highly significantP < 0.0001
The difference is highly significant, either against the null hypothesis of equal frequencies (χ 2 = 48.9529, P < 0.0001), against the expected value based on the relative number of CDSs (χ 2 = 50.3648, P < 0.0001; a slightly increased χ 2 is because E. coli has slightly fewer included CDSs than B. subtilis ), or against the expected values based on both relative number of CDSs and genomic nucleotide frequencies ( e.g. , AGAA is proportional to P A 3 P G , AGAAA to P A 4 P G , and so on, where P X is the genomic frequency of nucleotide X in either E. coli or B. subtilis ), with χ 2 = 103.07, P < 0.0001.