The Codon Adaptation Index (CAI) was first developed to measure the synonymous codon usage bias for a DNA or RNA sequence. The CAI quantifies the similarity between the synonymous codon usage of a gene and the synonymous codon frequency of a reference set.
Department of Biochemistry and Biotechnology, Rovira i Virgili University (URV), Campus Sescelades, c/Marcelli Domingo s/n, 43007 Tarragona, Spain. puigboap@ncbi.nlm.nih.gov
