Partial Selfing Can Reduce Genetic Loads While Maintaining Diversity During Experimental Evolution

Area of Science:

• Evolutionary biology
• Population genetics
• Genomics

Background:

• Partial selfing, a mix of self and cross-fertilization, is evolutionarily unstable but observed in nature.
• This mode may balance purging genetic load with maintaining adaptive genetic diversity.

Purpose of the Study:

• To investigate the evolutionary stability and adaptive potential of partial selfing.
• To compare genetic load and diversity under partial selfing, exclusive selfing, and predominant outcrossing.

Main Methods:

• Experimental evolution of *Caenorhabditis elegans* populations.
• Adaptation to osmotic stress.
• Analysis of genome-wide single-nucleotide polymorphisms (SNPs) and inbreeding depression.

Main Results:

• Genetic load was reduced in partial and exclusive selfing but maintained in predominant outcrossing.
• Populations under partial selfing and predominant outcrossing retained higher genetic diversity than expected.
• Deleterious alleles and overdominant loci may explain maintained diversity.

Conclusions:

• Partial selfing can reduce genetic load while preserving crucial genetic diversity for adaptation.
• This mode offers benefits of purging deleterious alleles and maintaining variation at overdominant loci.