What occurs during a frameshift mutation?

During a frameshift mutation, nucleotides are inserted into or deleted from the DNA sequence in such a way that the reading frame is shifted. This alteration in the number of nucleotides changes the way the sequence is read during translation, which can lead to a completely different amino acid sequence downstream of the mutation.

The significance of this mutation lies in its potential to produce nonfunctional proteins or drastically altered protein products, as the original codon grouping is disrupted. Unlike point mutations, which typically change only one amino acid (or have no effect if the mutation is silent), frameshift mutations can result in a loss of function or introduce premature stop codons, leading to truncated proteins.

In summary, the key aspect of frameshift mutations is the insertion or deletion of nucleotides, which shifts the reading frame and often has profound effects on the resulting protein.