nonsense codon

ter·mi·na·tion co·don

trinucleotide sequence (UAA, UGA, or UAG) that specifies the end of translation or transcription. Compare: amber codon, ochre codon, umber codon.

Synonym(s): nonsense codon, punctuation codon, stop codon, termination sequence, termination signal

stop codon

Any of the 3 codons (or triplets of nucleotides—UAA, UAG and UGA) on an mRNA molecule which lack a cognate aminoacyl tRNA—i.e., do not code for an amino acid and thus signal the end of protein synthesis. When ribosomes hit a stop codon, mRNA transcription is terminated, causing polypeptide synthesis to stop and the ribosome to dissociate from the mRNA.

nonsense codon

One of the three nucleotide triplets (codons), UAG, UAA or UGA that mark an end point to a particular protein synthesis. U is the base uracil; A is the base adenine; and G is the base guanine.