The Mysterious World of the Human Genome. Frank Ryan

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      Maurice had had a natural scientific curiosity even as a boy, and it was this curiosity that led to his studying physics as part of his BA at Cambridge University, after which he worked for his PhD under John Turton Randall (later knighted), a physicist who played a leading role in the development of radar during the war.

      As a postgraduate, Wilkins moved to the University of Birmingham, following the posting of his Cambridge tutor, Randall, where the two scientists continued their collaboration on radar. But then, out of the blue, Wilkins found himself dispatched to the United States to work on the Manhattan Project. His purpose was to figure out how to purify suitable isotopes of uranium from impure sources, to make them suitable for the atomic bomb. In February 1944 Wilkins crossed the dangerous waters of the Atlantic on the Queen Elizabeth, heading for the University of Berkeley, California. Here he made a modest contribution to the development of the atomic bomb. However, the subsequent destruction of Hiroshima and Nagasaki by the very weapons that he had worked on left Wilkins somewhat unsettled in conscience.

      After the war Wilkins returned to England, where he ended up as assistant director of the new Biophysics Unit at King’s College London, funded by the Medical Research Council, and where his former boss, Randall, was now the Wheatstone Professor of Physics. The new departmental remit was to apply the experimental methods of physics to important biological problems. This would result in Wilkins developing a relationship with Watson and Crick and joining the search for the molecular code of DNA. It would also involve him in a somewhat infamous strained working relationship with the X-ray crystallographer Rosalind Franklin.

      Given this developing history, we might pause a moment or two to consider Wilkins’ personality, and its relevance to the com-ing storm. From what one can gather from his belatedly published biography, and the memory of those who knew him and worked with him, Wilkins was a quiet, highly moral man, somewhat Quaker-like in social attitudes. As a boy he enjoyed a close emotional relationship with his elder sister, Eithne, who taught him to dance. But this intimacy was torn apart when Eithne developed a bacterial infection that turned into a septicaemia, the blood-borne infection provoking septic arthritis in multiple joints. This would have been a shockingly painful and disabling condition, which, prior to antibiotics, might have proved fatal. She spent months in a hospital bed, with her limbs dangling from hoists, her joints lanced open to drain the pus. The unfortunate Eithne survived but the intimacy with her younger brother ended. The trauma of this experience may well have affected his self-confidence, particularly in his relationships with women.

      While an undergraduate at Cambridge, he fell in love with a woman called Margaret Ramsey, but he ‘was incapable of making a suitable advance to her’. After he told her of his love, there was a short silence after which she walked from the room. During his stay in Berkeley, Wilkins was attracted to an artist named Ruth, who had shared lodgings with him. She conceived a child and they subsequently married, but when, as the war was ending, he informed Ruth that he intended to return to the UK, she refused to accompany him. ‘Ruth told me one day that she had made an appointment for me with a lawyer and when I arrived at his office I was shocked to hear that Ruth wanted to end our marriage.’ Shortly after the divorce, Ruth gave birth to a son. Wilkins went to see her, and their baby, in the hospital ward, before returning to the UK alone.

      Wilkins would admit to difficulty overcoming an innate shyness, and he would require periodic psychotherapy in his time working at King’s, but he subsequently found a wife, Patricia, who appreciated the sensitive soul behind the diffident exterior, and he enjoyed a happy marriage and the joys of rearing a family of four children. There was also a fruitful outcome of his unsettled conscience following his work on the Manhattan Project. Before leaving Berkeley, one of his working colleagues came to his rescue … ‘Seeing I wanted to find some new direction, he lent me a new book with the rather ambitious title, What Is Life?’

       four

       A Couple of Misfits

       Francis likes to talk … He doesn’t stop unless he gets tired or he thinks the idea’s no good. And since we hoped to solve the structure by talking our way through it, Francis was the ideal person to do it.

      JAMES WATSON

      It is somewhat ironic that Maurice Wilkins only arrived in Naples by happenstance, since he was substituting for Randall, who had agreed to present the talk but had been unable to attend. It seems unlikely, had Randall himself presented the lecture, that he would have included the DNA slide, or that he would have spoken of what it portrayed with such clear reference to Schrödinger’s book. This lecture, which so excited Watson, was on the physico-chemical structure of big biological molecules, mostly proteins, made up of thousands of atoms. The key photograph had been taken by Wilkins, working together with a graduate student called Raymond Gosling while using a technique called X-ray diffraction. One of the things this technique was particularly good at was finding the sort of repetitive molecular themes you found in crystals, hence the other term for it: X-ray crystallography.

      ‘Suddenly,’ as Watson would later recall, ‘I was excited about chemistry.’

      Up to this moment Watson had had no idea that genes could crystallise. To crystallise, substances must have a regular atomic structure – a lattice-like structure of atoms at the ultramicroscopic level. The youthful Watson appears to have been a wonderfully free spirit journeying from one interesting encounter to another. Impulsive, impatient, egregiously direct, yet all the while on the hunt for new adventure.

      ‘Immediately I began to wonder whether it would be possible for me to join Wilkins in working on DNA.’ But Watson never got to work with Wilkins. Instead, happenstance headed him in the direction of another X-ray crystallographer called Max Perutz, who was working at the Cavendish Laboratory at Cambridge University.

      The Cavendish Laboratory is a world-famous department of physics. First established in the late nineteenth century to celebrate the work of British chemist and physicist Henry Cavendish, one of its founders and the first Cavendish Professor of Physics was James Clerk Maxwell, famous for his development of electromagnetic theory. The fifth Cavendish Professor and the director of the laboratory at the time of Watson’s arrival was William Lawrence Bragg, who was the successor, as director, to Lord Ernest Rutherford, another Nobel Prize-winner and the first physicist to split the atom. Bragg was an Australian-born physicist who, jointly with his father, had been awarded the Nobel Prize in Physics in 1915 for establishing the use of X-rays in analysing the physico-chemical structures of crystals. X-ray beams are bent when they pass through the orderly atomic lattice of crystals. What is projected onto the photographic plate is not the picture of the atoms within the structure but the refracted pathways of the X-rays after they have collided with the atoms. This is called ‘diffraction’ and is similar to how light is bent when it passes through water. In a structure with haphazard positioning of atoms in space, the X-rays will be scattered randomly and form no pattern. But in a structure that contains atoms in a repetitive atomic lattice – such as a crystal – the X-rays are deflected in a recognisable pattern of blobs on the X-ray plate. From this diffraction pattern, the atomic structure of the structure can be deduced.

      The two Braggs – father and son working as a team at the University of Leeds – had constructed the first X-ray spectrometer, allowing scientists to study the atomic structure of crystals. At the age of 22, Bragg Junior, now a Fellow of Trinity at Cambridge, had produced a mathematical system, Bragg’s Law, that enabled physicists to calculate the positions of the atoms within a crystal from the X-ray diffraction pictures. At the time of Watson’s arrival into the laboratory, Bragg’s main focus СКАЧАТЬ