Distribution of single-feature polymorphisms. (a) The observed d-statistics (y-axis) is plotted against the expected d-statistics (x-axis) as determined by permutations. 10,504 significant SFPs exceeding the threshold of 0.1% FDR are shown in green. (b) Histogram of d-statistics truncated at ± 10. Positive scores above the threshold 3.38 are Golden Promise SFPs, and negative scores below -3.37 are Morex SFPs.