New properties of the two-locus partial selfing model with selection.

Area of Science:

• Population Genetics
• Evolutionary Biology
• Quantitative Genetics

Background:

• Heterotic selection models are crucial for understanding genetic variation maintenance.
• Mixed selfing and random outcrossing influence population genetic dynamics.
• Gametic disequilibrium is a key factor in evolutionary processes.

Purpose of the Study:

• To derive analytic solutions for equilibria in a two-locus selection model with mixed selfing.
• To introduce and analyze a new measure of gametic disequilibrium potential, Delta(s).
• To investigate the effects of partial selfing on genetic disequilibrium and mean fitness.

Main Methods:

• Analytic solutions for equilibrium states.
• Mathematical modeling of a two-locus heterotic selection model.
• Numerical examination of model outcomes under varying selfing rates and linkage.

Main Results:

• Two phenomena are identified: negative disequilibrium potential (only gametic disequilibrium possible) and positive disequilibrium potential (permanent gametic disequilibrium possible with tight linkage).
• Partial selfing alters the relationship between disequilibrium potential and epistasis compared to random mating.
• New properties of partial selfing emerged: equilibrium mean fitness correlates inversely with recombination under negative Delta(s) and directly under positive Delta(s).
• Gametic disequilibrium can either increase or decrease with increasing selfing rates.

Conclusions:

• Partial selfing and linkage are not analogous in their effects on maintaining disequilibrium.
• The measure Delta(s) provides a more accurate assessment of disequilibrium potential under partial selfing.
• Understanding these dynamics is vital for predicting evolutionary trajectories and the persistence of genetic variation.