Change in genetic variance under selection in a self-fertilizing population

Area of Science:

• Quantitative genetics
• Population genetics

Background:

• Understanding genetic variance changes is crucial for predicting trait evolution.
• Self-fertilization and selection significantly impact genetic diversity within populations.

Purpose of the Study:

• To analyze the dynamics of genetic variance for quantitative traits in self-fertilizing populations under repeated truncation selection.
• To investigate the role of linkage disequilibrium in reducing genetic variance.

Main Methods:

• Utilized the infinitesimal model assuming an infinite number of unlinked loci without epistasis.
• Employed genotypic frequency dynamics to track changes in linkage disequilibrium and genetic variance.
• Derived recurrence relations for genetic variance under different gene action models.

Main Results:

• Genetic variance reduction is primarily driven by the build-up of linkage disequilibrium, not genotypic frequency changes.
• Recurrence relations were established for purely additive gene action, pure dominance, and combined additive-dominance effects.
• Numerical examples validated the derived recurrence formulas.

Conclusions:

• Truncation selection in self-fertilizing populations leads to decreased genetic variance through induced linkage disequilibrium.
• The derived recurrence relations provide a framework for predicting genetic variance changes across generations.
• The infinitesimal model offers insights into the complex interplay of selection, self-fertilization, and genetic architecture.