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Updated: May 5, 2026
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Following the Dynamics of Structural Variants in Experimentally Evolved Populations
Published on: February 3, 2023
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Effects of disruptive selection on genetic variance
1Institute of Animal Genetics, West Mains Road, EH9 3JN, Edinburgh, Scotland.
Summary
Disruptive selection increases genetic variance, primarily through linkage disequilibrium, even with few genes. This variance then decreases with random mating, confirming theoretical models.
Area of Science:
- Evolutionary genetics
- Quantitative genetics
Background:
- Theoretical models of disruptive selection often assume infinite genes, attributing variance changes solely to linkage disequilibrium.
- Limited empirical data exists for genetic variance changes with few loci under disruptive selection.
Purpose of the Study:
- To investigate the role of linkage disequilibrium in changes of genetic variance under disruptive selection with a limited number of loci.
- To experimentally test theoretical predictions using Drosophila melanogaster.
Main Methods:
- A replicated experiment with Drosophila melanogaster subjected to three generations of disruptive selection.
- Subsequent generations (5 or 7) of random mating to observe variance changes.
- Estimation of heritability using regression of progeny on parent.
Main Results:
- Heritability increased from 37% to 68% during disruptive selection.
- Heritability declined to 45% after random mating.
- Observed variance changes align with the build-up and breakdown of linkage disequilibrium.
Conclusions:
- Linkage disequilibrium plays a major role in variance changes under disruptive selection, even with few loci.
- Experimental results support theoretical predictions and Monte Carlo simulations.
- The dynamics of genetic variance are influenced by the interplay of selection and mating systems.
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