Population Genetics of Polymorphism and Divergence Under Fluctuating Selection

摘要: Current methods for detecting fluctuating selection require time series data on genotype frequencies. Here, we propose an alternative approach that makes use of DNA polymorphism from a sample individuals collected at single point in time. Our method uses classical diffusion approximations to model temporal fluctuations the coefficients find expected distribution mutation frequencies population. Using Poisson random-field setting derive site-frequency spectrum (SFS) three different models selection. We general effect is produce more “U”-shaped with excess high-frequency derived mutations expense middle-frequency variants. present likelihood-ratio tests, comparing neutral using SFS data, and Monte Carlo simulations assess their power. have sufficient power reject hypothesis samples order few hundred SNPs size ∼20 distinguish between varies constant 20. also increases probability fixation selected sites even if, average, there no difference among pair alleles segregating locus. Fluctuating will, therefore, lead increase ratio divergence similar observed under positive directional