Which of the following insertions or deletions would result in a frameshift mutation?

A frameshift mutation occurs when nucleotides are added or removed from the DNA sequence in a number that is not divisible by three, causing a shift in the reading frame of the codons during translation. This alteration affects how the sequence is read by ribosomes, resulting in a completely different sequence of amino acids downstream from the mutation site.

In this scenario, an insertion or deletion of one base pair would disrupt the triplet codon structure, shifting the reading frame and leading to a frameshift mutation. This wrong alignment in the sequence could potentially change every amino acid following the mutation.

In comparison, an insertion or deletion of two base pairs would also create a frameshift since it is not a multiple of three, but the question's focus on recognizing a singular, specific example means that inserting or deleting one base pair is a direct and clear instance of creating a frameshift.

An insertion or deletion of three base pairs would not result in a frameshift because it preserves the reading frame. The codons would still align correctly with sets of three nucleotides being read, resulting in the original downstream sequence remaining unchanged, except for the added or removed codon. Options involving four base pairs would similarly preserve the reading frame after the initial three are accounted