Evolution of recombination due to random drift

Area of Science:

• Population Genetics
• Evolutionary Biology

Background:

• Genetic drift in finite populations can generate negative linkage disequilibrium.
• Negative linkage disequilibrium reduces fitness variance, impeding adaptive evolution by slowing the rate of increase in mean fitness.

Purpose of the Study:

• To investigate how stochastic fluctuations in linkage disequilibrium favor the evolution of increased recombination rates.
• To quantify the selection acting on modifier alleles that increase recombination in finite populations.

Main Methods:

• Theoretical analysis of selection on recombination modifiers.
• Monte Carlo simulations to confirm analytical predictions.

Main Results:

• Stochastic linkage disequilibrium in finite populations favors increased recombination.
• Selection for increased recombination is strongest with tight linkage, rising beneficial alleles, and small population sizes.
• The developed method quantifies selection on recombination modifiers.

Conclusions:

• Finite population size and genetic drift can drive the evolution of higher recombination rates.
• Recombination modifiers that alleviate negative linkage disequilibrium can increase in frequency via hitchhiking.
• The findings highlight the interplay between drift, selection, and recombination in shaping genome evolution.