Fig. 1

The schematic and an example of the identification of compensatory frameshift cases in RNA virus genomes. a A procedure was developed to identify compensatory frameshift cases in the RNA virus genome. By analyzing 10,115 RefSeq CDS sequences and 1,233,275 viral genome sequences, a total of 194 CDS clusters were identified as having at least one compensatory frameshift form. b An example compensatory frameshift case found in the PorPV matrix protein is presented. Five PorPV matrix protein CDS sequences were classified into the reference form (“Ref”; two sequences) and a compensatory frameshift form (“Comp”; three sequences). A box indicates the region where the compensatory frameshift was identified. The red line indicates the frameshifted segment using an alternative reading frame in the compensatory frameshift form compared to the reference form. c A part of the multiple alignment of PorPV matrix protein CDS sequences is shown. The 1-nt deletion (open triangle) and 1-nt insertion (filled triangle) in the compensatory frameshift form sequences (accession numbers in red) are marked. The frameshifted segments are in red. d A part of multiple alignment of PorPV matrix protein sequences is shown. The 6-aa frameshifted segment is in red