What type of mutation is caused by a change in a single nucleotide?

A mutation caused by a change in a single nucleotide is referred to as a point mutation. This type of mutation involves the substitution of one nucleotide base for another, which can result in changes to the amino acid sequence of a protein if it occurs within a coding region of DNA. Depending on the nature of the change, point mutations can lead to different outcomes:

1. Silent mutations, where the new nucleotide still codes for the same amino acid,

2. Missense mutations, where the new nucleotide results in a different amino acid, potentially altering the protein's function,

3. Nonsense mutations, where the substitution creates a premature stop codon, leading to a truncated protein.

In contrast, frameshift mutations arise when nucleotides are inserted or deleted from the DNA sequence, leading to a shift in the reading frame of the codons. Insertion and deletion mutations specifically refer to the addition or removal of nucleotides, which can have significant downstream effects due to the alteration of the reading frame. However, point mutations only involve a single nucleotide change, which is why the correct identification of this specific mutation type is important.