An expanded codon table showing the relative frequence that different codons are used in E. coli genes

Genes are clustered by using factorial correspondence analysis into three classes. Class I contains genes involved in most metabolic processes. Class II genes correspond to genes highly and continuously expressed during exponential growth. Class III genes are implicated in horizontal transfer of DNA.

On online tool to count codons

Correspondence Analysis of Codon Usage

FREQSQ calculates the frequences (in number or/and in percentage) of bases, dinucleotides, codons or potential amino acid of a nucleic sequence.

This server performs several computations in relation to codon usage and the codon adaptation of DNA or RNA sequences to host organisms.

OPTIMIZER is an on-line application that optimizes the codon usage of a DNA sequence to increase its expression level.

The Codon Adaptation Tool (JCAT) presents a simple method to adapt the Codon Usage to most sequenced prokaryotic organisms and selected eukaryotic organisms. The codon adaptation plays a major role in cases where foreign genes are expressed in hosts and the codon usage of the host differs from that of the organism where the gene stems from.

This server performs several computations in relation to codon usage and the codon adaptation of DNA or RNA sequences to host organisms.