DNA sequence signalling the end of a gene
The genome of an organism contains millions of DNA bases. In this nearly endless sequence, only specific parts actually provide codes for proteins. Whenever the enzymes of a cell read and copy a gene in order to translate it into the corresponding protein, the enzymes must know where to start, and end, the transcription. For this purpose, the genome contains not only the DNA sequences which code for proteins, but also short sequences upstream and downstream of the coding sequence which signal the beginning and the end of the coding sequence. The signal for the end of a gene is called the terminator, or terminator sequence.