Ribosomal frameshift

A "ribosomal frameshift" allows alternative translation of an mRNA sequence by changing the open reading frame. This technique is commonly found in viruses, as it allows the virus to encode multiple types of proteins from the same mRNA. Frameshifting allows viruses to create many protein structures from a relatively small genome. While the ribosome is translating mRNA it may shift forward or backward, depending on the virus. Because three consecutive mRNA nucleotides make a codon that's translated into one amino acid, the frameshift makes every subsequent amino acid different because it translates a different set of codons in the new reading frame, resulting in a different protein product.