The genetic code is the set of rules by which information encoded in DNA and RNA is translated into proteins. There are 64 possible three-letter codons (4³ = 64), but only 20 standard amino acids — so most amino acids are encoded by more than one codon. Three codons (UAA, UAG, UGA) signal "stop here": they terminate protein synthesis. One codon (AUG) does double duty: it encodes methionine and serves as the universal start signal for protein synthesis.
Click any codon in the table below to see full details. Use the filters to highlight amino acids by chemical category.
Table uses RNA codon notation (U instead of T). The table reads: first base (rows) × second base (column groups) × third base (columns within group).