Which type of mutation changes a single nucleotide but does not affect the amino acid created?

A silent mutation changes a single nucleotide in the DNA sequence without altering the resulting amino acid in the protein. This occurs because of the redundancy in the genetic code, where multiple codons can code for the same amino acid. For instance, if the DNA sequence changes from one codon to another that still codes for the same amino acid, the protein's structure and function remain unaffected.

In contrast, a missense mutation leads to a change in one amino acid in the protein, which can alter the protein’s function. A nonsense mutation introduces a premature stop codon, leading to incomplete and typically nonfunctional proteins. A frameshift mutation occurs when nucleotides are inserted or deleted from the DNA sequence, causing a shift in the reading frame and usually resulting in a completely different and nonfunctional protein. Therefore, a silent mutation is the only type of mutation listed that changes a nucleotide while preserving the identity of the amino acid sequence.