- A set of any three adjacent bases in the DNA or RNA. There are 64 different codons of which 61 specify the incorporation of an amino acid into a polypeptide chain while the remaining three are stop codons that signal the end of a polypeptide. For example, the DNA codon ACG via its complementary RNA codon CGU specifies the amino acid arginine. For another example, the DNA codon TAC via its complementary RNA codon GUA specifies the amino acid valine. The three stop codons are UAA, UAG, and UGA. They are also called termination codons or nonsense codons. A = adenine; C = cytosine; G = guanine; U = uracil; T = thymine.
* * *A set of three consecutive nucleotides in a strand of DNA or RNA that provides the genetic information to code for a specific amino acid which will be incorporated into a protein chain or serve as a termination signal. SYN: triplet (3). [code + -on]- initiating c. the trinucleotide AUG (or sometimes GUG) that codes for the first amino acid in protein sequences, formylmethionine; the latter is often removed post-transcriptionally. SYN: start c..- initiation c. a specific mRNA sequence (usually AUG, but sometimes GUG) that is the signal for the addition of fMet-tRNA and the beginning of translation.- ochre c. the termination c. UAA.- opal c. SYN: umber c..- punctuation c. SYN: termination c..- start c. SYN: initiating c..- stop c. SYN: termination c..- termination c. trinucleotide sequence (UAA, UGA, or UAG) that specifies the end of translation or transcription. Cf.:amber c., ochre c., umber c.. SYN: nonsense c., punctuation c., stop c., termination sequence, termination signal.- umber c. the termination c. UGA. SYN: opal c..
* * *co·don 'kō-.dän n a specific sequence of three consecutive nucleotides that is part of the genetic code and that specifies a particular amino acid in a protein or starts or stops protein synthesis called also triplet
* * *n.the unit of the genetic code that determines the synthesis of one particular amino acid. Each codon consists of a section of the DNA molecule, and the order of the codons along the molecule determines the order of amino acids in each protein made in the cell.
* * *co·don (koґdon) a set of three adjacent bases on an mRNA that specifies an amino acid to be added to the growing polypeptide chain, or directs chain initiation or termination. Of the 64 different possible codons, 61 direct the incorporation of a specific amino acid into a polypeptide chain, with several of those also sometimes signaling chain initiation, and three signal chain termination (see table at genetic code, under code).
Medical dictionary. 2011.