Figure 5

ω of branches according to the ratio of synonymous mutations. (a) ω of internal branches of UP clusters (red) and all branches of SO clusters (green) is plotted against the rate of synonymous mutations of sequences. As the point density is too high, each point represents the mean of 100 values. (b) The p-value of the Mann–Whitney test according to the synonymous substitution rate. This statistical test is performed using all the ω data and on intervals of 0.01 and contains at least 25 values. The dotted blue line is the significance level fixed at 0.05.