Double stranded DNA with 600 base pairs coloured by element, visualized in UCSF ChimeraX software. DNA (deoxyribonucleic acid) is the genetic material which enables heredity in organisms. It is composed of four nucleotides G, C, A and T, triplets of which code for one amino acid at a time to produce proteins during cellular transcription. The double helical structure of DNA was discovered by Watson and Crick in the early 1950s.