CORVALLIS - Fifty years after James Watson and Francis Crick announced in the journal Nature that they had discovered the double helix structure of DNA, the photo that helped them unravel the mystery is finally getting its due recognition.
On Tuesday night (April 22), the PBS show NOVA debuts "Secret of Photo 51," which outlines the critical role that scientist Rosalind Franklin and her X-ray photo played in the discovery.
Franklin's original manuscript - and what appears to be the original "photo 51" - are in the Ava Helen and Linus Pauling Papers at Oregon State University. Pauling and other scientists were in a well-documented race with Watson and Crick to discover the structure of DNA. Before his death, Pauling donated all of his research papers and other materials to the university - more than 500,000 items.
How Pauling ended up with Franklin's originals is part fact and part conjecture, according to Cliff Mead, head of Special Collections at OSU. "A letter from Pauling to his son, Peter, an office mate of Crick and Watson, mentions that he may go to King's College in London to visit Franklin at her invitation," Mead said.
"After that, one has to speculate," he added. "Pauling had no good X-ray diffraction photos and he was probably hoping against hope that Watson and Crick had made a mistake. Our guess is that Franklin gave him both the manuscript and the photo at the time of his visit."
Several noted historians and scientists have looked at the Franklin manuscript and acknowledged its authenticity, Mead said. Franklin's crystallographic X-ray - photo 51 - is likely an original, too, he added.
"You can actually see the oxidization mark from the paper clip on the photo matching those same marks on the manuscript," Mead said.
According to a variety of accounts, including Watson's own memoirs, a colleague of Franklin's showed Watson and Crick the photo, not really understanding its significance at the time. Wrote Watson in his memoirs: "My mouth fell open and my pulse began to race." He could tell from one glance that the structure had to be a helix.
Watson and Crick immediately worked out the rest of the puzzle, using Franklin's photo as the key. That discovery led to the Nobel Prize in 1962, which they shared with another colleague. Franklin was not eligible for a share of the award, having died in 1958 at the age of 37 - never knowing the impact she had on science.
Hundreds of items from the Pauling Collection that help detail the discovery of the double helix - including Franklin's manuscript and famous photo - are available online through the OSU Special Collections website, "Linus Pauling and a Documentary History of DNA": http://osulibrary.orst.edu/specialcollections/dna. Find the search key and type in Rosalind Franklin.