Figure 3:

Model of possible RNA editing-induced mutational bias in SARS-CoV-2 evolution. A. Nucleotide substitution frequencies at synonymous sites in branches from the most recent common ancestor of SARS-CoV-2 and RaTG13 (the purple point in the phylogenetic tree on the left) to SARS-CoV-2 (B1) and RaTG13 (B2). B. A-to-I editing events catalyzed by ADARs in the sense or antisense strand of SARS-CoV-2 cause A-to-G or U-to-C mutations (upper panel); C-to-U editing catalyzed by APOBECs in the sense or antisense strand of SARS-CoV-2 cause C-to-U or G-to-A mutations (lower panel).