Table 1.

Libraries/Packages in Python Used for Plots or Statistical Analyses.

Library/Package	Plot/Statistical Test	Figures	Notes
Seaborn(v 0.11.2)	Line plot	Figure 1a and b; supplementary figures 2 and 3, Supplementary Material online	Percentages of mononucleotides and dinucleotides were plotted along a time axis of 1-month intervals. Since each month corresponds to several sequences, a band was plotted along with the mean value to depict the range of values in the 95% CI.
	Violin plot	Figures 1c and d, 3, 4c, 5c and d, 6, and 7; Supplementary figure 4, Supplementary Material online	The horizontal lines in the violin plots depict the lower quartile, the median, and the upper quartile.
	Box-and-Whisker plot	Figure 4b	The box shows the quartiles of the data set whereas the whiskers extend to show the rest of the distribution, except for points that are determined to be “outliers” using a function of the interquartile range.
SciPy.stats(v 1.7.1)	Mann–Whitney U test	Figures 1c and d, 3, 4c, 5c and d, 6, and 7; Supplementary figure 4, Supplementary Material online	P < 0.05 was considered significant.
	Kruskal–Wallis H test	Figure 7	P < 0.05 was considered significant.
Matplotlib(v 3.4.2)	Scatter plot	Figures 4a and 5a and b; Supplementary figure 1b, Supplementary Material online	In figure 4a, CpGs sites corresponding to the first 100 nt and last 100 nt of the reference sequence for SARS-CoV-2 were excluded from analysis to eliminate any potential bias caused by either increased number of Ns at the 5′ or 3′ ends.
Matplotlib(v 3.4.2)	Line plot	Figure 2 and supplementary figure 1, Supplementary Material online	See calculations for details.