Selfing, adaptation and background selection in finite populations.

Area of Science:

• Evolutionary genetics
• Population genetics
• Genomic evolution

Background:

• Classic genetic models predict obligate outcrossing or selfing.
• Observed low-level outcrossing in high selfing species contradicts these models.
• Hill-Robertson effects, the interaction between drift and selection, are often ignored.

Purpose of the Study:

• Investigate the role of Hill-Robertson effects in the evolution of selfing.
• Determine if low levels of outcrossing can be adaptive.
• Model the interplay between selfing, recombination, and adaptation.

Main Methods:

• Multilocus population genetic simulations.
• Analysis of genetic disequilibrium under varying selfing rates.
• Evolutionary simulations of selfing rates.

Main Results:

• Selfing reduces effective population size and increases negative genetic disequilibrium.
• Adaptation rates are significantly reduced in strong selfers.
• Populations evolve towards extreme outcrossing or selfing, with low outcrossing maintained in selfers under specific conditions.

Conclusions:

• Low levels of outcrossing can be selectively favored in selfing populations to counteract negative disequilibrium.
• The rate of deleterious mutation influences the maintenance of outcrossing.
• Interactions between beneficial mutations and selfing can quantitatively alter outcrossing rates.