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James Watson and Francis Crick and the original DNA modelThe discovery of the molecular structure of DNA by James Watson and Francis Crick in 1953 is often considered to be revolutionary and is regarded as one of the greatest scientific breakthroughs in the twentieth century. The structure, as it is often claimed, revealed “the secret of life”, since it provided an explanation of how genetic material was encoded and copied. In historical accounts the achievement is often linked to the beginning of the “biotechnological revolution” and the foundation of molecular biology as a new scientific discipline. In this essay I am going to examine the photograph taken by Antony Barrington Brown, a former chemist student who worked as a photographer in Cambridge. The image was the first picture to depict Francis Crick and James Watson with their model of DNA double helix. Despite the fact that it was taken in May 1953, soon after the elucidation of DNA structure, the image first appeared in print fifteen years later, in James Watson’s account of their discovery, The Double Helix. After it was published, the photograph became increasingly popular in the media and became regarded as an ‘icon of scientific discovery’. (Iconic Photos, 2012) The purpose of this essay is to investigate the story behind the image and examine the historical and social contexts of the scientific discovery and its implications.
Watson, Crick and their model, 21 May 1953. Courtesy of Antony Barrington Brown. The photograph shows Francis Crick (on the right) and James Watson (on the left), with the former ‘pointing up to the model with a slide- rule’ and the latter ‘following Crick's movement with an innocent and amazed gaze’. (de Chadarevian, 2002, p. 238) So, what is the story behind this image? Despite the fact that the model depicted on the photograph is generally referred to as the ‘original model’, Francis Crick later recalled that there was a number of earlier models. (de Chadarevian, 2002) The fate of the ‘original’ model is unknown, however; Soraya de Chadarevian states in Designs for life that ‘once transported from the Cavendish Laboratory to the LBM, the model apparently became neglected’ and that ‘parts of it broke off and many pieces disappeared’. (de Chadarevian, 2002, p. 237) It is interesting to investigate the story of the photograph, which, it can be even said, was taken almost by accident. As Antony Barrington Brown himself later recalled, back in 1953 he was contacted by a friend, who became interested in Watson and Crick’s work and wanted to write an article about the scientists. Therefore, he asked the photographer to take a picture of the model. Barrington Brown, however, was not impressed by the model and did not find it photogenic: “Although supposedly a chemist myself it meant absolutely nothing to me and fortunately they did not expose my ignorance by attempting to explain it in terms I might just have comprehended.” (Iconic Photos, 2012) Therefore, he decided to stage the scientists in front of the model: “I set up my lights and camera and said “you’d better stand by it and look portentous” which they lamentably failed to do, treating my efforts as a bit of a joke.” (Iconic Photos, 2012) Barrington Brown took four photographs of Watson and Crick with the model and also another four of the scientists drinking coffee. The pictures were offered to Time magazine, which, however, refused to publish them. Since 1968, when one of the photographs, the one this essay is dedicated to, was published, it has become greatly popularized by the media.
James Watson and Francis Crick. Courtesy of Antony Barrington Brown. 1953 In this part of my essay I would like to examine the historical context of Watson and Crick’s achievement. First of all, how did biology progress from Gregor Mendel’s laws of inheritance to the discovery of DNA structure? DNA was first isolated by Friedrich Miescher in the second half of the nineteenth century; however it was not until 1940s when DNA began to be seen as the carrier of the genetic information, most notably after the Avery–MacLeod–McCarty and the Hershey-Chase experiments. (Ede, Cormack, 2012) Before that, DNA did not capture scientists’ interest because of its ‘apparent monotonous structure’, and was seen as ‘a poor candidate for the miraculous capabilities of the gene’. (Sarkar, 2001, pp. 16-17) What is more, it was widely believed that proteins encoded the genetic material, since, unlike DNA, they were known to have a complex structure. (Sarkar, 2001) What historical factors influenced the discovery of DNA structure and function in 1953? Firstly, there was a widespread opinion that science played a crucial part in the Second World War and had a direct influence on the course of the war, particularly because of such scientific achievements as radar and penicillin. (de Chadarevian, 2002) This belief increased public’s trust in science and encouraged governments’ support. Furthermore, According to Jon Agar, scientists became interest in DNA in part because of the ‘proliferation of information technologies’ and ‘the high status attached to them during the Cold War’, a historical phenomenon that in turn ‘encouraged talk of “information” and “codes”’. (Agar, 2012, p. 387) Apart from that, it is interesting to point out that many scientists, who were involved in DNA research, including Francis Crick, were previously physicists. It has been suggested that this shift to biology was partly influenced, by their ‘desire to turn from the sciences of death to the sciences of life’. (Agar, 2012, p. 389) Thus, physics, most notably, x-rays and radioactive tracers, played an important role in the discovery of DNA structure: ‘using many of the resources and techniques from the physics lab, genetics and cell biology gained momentum in the aftermath of World War II’. (Ede, Cormack, 2012, p. 334) In this section I am going to give a brief outline of the history of the discovery of DNA double helical structure by James Watson, an American biologist, and Francis Crick, a British biophysicist. To begin with, the Cavendish Laboratory at Cambridge University, where Watson and Crick worked, was not the only research center that was concerned with solving DNA structure. Other scientists involved in DNA research include, most notably, Linus Pauling, an American biochemist based in California, and Maurice Wilkins, a physicist, previously involved in the Manhattan Project, who worked with Rosalind Franklin, an x-ray crystallographer, at King’s College London. It is generally acknowledged that it was Rosalind Franklin’s famous x-ray diffraction photograph of DNA, commonly known as ‘Photo 51’, that played a crucial role in revealing the structure of the molecule to Watson and Crick. (Ede, Cormack, 2012) In April, 1953 James Watson and Francis Crick published an article in Nature, where they first described the findings of their research and gave a description of the discovery. In the article the scientists mention the three-chain structure of the molecule proposed