What defines a frameshift mutation?

A frameshift mutation is specifically characterized by the insertion or deletion of one or more nucleotide bases in the DNA sequence, which alters the reading frame of the genetic code. This alteration shifts the way the nucleotides are grouped into codons, which are sequences of three bases that correspond to specific amino acids.

When the reading frame is changed, the entire sequence of amino acids following the mutation is likely affected, which can lead to dramatic changes in the resulting protein's structure and function. Unlike other types of mutations, such as substitutions or silent mutations, which might change one amino acid or have no effect at all, frameshift mutations often result in a completely different and typically nonfunctional protein.

The process of genetic translation relies on the correct reading frame to produce functional proteins, and any disruption caused by added or missing bases often leads to truncated proteins if a stop codon is reached prematurely. This is why understanding the nature of frameshift mutations is critical in genetics and molecular biology, as they can have serious implications for cellular function and organism health.