How was DNA Discovered?

The identification of DNA and its structure is one of the most important discoveries of the twentieth century. The key individuals responsible for the discovery of the double helix structure of DNA were Francis Crick and James Watson. However, were it not for Rosalind Franklin, Linus Pauling and Maurice Wilkins, the two men would likely not have made the discovery following the crucial events that preceded their work.

In the Beginning

The story of DNA's discovery is actually quite an interesting one that began in the early 1950s, when Watson, a biologist, and Crick, a physicist, were working together in a laboratory in Cambridge, England. Their work focused on the structure of DNA. Pauling, a chemist, had discovered an important structure of protein in 1951 and Franklin was a chemist working busily in a laboratory in France at the time. Wilkins, a physicist from New Zealand, was a director for a biophysics laboratory at King's College. In 1951, he took the first x-ray pictures of DNA, which later resulted in his idea that DNA structure could be helical, similar to the protein structure shown by Pauling. After Watson arrived in England, he saw Wilkins' pictures of DNA and went to the Cavendish laboratory in Cambridge where he met Crick.

Working out the Correct Structure of DNA

Pauling had previously published a paper in 1953, where he proposed that DNA had a triple helical structure. In fact, Watson and Crick had similarly suggested a three helical model in 1951 but the theory ultimately proved incorrect. The mistake was actually somewhat based on a falsely recollected conversation that Watson had with Franklin, when Franklin had said that she used x-ray crystallography to establish the water content of DNA. Watson ended up incorrectly recalling the numbers.

The Importance of Photo-51

What finally sent Watson and Crick in the right direction was Franklin's photo-51. The picture itself showed DNA that had been crystallized and showed a blurred X in the centre of the molecule, revealing a helical structure. When Watson received a copy of photo-51, he saw the importance of the X in it. Watson and Crick then modelled the DNA structure as a two-chain helix, with the characteristic anti-parallel attributes and bases paired to stabilise the molecule. Shortly thereafter, their model of DNA was published.

Providing the Proper Credit

As with many discoveries, the question of who should justly receive credit can be a debatable one. Ultimately, it was the Watson and Crick paper that was published in the journal Nature in 1953, although directors at both the Cavendish and King's College laboratories had suggested to Nature that the paper by Watson and Crick as well as those by Wilkins and finally, Franklin and Gosling, be published in sequence. It was in 1962 that Crick, Watson and Wilkins received the Nobel Prize. Generally, however, when the topic of DNA discovery occurs, it is Watson and Crick who seem to be mentioned but it is important that others who contributed greatly to this important discovery receive recognition as well. Franklin's photo-51 in particular was a major aspect in facilitating the discovery of the DNA double helix. The discovery of DNA would eventually have a significant impact on science for years to come and still, today, remains a key area of research in the twenty-first century. Learn more about DNA structure.