On February 28, 1953, Francis Crick and James Watson, two unknown scientists, solved the secret to life. They had built a model for deoxyribonucleic acid (DNA). This model, a double helix, carries the genetic code -- the key molecule of heredity, developmental biology and evolution.
Watson had started out to become a naturalist. During his third year of study at the University of Chicago, he read a book by Erwin Schrodinger titled What is Life?. In this book, Schrodinger discusses the belief that one of life's essential features is the storage and transmission of information. In essence, a genetic code that passes from parent to child. This code has to be complex, yet compact enough to fit into a single cell. Watson was intrigued by his arguments and decided to switch his studies from birds to genetics.
While attending a conference in Naples, Italy, in 195l, he was further inspired by a speaker named Maurice Wilkins. Wilkins was using X-ray crystallography to understand the physical nature of DNA. These images suggested that DNA had a regular crystalline structure. Watson was excited by these images and felt that knowing what the structure was would lead to understanding how genes work.
During a fellowship at the Cavendish Laboratory in Cambridge, Watson met his partner Francis Crick. Crick had been a physicist who had switched to biology. He also had been impressed with Schrodinger's, What is Life. Because their interests were so similar, they spent many hours sharing their thoughts. They became determined to figure out what genes were and were convinced that understanding the structure of DNA would help them accomplish this.
Watson and Crick had examined the work of Linus Pauling. Pauling had figured out the structure of keratin, the protein that makes up hair and fingernails. It was a long corkscrew of atoms known as the alpha-helix. He had used X-ray crystallography for hints on the structure. Watson and Crick realized that Pauling understood the basic structure of DNA and was on the path to completely figuring it out. They knew they would have to imitate Pauling's work to beat him to the punch. What they really needed were x-rays of DNA. Since Cavendish's crystallographers were not working on DNA, they would have to look elsewhere.
Francis Crick contacted Maurice Wilkins (the man whose DNA images had originally inspired 's best diffraction pictures of DNA. Wilkins and Franklin did not like each other. Their strained relationship led Wilkins to declare publicly that one of her images suggested DNA had a helical shape. Franklin was furious. At this point, Wilkins and Franklin stopped talking. Their dislike for each other made it difficult for them to work together.
Watson and Crick took what they had learned and developed a theory that DNA was a triple helix. This theory was proven wrong and resulted in them being instructed to abandon their work on DNA. They turned over their research to Kings College and urged Franklin and Wilkins to continue their work.
Watson and Crick were assigned other projects to work on but their conversations always led back to the same subject - DNA. In December, 1952 they received information that indicated Linus Pauling would soon publish a paper on the structure of DNA. Watson examined the information and realized there was a mistake in Pauling's theory. He decided he would have to warn Franklin and Wilkins. A visit with Franklin turned sour after a heated discussion. Watson shared his unpleasant experience with Wilkins. During this conversation, Wilkins decided to show Watson one of Franklin's latest x-rays. Watson recalls, "The instant I saw the picture my mouth fell open." He knew that DNA must be a helix after all and he decided that two helical backbones made more sense than three. He was also excited to see that the pattern repeated itself every 34 angstroms (an angstrom is one ten-billionth of a meter). Further research led to more important clues. Several months later and several models later, it was announced that Watson and Crick had found the secret to life.
Rosalind Franklin died of cancer in l958, at the age of 37. She was never told the critical role her photography played.
In 1962, the Nobel Prize was awarded to Watson, Crick and Wilkins. Francis Crick believes that Rosalind Franklin would have been the recipient instead of Wilkins had she lived (the Nobel Prize is not given posthumously). Franklin's notebooks show she had narrowed the structure down to a double helix and her work had played a key role in solving the puzzle. In the end it was Watson who fit the final piece into the puzzle.Mendel
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