Doublet frequencies and codon weighting in the DNA ofEscherichia coli and its phages

Summary A compilation of nucleic acid sequences fromE.coli and its phages has been analysed for the frequency of occurrence of nearest neighbour base doublets and codons. Several statistically significant deviations from random are found in both doublet and codon frequencies. The deviations inE.coli also appear to occur in and in the coat protein gene of MS2, whereas T4 and other parts of the MS2 genome show different sequence properties. These and other findings are discussed in relation to the hypothesis that rapidity of translation of mRNAs in theE. coli system is dependent on doublet frequency and codon usage patterns.