Figure 3

Comparative analysis of total intron length in P. glauca , A. thaliana, P. trichocarpa and Z. mays . Average ratio of total length of intron sequences in pair-wise comparisons in: A- all genes; B- highly expressed genes and genes involved in secondary cell-wall formation and nitrogen metabolism (For individual ratios, see Figure 4). The total intron lengths were compared among the four species by Kruskal-Wallis test with post-test analysis by Dunn’s multiple comparisons: NS, not significant (P ≥ 0.05); **P < 0.01; ***P < 0.001.