Figure 1: Estimation of mutation rate of SARS-COV2 in human. A) Average nucleotide differences for each month were calculated by mean of all sequences analyzed for that month.  In April, it substituted 11.94 (~12) nucleotides from December, 2019.  B) Mutation rate is plotted against each month. C) Alignment of five key entry point residues in ACE2 protein of various animals. SARS-COV2 shows poor infectivity due to absence of K353 in mouse and rat.