What type of mutation causes no change in the amino acid sequence?

A silent mutation is a change in the nucleotide sequence of a gene that does not result in a change in the amino acid sequence of the protein that is produced. This occurs because of the redundancy in the genetic code, where multiple codons can code for the same amino acid. For instance, if a silent mutation occurs in the third position of a codon, it may still code for the same amino acid due to the nature of how codons are paired with amino acids.

In contrast, a nonsense mutation introduces a premature stop codon, leading to shorter, nonfunctional proteins. A missense mutation changes one amino acid in the sequence, which can affect the protein's function. A frameshift mutation, caused by the insertion or deletion of nucleotides, alters the reading frame of the gene, often resulting in a completely different and usually dysfunctional protein. Thus, while these mutations affect the protein produced, a silent mutation maintains the amino acid sequence unchanged.