Figure 4. Central 99% Range of Unstandardized iHS for SNPs in the Yoruba Data and for SNPs in Matched Neutral Simulations.

The upper and lower lines mark the boundaries of the central 99% distribution of the unstandardized iHS ratio, as a function of derived allele frequency. The gray lines plot results for a range of plausible demographic models. The fatter tails in the real data are consistent with the action of selection.