The most biased codon-pair contexts.

In order to identify the strongest bias in codon-pair contexts they were ranked according to their residual values in Eubacteria, Archaea and Eukaryota. The 10 lowest or highest residuals obtained in each group are shown. Codon-pair contexts that appeared in more than one group are underlined, while codon-pair contexts of identical codons are shown in bold. Eubacteria showed the highest codon-pair biases since the amplitude of the adjusted residuals varied between ?309 and 921. Interestingly, 9 out of the 10 highest residuals of eukaryotic ORFeomes corresponded to codon-pair contexts formed by identical codons in both positions (in bold).