The many-demes limit for selection and drift in a subdivided population

Area of Science:

• Population Genetics
• Mathematical Biology
• Evolutionary Dynamics

Background:

• Understanding allele frequency dynamics is crucial in population genetics.
• Previous models often simplified population structures, neglecting complex migration patterns.

Purpose of the Study:

• To derive a diffusion approximation for allele frequencies in a many-demes population.
• To analyze the impact of migration and selection on genetic drift across subpopulations.

Main Methods:

• Developed a diffusion approximation for allele frequency.
• Assumed weak selection inversely proportional to the number of demes.
• Analyzed the statistical equilibrium between migration and drift.

Main Results:

• The diffusion process is similar to unstructured populations but on a longer timescale with restricted migration.
• The model holds for positive migration rates and any deme sizes.
• Described the distribution of allele frequencies across demes.

Conclusions:

• Restricted migration significantly impacts the timescale of allele frequency changes in subdivided populations.
• The many-demes diffusion limit provides a robust framework for studying genetic variation.
• The findings are relevant for understanding evolutionary processes in structured populations.