Distinct Patterns of Selective Sweep and Polygenic Adaptation in Evolve and Resequence Studies

Area of Science:

• Evolutionary Biology
• Population Genetics
• Genomics

Background:

• Adaptation is studied through selective sweep (independent loci) and polygenic adaptation (many loci) models.
• Existing methods primarily focus on the phenotype, lacking clear differentiation of selection signatures between models.
• Both models can produce similar genomic signatures, necessitating new criteria for distinction.

Purpose of the Study:

• To investigate and compare the genomic patterns of selected alleles under selective sweep and polygenic adaptation models.
• To identify distinct signatures that can differentiate between these two major modes of adaptation.
• To provide a foundation for developing quantitative approaches to distinguish between selective sweep and polygenic adaptation.

Main Methods:

• Computer simulations were employed within an experimental evolution framework.
• Two models were simulated: selective sweep (independent beneficial mutations) and trait optimum (polygenic adaptation under stabilizing selection).
• Patterns of selected alleles were analyzed across populations of varying sizes.

Main Results:

• Distinct genomic patterns were identified for selective sweep and trait optimum models.
• These patterns varied depending on population size.
• The findings highlight key differences in allele frequency changes under the two models.

Conclusions:

• The study successfully identified unique genomic signatures for selective sweep and polygenic adaptation.
• These identified features can be used to develop quantitative methods for distinguishing between adaptation models.
• Experimental evolution simulations provide a powerful framework for understanding evolutionary processes.