A mutation that converts a normal codon into a stop codon is referred to as what?

A mutation that converts a normal codon into a stop codon is called a nonsense mutation. This type of mutation leads to the premature termination of protein synthesis, resulting in a truncated protein that is most often nonfunctional. The significance of this lies in the fact that it can have profound effects on gene expression and the resultant phenotype, depending on the location of the mutation within the gene.

In contrast, a silent mutation does not alter the amino acid sequence of the protein, as it changes a codon to another that codes for the same amino acid. A missense mutation results in the substitution of one amino acid for another in a protein, which can affect protein function but does not lead to premature termination. A frameshift mutation involves the insertion or deletion of one or more nucleotides in the DNA sequence, which can shift the reading frame and change the entire amino acid sequence following the mutation, potentially leading to a nonsense mutation later on, but it is not specifically defined as converting a normal codon to a stop codon.