A Map of Recent Positive Selection in the Human Genome
Simulation parameters are matched to the Yoruba data, with σ = 150. Tests are abased on 51-SNP windows centered on a selected site. The upper curves (iHS) are based on counting the number of SNPs in the window for which |iHS| >2. The green line indicates power when the actual SNP under selection is excluded from the analysis. The lower lines plot power using Fay and Wu's H, and Tajima's D, both calculated using the ascertained genotype data. The line marked t = +200 indicates the power 200 generations after fixation (Ne = 104). Critical values for each statistic at p = 0.01 were obtained using identical simulations with σ = 0.