A general model to explore complex dominance patterns in plant sporophytic self-incompatibility systems

Area of Science:

• Population Genetics
• Evolutionary Biology
• Plant Reproductive Biology

Background:

• Sporophytic self-incompatibility (SSI) is a crucial genetic mechanism regulating plant reproduction.
• Understanding SSI requires models that account for complex dominance relationships among alleles.
• Previous models often simplified dominance patterns, limiting their applicability to diverse species.

Purpose of the Study:

• To develop a general deterministic model of SSI incorporating complex allele dominance.
• To investigate how factors like dominance classes, allele numbers, and selection asymmetry affect equilibrium allele frequencies.
• To evaluate the model's predictive power using empirical data from natural populations.

Main Methods:

• Developed a deterministic mathematical model for SSI with variable dominance.
• Analyzed the impact of dominance class number, alleles per class, and selection asymmetry on allele frequencies.
• Compared model predictions with observed allelic frequencies in two plant species.

Main Results:

• The 'recessive effect' is a common outcome across various dominance scenarios.
• Higher allele numbers are maintained in more dominant classes; dominance classes can evolve.
• Significant proportions of homozygous genotypes can exist for highly recessive alleles.

Conclusions:

• The developed SSI model accurately captures complex dominance patterns and predicts allele dynamics.
• Model predictions align with observed allelic frequencies in natural populations, validating its utility.
• The model serves as a framework for detecting additional, allele-specific selective pressures in SSI systems.