Rosalind Franklin, to help solve the structure. Unfortunately Rosalind and Maurice found it difficult to work together. He wanted her to pay more attention to the wetter form (the so-called B form), which gave a simpler X-ray pattern but a more revealing one than that given by the slightly drier form (the A form), though the latter gave more detailed X-ray pictures.
At Cambridge I was working on a Ph.D. thesis about the X-ray diffraction of proteins. Jim Watson, a visiting American, then age twenty-three, was determined to discover what genes were and hoped that solving the structure of DNA might help. We urged the London workers to build models, using the approach Linus Pauling had used to solve the α helix. We ourselves produced a totally incorrect model, as did Linus Pauling a little later. Finally, after many ups and downs, Jim and I guessed the correct structure, using some of the experimental data of the London group together with Chargaff’s rules about the relative amounts of the four bases in different sorts of DNA.
I first heard of Jim from Odile. One day when I came home she said to me, “Max was here with a young American he wanted you to meet and—you know what—he had no hair!” By this she meant that Jim had a crew cut, then a novelty in Cambridge. As time went on Jim’s hair got longer and longer, as he tried to take on the local coloration, though he never got so far as to sport the long hair that men wore in the sixties.
Jim and I hit it off immediately, partly because our interests were astonishingly similar and partly, I suspect, because a certain youthful arrogance, a ruthlessness, and an impatience with sloppy thinking came naturally to both of us. Jim was distinctly more outspoken than I was, but our thought processes were fairly similar. What was different was our background knowledge. By that time I knew a fair amount about proteins and X-ray diffraction. Jim knew much less about these topics but a lot more about the experimental work on phages (bacterial viruses) and especially those associated with the Phage Group, led by Max Delbrück, Salva Luria, and Al Hershey. Jim also knew more about bacterial genetics. I suspect our knowledge of classical genetics was about the same.
Not surprisingly, we spent a lot of time talking over problems together. This did not pass unnoticed. Our group at the Cavendish had started with very little—for a brief period in 1949 we all worked in one room. By the time Jim joined us, Max and John Kendrew had a tiny private office. At this point the group was offered an extra room. It was not clear at first who should have this till one day Max and John, rubbing their hands together, announced that they were going to give it to Jim and me, “… so that you can talk to each other without disturbing the rest of us,” they said. A fortunate decision, as it turned out.
When we met Jim had already obtained his doctorate, whereas I, though some twelve years older, was still a graduate student. Maurice Wilkins, in London, had done much of the initial X-ray work, which was then taken over and extended by Rosalind Franklin. Jim and I never did any experimental work on DNA, though we talked endlessly about the problem. Following Pauling’s example, we believed the way to solve the structure was to build models. The London workers followed a more painstaking approach.
Our first attempt at a model was a fiasco, because I thought, quite erroneously, that the structure contained very little water. This mistake was partly due to ignorance on my part—I should have realized that a sodium ion was likely to be heavily hydrated—and partly due to Jim’s misunderstanding of a technical crystallographic term that Rosalind had used in a seminar she gave. [He mixed up “asymmetric unit” and “unit cell.”]
This was not our only mistake. Misled by the term tautomeric forms, I assumed that certain hydrogen atoms on the periphery of the bases could be in one of several
At Cambridge I was working on a Ph.D. thesis about the X-ray diffraction of proteins. Jim Watson, a visiting American, then age twenty-three, was determined to discover what genes were and hoped that solving the structure of DNA might help. We urged the London workers to build models, using the approach Linus Pauling had used to solve the α helix. We ourselves produced a totally incorrect model, as did Linus Pauling a little later. Finally, after many ups and downs, Jim and I guessed the correct structure, using some of the experimental data of the London group together with Chargaff’s rules about the relative amounts of the four bases in different sorts of DNA.
I first heard of Jim from Odile. One day when I came home she said to me, “Max was here with a young American he wanted you to meet and—you know what—he had no hair!” By this she meant that Jim had a crew cut, then a novelty in Cambridge. As time went on Jim’s hair got longer and longer, as he tried to take on the local coloration, though he never got so far as to sport the long hair that men wore in the sixties.
Jim and I hit it off immediately, partly because our interests were astonishingly similar and partly, I suspect, because a certain youthful arrogance, a ruthlessness, and an impatience with sloppy thinking came naturally to both of us. Jim was distinctly more outspoken than I was, but our thought processes were fairly similar. What was different was our background knowledge. By that time I knew a fair amount about proteins and X-ray diffraction. Jim knew much less about these topics but a lot more about the experimental work on phages (bacterial viruses) and especially those associated with the Phage Group, led by Max Delbrück, Salva Luria, and Al Hershey. Jim also knew more about bacterial genetics. I suspect our knowledge of classical genetics was about the same.
Not surprisingly, we spent a lot of time talking over problems together. This did not pass unnoticed. Our group at the Cavendish had started with very little—for a brief period in 1949 we all worked in one room. By the time Jim joined us, Max and John Kendrew had a tiny private office. At this point the group was offered an extra room. It was not clear at first who should have this till one day Max and John, rubbing their hands together, announced that they were going to give it to Jim and me, “… so that you can talk to each other without disturbing the rest of us,” they said. A fortunate decision, as it turned out.
When we met Jim had already obtained his doctorate, whereas I, though some twelve years older, was still a graduate student. Maurice Wilkins, in London, had done much of the initial X-ray work, which was then taken over and extended by Rosalind Franklin. Jim and I never did any experimental work on DNA, though we talked endlessly about the problem. Following Pauling’s example, we believed the way to solve the structure was to build models. The London workers followed a more painstaking approach.
Our first attempt at a model was a fiasco, because I thought, quite erroneously, that the structure contained very little water. This mistake was partly due to ignorance on my part—I should have realized that a sodium ion was likely to be heavily hydrated—and partly due to Jim’s misunderstanding of a technical crystallographic term that Rosalind had used in a seminar she gave. [He mixed up “asymmetric unit” and “unit cell.”]
This was not our only mistake. Misled by the term tautomeric forms, I assumed that certain hydrogen atoms on the periphery of the bases could be in one of several
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