Mutations in 5’UTR and 3’UTR
Although there are high frequencies of deletion and insertion found in the 3’-UTR (reference genome NC_045512.2: 29675 to 29903) and 5’-UTR (reference genome MN908947.3: 1 to 265) of SARS-CoV-2 genomes, the sequences are high conservative (Supplementary S4 & Figure 2A). It is worth noting that a mutation frequently appeared in -25 upstream of the ORF1ab start codon (Figure 2A). The most frequent mutation in this site is transition (C241T/U). Predicted second structure of 5’UTR showed that the mutation site is located in a little loop (Figure 2 B&C). Still, the effect of the mutation should be carefully investigated in the future. Investigating the source of the mutants, we found that most mutations were discovered in USA with later collection time.
Figure 2