The degree of mutational bias correlates with position within the gene and with coding sequence length. (A) There is a gradient in the frequency of GARP (top) and FYMINK (bottom) amino acids along the encoded proteins. A sliding window of 17 amino acids was used to score the frequency of GARP and FYMINK along the first 350 amino acid positions. (B) The relationship between coding sequence length and G+C content. On the left, the average lengths and 99% confidence intervals are shown for the low G+C rice genes and their Arabidopsis homologs. The corresponding data for the high G+C rice genes are shown on the right