Figure 6.

Selective constraints on the six species of the melanogaster group of Drosophila. Numbers above branches (in red) show the estimates of the ω parameter (ω = nonsynonymous substitution rate [d_N]/synonymous substitution rate [d_S]). Numbers below branches indicate the d_N (in black) and d_S (in blue) values, respectively. The ω values were calculated applying the free ratio (FR) model on the concatenated multiple alignment (set of 42 orthologous groups).