Definition of Codon

Codon: 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.