where XY a-b N is the total number of breakpoints characterized for the RWXY a-b pair, and 50 is the size in nucleotides of the sliding window, and F the frequency of recombination observed in the whole region studied, as defined in the previous chapter. The sliding window was then displaced with a 10 nucleotides increment (resulting in XY a-b Sw i+10 , XY a-b Sw i+20 , … ) across the recombination window, and XY a-b R i+10 , XY a-b R i+20 , … were computed. The various R values were reported in the graph as a function of the position of the midpoint of the window along the gene (i.e. the position of the 25 th nucleotide of each sliding window). For the pooled dataset reported in Figure 2B , the analysis based on the sliding window was repeated. If Swp i stands for the sliding window at position i for the pooled dataset, Rp i for the corresponding recombination rate, and q is the number of recombination window including position i, recombination rate at position i is calculated as