 ribosomes) in fast-growing organisms and it makes sense for them to be also more accurately translated.Both hypotheses lead to highly expressed genes using mostly codons for tRNA species that are abundant in the cell.For each amino acid in a gene, the weight of each of its codons represented by a parameter termed relative adaptiveness (), is computed from a reference sequence set, as the ratio between the observed frequency of the codon and the frequency of the most frequent synonymous codon for that amino acid.