Nonsense mutation: A mutation (a change) in a base in the DNA that prematurely stops the translation (reading) of messenger RNA (mRNA) resulting in a polypeptide chain that ends prematurely and a protein product that is truncated (abbreviated) and incomplete and usually nonfunctional.
The nonsense mutation converts a codon (a triplet of bases) that encodes an amino acid into a stop codon, one that specifies the termination of translation. There are three nonsense codons (UAG, UAA, and UGA) in mRNA. One of them comes normally at the end of each polypeptide. A nonsense codon is a stop codon which is out of place.
Catching such a defective messenger RNA (mRNA) before a truncated and potentially harmful protein is synthesized is the job of what is called the nonsense-mediated mRNA decay (NMD) pathway.
A mutation that changes a codon that codes for one amino acid into a codon that does not specify any amino acid (a nonsense codon).
Nonsense mutations. With a nonsense mutation, the new nucleotide changes a codon that specified an amino acid to one of the STOP codons (TAA, TAG, or TGA).
Nonsense mutation: A mutation (a change) in a base in the DNA that prematurely stops the translation (reading) of messenger RNA resulting in a polypeptide chain that ends ...
Brief and Straightforward Guide: What Is a Nonsense Mutation? ... We would love to know what you think! Please let us know if you have any comments or ...
In this example, the nucleotide cytosine is replaced by thymine in the DNA code, signaling the cell to shorten the protein.