James Dewey Watson (1928 - present) shared the 1962 Nobel Prize in Physiology or Medicine with Francis Crick and Maurice Wilkins for their elucidation of the structure of deoxyribonucleic acid (DNA). In 1953, they determined the structure of DNA using X-ray diffraction. They found that the DNA molecule was shaped like a double helix and that the two chains of the helix unlinked like a zipper, so that each chain could create an identical copy of itself. Watson’s early research was on bacterial viruses and the fate of their DNA. Prior to solving the structure of DNA, he had determined the structure of the protein coat surrounding the tobacco mosaic virus. His later studies involved investigations into the structure of RNA and the general principles of virus construction.