Guanine. Computer artwork of a molecule of guanine (2-amino-6-oxypurine). This is a purine- derived nucleic acid found in RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). The atoms shown as cylinders are colour coded: carbon (green), nitrogen (blue), hydrogen (white) and oxygen (red). Guanine is one of the four bases found in RNA (along with adenine, uracil and cytosine) and in DNA (with thymine, adenine, and cytosine). The positioning of these bases along the RNA and DNA chains is known as the genetic code. Each genetic code is unique and gives organisms their individual characteristics.