Figure 2.

Distribution of ratio of divergence between D. melanogaster-D. simulans versus D. yakuba-D. erecta. (a) Distribution of molecular-divergence log₂ (d _N1/d _N2) to divergence-time ratio log₂ (T ₁/T ₂), between D. melanogaster-D. simulans and D. yakuba-D. erecta. Colored circles represent d _N ratios, and gray circles represent d _S ratios. The upper limit of the clockwise category is given by the log₂ ratio of divergence times (6.5/8.1) and the lower limit by the log₂ ratio 4.3/12.7. (b) Relationship of d _N between D. melanogaster-D. simulans and D. yakuba-D. erecta. The regression lines for each rate categories are also plotted. (c) Relationship of d _S between D. melanogaster-D. simulans versus D. yakuba-D. erecta; color codes: red: accelerated, black: clock-like, green: slow-rate categories, and grey: d _S ratios.