by Linus Pauling and Robert Corey, which they considered to be ‘unsatisfactory’ for a number of reasons. (Watson, Crick, 1953) According to Watson and Crick’s model, the molecule consisted of two antiparallel helical chains. It had already been established before that DNA was chemically composed of four kinds of bases, a deoxyribose (a particular type of sugar) and a phosphate group. The scientists used these already known facts and managed to explain how the structure of the molecule was organized. Watson and Crick describe their ‘radically different’ double helical structure, paying considerable attention to explaining the base pairing mechanism, according to which ‘only specific pairs of bases can bond together’. (Watson, Crick, 1953, p. 737) This ‘novel feature’ of the structure became later known as the principle of ‘complementarity’. What is interesting to point out is that Watson and Crick do not state explicitly but rather hint that DNA could be the carrier of the genetic information: ‘It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material’. (Watson, Crick 1953, p. 737) In 1962, James Watson, Francis Crick and Maurice Wilkins were awarded the Nobel Prize in Physiology or Medicine “for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material”. (Nobel Prize Web Site) So, how did James Watson and Francis Crick manage to solve the puzzle and win the ‘race for double helix’? There are a number of opinions on this matter. For instance, as John Kendrew, a British biochemist, pointed out, their success was due to the synthesis of two research centers, the American, concerned with information, represented by James Watson, and the British ‘structural school’, one of the followers of which was Francis Crick. According to Kendrew, the close connection between these schools was established in Watson and Crick’s collaboration. (De Chadarevian, 2002, p. 166) Both the scientists later attributed their achievement to the favorable relationship that existed between them, which allowed them to complement and encourage each other and proved to be ideal for scientific collaboration. (Magner, 2002) However, Watson and Crick, whose methods included a combination of guessing, model building based on the research conducted by other scientists in x-ray crystallography, were later criticized particularly for the ‘unacknowledged exploitation’ of Rosalind Franklin’s x-ray diffraction photographs, which were shown to Watson and Crick by Maurice Wilkins without her approval. (Magner, 2002 p. 381) Despite the fact that the scientists did mention Franklin’s name in their article published in Nature in 1953, they did not state explicitly the significance of her contribution to the discovery. Going back to the photograph, why was it neglected by Time magazine in 1953? Why was it only published 15 years later? To answer these questions it is essential to examine how the discovery of DNA double helix was received in that period and how that changed with time. First of all, according to a number of historians of science, it is important to understand that in 1953 this achievement did not play the role it did in the later historical accounts. While in modern society it is seen as one of the most significant achievements of science in the twentieth century, back in 1953 the discovery, as Francis Crick himself later stated in an interview, ‘was not regarded, the way it is nowadays, as an overwhelming breakthrough’. (de Chadarevian, 2002, p. 243). There are several reasons for this. For instance, Jon Agar argues that ‘the relationship between DNA, as the chemical of genes, and the cells and bodies it affected needed to be worked out, which took time’. (Agar, 2012, p. 391) According to him, the significance of the discovery was recognized two decades later, with the invention of genetic engineering and the emergence of biotechnology, which increased the public interest in molecular biology and would ‘retrospectively brighten the light of Watson and Crick’s discovery.’ (Agar, 2012, p. 391) Furthermore, de Chadarevian also claims that the discovery started to increase in importance in later historical accounts, where it began to be seen as the starting point of molecular biology. Molecular biology was a new science established in the twentieth century, it became an independent discipline in 1950s after its separations from biophysics. Today, despite a number of earlier significant achievements, it is Watson and Crick’s discovery that is generally considered to be the foundation of the science. However, it took time for historians to recognize its significance for the field; De Chadarevian states that ‘in the disputes on the origins of molecular biology fought out between participants in the late 1960s, the double helix acquired its central role’. (De Chadarevian, p. 245) As I have already mentioned, the iconic photograph appeared in print for the first time in Watson’s The Double Helix, fifteen years later after it was taken by Barrington Brown. The book became successful since it was a first-person account, which was not a typical case at that time, and is believed to have popularized the discovery. Watson uses ‘techniques of the thriller, the detective story and the gossip column’ to describe the events. (Hayes, 2012, p 66) What is more, it gave an insight into the life of scientists, provided a new perspective on how science was done; according to Watson’s account, science was a competition, a race. Watson account depicted their discovery as a heroic achievement, and the story of the “race for the double helix” began to gain significance both in scientific circles and in public opinion. Thus, the fate of the photograph reflects the story of Watson and Crick’s discovery. Just as the discovery was underestimated and not paid considerable attention to, the photograph was neglected and remained unpublished for fifteen years. To sum up, in this essay I have provided a historical context of the discovery of the molecular structure of DNA, illustrating how certain factors, such as the Second World War and the Cold War, influenced the forming field of molecular biology. Having examined the historical and social contexts I have shown that the interest in the discovery began to rise in the late 1960s and 1970s due to a number of reasons. In particular, the invention of the genetic engineering and the potential of biotechnology in such fields as medicine and agriculture revealed the significance of the discovery, without which these scientific advances would have been impossible. The achievement also became seen as a scientific breakthrough in later historical accounts, where it began to be regarded as the event that laid the foundations of molecular biology. Finally, the discovery was also greatly popularized by James Watson himself in his personal account The Double Helix. The photograph that was published with the book perfectly reflected the idea a “heroic discovery” and Watson’s depiction of science as a race. Word Count: 2282 Bibliography:
Date: 2016-01-03; view: 1571
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