This page is part of the GeneWarrior Documentation. Go to the main site of GeneWarrior

What is Translation?

See also how to translate DNA to protein.

Translation is the process where ribosomes create proteins by decoding nucleotide sequences. A single amino acid is encoded by three nucleotides (codon). The translation step from codon to amino acid (which codon encodes which amino acid) is determined by the genetic code (or translation table) that may slightly differ among different species.
Every nucleotide sequence can be translated in three different ways, depending on the starting position.
The first codon of the sequence GGGTTT can either be GGG, GGT or GTT, depending on whether the codon starts on position 1,2 or 3. These are called the three reading frames, and they result in three distinctly different protein sequences.

Translation starts with a specific initiation codon, commonly AUG (the start codon). Furthermore, translation is terminated by a stop codon.

Genetic Code (or Translation Table)

The genetic code is a set of rules on how a codon (three nucleotides) is translated to an amino acid. The default is the Standard code, which almost universal.
The genetic code can be depicted as a Codon Wheel (from Wikipedia):

The inner circle depicts the first nucleotide in the codon, the second ring the second nucleotide and the outermost ring the third nucleotide. U stands for Uridine, which is interchangeable with T (Thymidine).

However, depending on the phylogenetic clade there are some differences in the code, which mostly apply to start and stop codons.
For example, in the Genetic Code of the Mitochondrion, the TGA-codon encodes a tryptophan (W) instead of the stop codon in the standard genetic code.
To see the complete list of all currently known genetic codes, see NCBI's list.

Open reading frames (ORF)

An ORF is a DNA sequence which starts with a start codon and is not interrupted by stop codon until the last codon. An ORF is thus a candidate for a protein encoding gene.

For more information about the biological details of the translation process, see the well written and illustrated article from Nature.com.

See the Tutorial on how to translate DNA to protein.

Back to Documentation index