DNA Conceptual computer artwork of the double helix DNA deoxyribonucleic acid molecule lower centre a female face centre right and a DNA autoradiogram upper centre The strands of the DNA are linked by nucleotide bases horizontal bars the sequence of which forms a unique genetic code that controls the individual development and functioning of every living organism The sequence is obtained on autoradiograms as a sequence of bands white that represent the bases The four bases are adenine A thymine T guanine G and cytosine C labelled at lower centre