Frameshift mutation
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- For the progressive rock/metal band, see Frameshift (band)
A frameshift mutation (also called a frameshift or a framing error) is a genetic mutation that 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 gene the deletion or insertion occurs, the more altered the gene product 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 most likely not be functional.
Frameshift mutations frequently result in severe genetic diseases. A frameshift mutation is responsible for the disabling of the CCR5 HIV receptor and some types of familial hypercholesterolemia (Lewis, 2005, p. 227-228). Frameshift mutations can also be beneficial, proven to be an advantage to cancer survival.
[edit] Reference
Lewis R. 2005. Human Genetics: Concepts and Applications, 6th Ed. McGraw Hill, New York.
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