A Map of Recent Positive Selection in the Human Genome
The left-hand plot shows the probability that a 51-SNP window centered on a given SNP is in the lowest 1% of the empirical distribution for Fay and Wu's H in neutral simulated data, and in the Yoruba data overall. Notice that in neutral simulations, there is essentially no correlation between iHS and H. Right-hand plot: In contrast, in simulations with selection (cyan line, σ = 100) there is a big increase in the rate of significant H values for high-frequency selected alleles with strongly negative iHS (<−2.5). The same pattern is seen for the real data (red line). In the real data, sites with strongly positive iHS (>2.5) show an increase in the rate of positive H scores at low derived allele frequencies (magenta line). The latter probably reflects instances of an ancestral allele hitchhiking to high frequency with a selected sweep.