Fig. 4

Differences in nucleotide composition between SARS-CoV-2 and human-CoV. a Values for the square of the difference in mononucleotide composition between SARS-CoV-2 isolated in each month and human-CoV are plotted against the elapsed month. The data are presented as colored or dashed lines, as described in Fig. 1. (b and c) Oligonucleotide compositions that approach and move from those of human-CoV are presented, respectively. d The correlation coefficients between the elapsed month from the start of the epidemic and the above differences in mono- and oligonucleotides whose directionality of change is common among six clades are presented. The results for A and G mononucleotides, which show nondirectional change, are also presented