What characterizes a non-sense mutation?

A non-sense mutation is characterized by the introduction of a premature stop codon in the coding sequence of a gene. This early termination of translation leads to the production of a truncated protein, which is typically nonfunctional. The occurrence of a stop codon disrupts the normal flow of genetic information by halting the synthesis of the protein before the entire coding sequence has been translated. This can have significant consequences for the organism, as it may result in a completely inactive protein or a protein that is missing critical functional domains.

The other choices illustrate different types of mutations. A mutation that does not change any amino acids generally refers to a silent mutation, where the altered codon still codes for the same amino acid due to the redundancy of the genetic code. A mutation that leads to the same amino acid being formed also pertains to silent or synonymous mutations. Conversely, a mutation that alters the reading frame describes a frameshift mutation, where insertions or deletions of nucleotides shift the grouping of codons, potentially resulting in a completely different amino acid sequence downstream without necessarily introducing a premature stop codon.