The E-CAI server is a web-application and an executable program that calculates the expected value of the Codon Adaptation Index (CAI) for a set of query sequences by generating random sequences with similar G+C content and amino acid composition to the input. This expected CAI therefore provides a direct threshold value for discerning whether the differences in the CAI value are statistically significant and arise from the codon preferences or whether they are merely artifacts that arise from internal biases in the G+C composition and/or amino acid composition of the query sequences.

URL

E-CAI is freely accessible at http://genomes.urv.cat/CAIcal/E-CAI

For more details see the article Puigbò P, Bravo IG and Garcia-Vallvé S. E-CAI: a novel server to estimate an expected value of Codon Adaptation Index (eCAI). BMC Bioinformatics 2008, 9:65