Figure 1.

Evolutionary rates of enhancers. Rates of evolution calculated for mouse enhancers of embryonic forebrain (FB), midbrain (MB), limb (LM), and heart (HT), included D (A), normalized evolutionary rates D/d₄ (B) or D/d_i (C), and neutral substitution rates d₄ (D) or d_i (E). The values of upper quartile, median, and lower quartile are indicated in each box, whereas the bars outside the box indicate semi-quartile ranges. D, D/d₄, D/d_i, d₄ and d_i were computed based on mouse-rat alignments. Pairwise comparisons showing significant differences in D, D/d₄, D/d_i, d₄, or d_i are connected with gray lines (Mann-Whitney U test).