In a review, Garrigan & Hammer [34] have combined published data for Tajima’s D values from 65 autosomal loci. They find the mean value for Africans is slightly negative (-0.20) and for non-Africans is slightly positive (0.13). Overall, the values range from approximately -2 to 2. As such, we have taken Tajima’s D values above 2 or below -2 to count as extreme values, as this represents the 95% confidence interval of values in our data.
