Amber, ocher and opal mutations are specific types of nonsense mutations that result in production of protein chain terminating codons that prematurely stop protein synthesis during translation. Instead of the proper amino acid being inserted into the lengthening amino acid chain during protein synthesis, changes to the DNA code that result in amber, ocher, or opal nonsense mutations cause the synthesis of the protein to prematurely stop. Unless there is another mutation in a gene that codes for a transfer RNA (tRNA) that allows the suppression of a nonsense mutation, the premature termination of protein synthesis results in the manufacture and release of an incomplete and usually nonfunctional protein.

A change of a single nucleotide (point mutation) in a DNA molecule's polynucleotide strand results in an alteration of the sequence of three bases in the messenger ribonucleic acid (mRNA). This...