Model errors (y-axis) for mutational models with between 1 to 4 context-dependent mutational biases for vertebrate (human, D. rerio ) and non-vertebrate ( A. gambiae ) DNA and mRNA sequences. Minimum RMS distances for up to 16 additional mutational biases are shown as a dotted line. Model error reductions for alternative mutational biases are shown as unfilled circles. Mutations that remove CpG and T/UpA are shown in pink and blue inset boxes respectively. All model error values have been baseline corrected by subtraction of RMS scores of quadratic lines of best fit through observational data.