Figure 5.

Several features of nucleotide bias around the initiation codon. (A) Nucleotide bias around the initiation codon for genes expressed at high and low levels in humans (left) and S. cerevisiae (right). The diagram for each species shown at the left is the same as that in Figure 2. The middle and right diagrams for each species were calculated by using the top 1000 genes with higher expression levels and the bottom 1000 genes with lower expression levels, respectively, in each species. (B) Three-base periodicity observed in humans (left) and Oryza sativa (right). Arrows indicate every three bases. (C) U- and A-rich biases observed at positions around −40 and around −15, respectively, which are indicated by arrows. The g_n values are shown from positions −100 to −1 for Xenopus laevis, Danio rerio, D. melanogaster and Anopheles gambiae.