< Back to Article

Translational Selection Is Ubiquitous in Prokaryotes

Figure 5

Preferred codons in OCU genes.

Height of bar segments indicates the number of genomes in which the putatively translationally optimal or suboptimal codon is more frequent in the OCU genes vs. the non-OCU genes, broken down by amino acid. An optimal codon may be determined for a two-fold degenerate amino acid in cases when a genome codes only for tRNAs with one specific anticodon. The codon that directly matches this anticodon is then declared to be putatively optimal and is almost always C- or A-ending; the other codon is putatively suboptimal. Preference for a codon is determined by a Mann-Whitney U test on OCU vs. non-OCU codon frequencies at p<10−3. Shown p values are by sign test under the null hypothesis that OCU genes are equally likely to prefer optimal or suboptimal codons.

Figure 5