Plots of LD decay over distance for 4 immunity genes in An. gambiae s.l.. Each data point represents a pairwise measure of r2 as a function of nucleotide distance (bases). An. gambiae M form (black), An. gambiae S form (blue), An. arabiensis (red), An. bwambae (green), An. melas (purple), An. merus (orange) and An. quadriannulatus (yellow). LD decay curves are fitted by the gam function in the mgcv package, using default options.