitative traits influenced by many genes. Breeders’ methods, often ignoring epistasis, provide more accurate predictions for quantitative trait evolution.
Area of Science:
- Evolutionary genetics
- Quantitative genetics
- Developmental biology
Background:
- Differing perspectives exist between developmental/evo-devo geneticists and breeders/quantitative evolutionists.
- Developmental genetics focuses on individual genes with large effects, including dominance and epistasis.
- Quantitative evolution studies traits influenced by multiple genes with minimal dominance or epistasis.
Purpose of the Study:
- To highlight the contrasting approaches in genetic research.
- To explain the differing methodologies and assumptions in developmental genetics versus quantitative genetics and breeding.
Main Methods:
- Conceptual comparison of research focuses and genetic models.
- Analysis of the impact of gene effects (large vs. small), dominance, and epistasis on trait evolution.
Main Results:
- Developmental genetics emphasizes gene interactions and large individual gene effects.
- Quantitative genetics and breeding focus on additive genetic variance for predicting trait changes.
- Epistatic variance has minimal long-term impact in selected populations, validating breeder practices.
Conclusions:
- Breeders' practice of ignoring epistasis offers more accurate predictions for quantitative trait evolution.
- Understanding the distinct genetic architectures is crucial for advancing both fields.
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