What is a frameshift mutation?

A frameshift mutation specifically involves the insertion or deletion of nucleotides in a DNA sequence that is not a multiple of three. This alteration changes the way the sequence is read during translation, meaning that all subsequent codons from the point of mutation are affected. As a result, this can lead to significant changes in the resulting protein, potentially altering its structure and function dramatically.

For instance, if a single nucleotide is added or removed, the reading frame is shifted, which can lead to completely different amino acids being incorporated downstream. Ultimately, frameshift mutations often result in nonfunctional proteins due to premature stop codons or entirely different sequences of amino acids, significantly affecting the organism's phenotype.

Other types of mutations, such as those that alter only one amino acid or occur in non-coding regions, do not have the same dramatic effect on the protein product or its expression. Additionally, certain mutations may indeed have no effect on a protein's function at all, which stands in contrast to the widespread implications of frameshift mutations.