Stop codon

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A stop codon is special sequence in the genetic code. It is a nucleotide triplet in messenger RNA that signals the end of translation.

It is a codon (that is, a sequence of three nucleotides in messenger RNA). It indicates the end of a gene. Similar to how a full stop indicates the end of a sentence, a stop codon signals the end of genetic translation.[1]

They are also called termination codons or chain termination codons. There are three such codons: UAA, UAG and UGA.

Proteins are based on polypeptides, which are unique sequences of amino acids. Most codons in messenger RNA correspond to the addition of an amino acid to a growing polypeptide chain, which may ultimately become a protein. Stop codons indicate the end of this process, and therefore, the end of polypeptide synthesis.

References[change | change source]

  1. Griffiths A.J.F. et al (2000). "Chapter 10 (molecular biology of gene function): Genetic code: stop codons". An introduction to genetic analysis. W.H. Freeman (go to end of excerpt). http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=iga.section.1845#1872.