
Codon alignments of retroelements with similar −1 frame cassettes in the overlap region between gag and pol. Panels A–D correspond to the four groups of retroelements depicted in Figure 1 that have pol in the −1 frame relative to gag. Sequences with greater than 75% identity are highlighted. Possible locations for tRNAs during frameshifting are marked by AAA (A-site), PPP (P-site), and EEE (E-site).










