Figure 2.

Distribution function of d_N/d_Sin usp for five extant groups of insects. The curves describe the estimated proportion of codons that have d_N/d_S ratios at a value less than or equal to a particular value on the abscissa. β distributions were compared by Kolmogorov-Smirnov tests. The β-distribution parameters were estimated for the M7 model, or M8 if statistically superior to M7 (see Table  2). Drosophilidae: red; Diptera: purple; Lepidoptera: orange; Tenebrionidae: green; Blattaria: blue.