Genetic code: Difference between revisions

Revision as of 09:42, 19 October 2003

Revision as of 19:54, 30 November 2003

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In classical genetics, the STOP codons were given names - UAG was amber, UGA was opal, and UAA was ocher. These names were originally the names of the specific genes in which mutation of each of these stop codons was first detected. Translation starts with a chain initiation or START codon, but unlike STOP codons these are not sufficient by themselves to begin the process; nearby initiation sequences are also required to induce transcription into mRNA and binding by [[ribosome]]s. The most notable ofstart thesecodon is AUG, which also codes for methionine. CUG and UUG, and in prokaryotes GUG and AUU, will also work.

It is notable that the standard genetic code contains features which provide for basic forms of [[error correction]]. Many codons which differ by only one base still encode the same amino acid and most often the single base that differs is the last one, which happens to be the base which is most often misread by the translation process. Furthermore, amino acids which tend to occur more frequently in proteins on average tend to have more codons which code for them.