genetic code

The genetic code is the set of rules by which information encoded in genetic material (DNA or mRNA sequences) is translated into proteins (amino acid sequences) by living cells.

The code defines how sequences of three nucleotides, called codons, specify which amino acid will be added next during protein synthesis. A three-nucleotide codon in a nucleic acid sequence specifies a single amino acid.

Because the vast majority of genes are encoded with exactly the same code (see the RNA codon table), this particular code is often referred to as the canonical or standard genetic code, or simply the genetic code, though in fact some variant codes have evolved. For example, protein synthesis in human mitochondria relies on a genetic code that differs from the standard genetic code.