Description
All the information on your DNA is encoded by sequences of four different nucleotide bases: Adenine (A), cytosine (C), guanine (G), and thymine (T). These are called the genetic letters. Different combinations of these letters can be thought of genetic codes. These encode specific instructions, for example on how to build proteins. In RNA a different base, called uracil (U), is used instead of thymine, but these letters encode the same information.