RESPONSE TO SELECTION IN PARTIALLY SELF-FERTILIZING POPULATIONS. I. SELECTION ON A SINGLE TRAIT

Area of Science:

• Evolutionary Biology
• Quantitative Genetics
• Plant Reproduction

Background:

• Self-fertilization is prevalent in plants, significantly impacting the evolution of quantitative traits.
• Existing models often simplify or exclude the full spectrum of selfing rates.
• Understanding the interplay between mating systems and trait evolution is critical.

Purpose of the Study:

• To develop a flexible model that accommodates any level of self-fertilization for quantitative trait evolution.
• To predict the evolutionary trajectory of the mean phenotype based on genetic and mating system parameters.
• To investigate the influence of selfing on genetic variance and linkage disequilibrium.

Main Methods:

• Development of the structured linear model (SLM).
• Stochastic simulations of truncation selection across a range of selfing rates.
• Analysis of the model's accuracy in predicting changes in trait mean and variance.
• Examination of inbreeding coefficients and linkage disequilibrium dynamics.

Main Results:

• The SLM accurately predicts the evolution of quantitative traits under varying self-fertilization levels.
• Selfing significantly magnifies the Bulmer effect (changes in genetic variance due to linkage disequilibrium).
• Complex interactions between selection and mating systems influence inbreeding patterns and linkage disequilibrium.

Conclusions:

• The structured linear model provides a robust framework for studying trait evolution with self-fertilization.
• Selfing introduces complexities in the relationship between mating systems and response to selection.
• Model parameters can be estimated from phenotypic data, facilitating empirical application.