What is the consequence of a frameshift mutation?

A frameshift mutation occurs when nucleotides are added or deleted from the DNA sequence, and the number of nucleotides affected is not a multiple of three. This alteration causes a shift in the way the sequence is read during translation. The codons, which are groups of three nucleotides, determine which amino acids are added to the growing polypeptide chain. When the reading frame shifts, the entire downstream sequence is changed, resulting in the incorporation of incorrect amino acids and ultimately leading to the production of a non-functional protein or a protein that behaves differently than intended.

This shift can result in significant changes to the protein's structure and function, often leading to a complete loss of function. In some cases, the frameshift mutation might also create a premature stop codon, truncating the protein and further preventing it from functioning properly.

Thus, the alteration of the reading frame is the fundamental outcome of a frameshift mutation, directly impacting protein synthesis and function.