For the progressive rock/metal band, see Frameshift
A frameshift mutation (also called a frameshift or a framing error) is a genetic mutation caused by indels, ie. inserts or deletes a number of nucleotides that is not evenly divisible by three from a DNA sequence. Due to the triplet nature of gene expression by codons, the insertion or deletion can disrupt the reading frame, or the grouping of the codons, resulting in a completely different translation from the original. The earlier in the sequence the deletion or insertion occurs, the more altered the protein produced is.A frameshift mutation causes the reading of codons to be different, so all codons after the mutation (with a few exceptions due to redundancy) will code for different amino acids. Furthermore, the stop codon "UAA, UGA, or UAG" will not be read, or a stop codon could be created at an earlier site. The protein being created could be abnormally short, abnormally long, and/or contain the wrong amino acids. It will
Source:
http://en.wikipedia.org/wiki/Frameshift