Kernel density plots of the interval length between adjacent windows of introgressed genomic blocks (100 kb). The type of introgression is shown in c and for each tree topology, 100 windows were sampled randomly as a control. One-sided Wilcoxon test; left to right, n = 43, 109, 63, 136, 71, 62. In box plots, the centre line is the median, the box limits show the interquartile range (25th to 75th percentile), whiskers extend to quartiles 1.5 interquartile range, and dots show potential outliers.
