The Mysterious World of the Human Genome. Frank Ryan

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СКАЧАТЬ bacteria were allowed to go through their normal reproductive cycle, which allowed the viral cores inside them to generate entire new phage viruses, rupturing the bacterial bodies and flooding the growth media with large numbers of fully formed viruses. Hershey and Chase now removed what was left of the host bacterial bodies to gather dense concentrations of fully formed viruses.

      When they now compared the empty viral coats, made up of protein, with the fully formed viruses, with their cores full of genetic material, they found that 90 per cent of the radioactive sulphur was left behind in the viral coats when the virus infected the cell, and 85 per cent of the phosphorus was now part of DNA that had entered the bacterial cell to code for the future offspring of virus. This confirmed Avery’s findings: DNA, and not protein, was the code of heredity.

      We might duly note that this separation of coat from core DNA of virus involves a much higher degree of protein impurity than Avery’s extractions. Yet the hitherto sceptical geneticists appeared to be more convinced by the phage experiment than by Avery’s work. Perhaps the strikingly visual nature of the experiment was a factor. Perhaps it was the additional, quite different, avenue of confirmation. It didn’t harm credibility that leading geneticists were within the ‘phage camp’, too.

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      Today, with the advantage of retrospect, scientists by and large see the 1944 paper by Avery, MacLeod and McCarty as the pioneering discovery of DNA as the molecule of heredity. It has been portrayed as one of the most regrettable examples of a discovery that merited, but was not awarded, the Nobel Prize. There is ample evidence that Avery was recommended by senior colleagues, particularly within his own discipline of microbiology and immunology – indeed he was nominated twice, first in the late 1930s, for his work on the pneumococcal typing and its relevance to bacterial classification, and, after the 1944 paper was published, he was nominated yet again for his fundamental contribution to biology. But it would appear that the Nobel Committee was not sufficiently swayed. In retrospect, it is seen as a major omission that causes people to scratch their heads and wonder why.

      Dubos worked for fifteen years in the lab next door to Avery’s and, in so much as the reticent Professor allowed it, he had plenty of opportunity to get to know Avery and to understand his approach to science and his reaction to the stresses involved in pioneering new concepts. In Dubos’ opinion, writing in 1976, the curious lack of recognition most likely derived from a combination of happenstance and Avery’s own personality. He would subsequently remark how, in all that time, Avery never closed the door of his lab, or the small office that led off it, allowing any of his staff to come and talk to him. This same eternally open door also allowed Dubos to witness ‘Fess’s’ activities at the bench, to listen in to his conversations with colleagues and to observe his interludes of introspective brooding.

      This reserved, small and slender bachelor would inevitably arrive at work dressed in a neat and subdued style, his conservative attire somehow at one with the charm of his lively and affable behaviour. His eyes, under the domed bald head that seemed too voluminous for the frail body, were sparkling and always questioning, and he would transform the most ordinary conversation into an artistic performance with spirited gestures, mimicry, pithy remarks and verbal pyrotechnics. Avery might have been somewhat reticent in manner (he could be silently introspective), but in his own quintessential way he was vulnerably human, and that made him all the more interesting and enchanting.

      I would suggest that creativity in science is every bit as intertwined with personality as one finds in a writer, artist, or musically gifted composer or performer. It would seem unsurprising in an artist if he appeared unusually ascetic, withdrawn from the hurly-burly world of the surrounding New York, ensuring that he lived close enough to the Rockefeller Institute so he could walk to work. In his ways, Avery could seem curiously ambivalent. He suffered mood swings at times, when alone in the lab, when he would appear to be dejected by the difficulties facing him. Afterwards he would declaim, clearly referring to himself, that resentment hurts the person who resents much more than the person who is resented. He left many letters unanswered and refused to have a secretary. He refused to review, or sponsor, any scientific paper in which he had made no contribution. In Dubos’ words, ‘Graciousness and toughness when it came to what he himself was determined to do, was part of his nature.’ Avery was a very successful teacher during his early medical career, yet in his later years he appears to have resented being expected to lecture on his own research. In this respect, he bore some interesting similarities to Charles Darwin. Avery scrupulously avoided any discussion of his own health and any intrusion, however small, into his private life – which was devoted to his younger brother, Roy, and to an orphaned first cousin whom he supported all through his life. He never expressed resentment about criticisms of his work, even when these were unjustified. He left no record of his private thoughts, other than the letters to his brother. A single experience struck Dubos as being significant.

      One day, in early 1934, the same year that Avery suffered the onset of his thyrotoxicosis, Dubos told Avery that he was about to be married. The lady in question was a Frenchwoman living in New York, named Marie Louise Bonnet. Avery immediately rejoiced at the news. They were conversing in the laboratory on the sixth floor of the Rockefeller hospital building. During the subsequent animated conversation, Avery climbed out of his chair, walked to the window and looked out, as if lost for a moment in deep reflection. Returning to his chair, he mentioned that he had contemplated marriage years before, but that circumstances had not proved favourable to his plans. It seems likely that the lady in question was a nurse that Avery had met during the course he had taught to student nurses at the Hoagland Laboratory. Avery would have been about 32 years old at the time. For a moment or two the older man’s eyes were full of longing.

      ‘One of the great joys of life,’ he remarked to Dubos, ‘is to go home to someone who would rather see you than anybody else.’

      Fate would prove cruel to both men. Marie Louise Bonnet subsequently died from tuberculosis at a time when Dubos was pioneering the very antibiotics that would eventually help to cure the same illness. The marriage was childless and the effects of his wife’s death on Dubos were devastating. He resigned, forthwith, from his antibiotic researches, which were later taken up by his former teacher, Selman Waksman at Rutgers Agricultural College, now Rutgers University, and which led to the discovery of a series of important antibiotics, including streptomycin. This breakthrough resulted in Waksman being awarded the Nobel Prize in Medicine or Physiology in 1952.

      Much of what Dubos witnessed of Avery spoke of an intense focus and purity of purpose in science and his work. But, increasingly, his devotion to his research appeared to be accompanied by insularity bordering on reclusiveness.

      Scientists who have laboured long and hard at a difficult but eventually rewarding line of research are usually happy to talk about it – if not to the media or ordinary social channels, certainly to colleagues. They travel to scientific symposia. They take part in conferences. They enjoy the camaraderie that comes from sharing the same interests. In the words of Frank Portugal, ‘wide-ranging discussions with peers both individually and at meetings are part and parcel of the scientific process. It is an important component of how collaborations are formed and scientific advances are made and respected.’ Most scientists are only too glad to accept the, often rare, honours and distinction their work brings their way. Not so Oswald Avery.

      In 1944 Avery was proposed for an honorary degree at Cambridge University, a recognition most scientists would cherish. The following year he was awarded the Copley Medal by the Royal Society of London. Avery’s roots were English – in the late nineteenth century his family had emigrated to Canada from the city of Norwich – but he refused to visit England even on such prestigious occasions, putting forward the excuse that his state of health did not permit it except by travelling first class. In Dubos’ opinion, this was disingenuous, since the respective foundations would have funded the flights. That he might have felt nervous, claustrophobic, on the lengthy flight is possible. Recalling those dark moods in which Avery might mumble to himself about the damaging inflictions of resentment, it СКАЧАТЬ