In 1944, Avery, McCarty and McCloud established that genes (the basic functional units of heredity) are contained in molecules of deoxyribonucleic acid (DNA).

In 1954, Watson and Crick discovered the structure of DNA.

In 1958, Beadle and Tatum discovered that genes function in the production of enzymes and other proteins while studying the bread mold Neurospora crassa.  They proposed the "one-gene, one-protein" theory.

Since that time, DNA science has grown exponentially, splitting into subdisciplines such as molecular biology, recombinant DNA technology (biotechnology), genomics, proteomics and gene therapy.