The Codon Table - DNA, RNA & the Codon Table Step by Step

The standard genetic code maps all 64 codons to amino acids or stops, and it is degenerate.

highlighted = computed this step

Every codon maps to one amino acid

The genetic code is a fixed lookup table: each of the 64 codons names one of 20 amino acids, or a stop signal. AUG, highlighted, names methionine.

\text{codon} \longrightarrow \text{amino acid}

The code is degenerate

Most amino acids are named by several codons, so the third base often does not change the amino acid — visible as solid colour blocks below. Honesty note: this is the standard genetic code; some organisms and mitochondria use minor variants, so it is standard, not universal.

\text{Ala} = \{\text{GCA},\text{GCC},\text{GCG},\text{GCU}\}

Start and stop

AUG also marks where translation starts. 3 codons — UAA, UAG, and UGA — name no amino acid and stop translation instead.

\text{AUG} \to \text{Met}, \quad \{\text{UAA},\text{UAG},\text{UGA}\} \to \text{stop}