Fig. 6

Comparison of base-pair transformations to GC and AU in ITS2 transition-rate matrices using the best-fit RNA substitution models. The transition rate for each matrix was normalized to an average substitution rate of 1.0. A-D Base-pair transformations derived from the initial states of 142 ITS2 transition-rate matrices, A,B The relative rates of the six possible transformations to GC and AU, respectively. C Comparison of the total formation rates for GC and AU base pairs. D Scatter plot showing the frequency-mutability relationship of formation rates for GC and AU base pairs, indicating an increased fixation of GC with GC enrichment. E-H base-pair transformations derived from the equilibrium states of 46 ITS2 transition-rate matrices. E,F The relative rates of the six possible transformations to GC and AU, respectively. G Comparison of the total formation rates for GC and AU base pairs. H Scatter plot illustrating the frequency-mutability relationship of formation rates for GC and AU base pairs, indicating an increased fixation of GC with GC enrichment