The Gene: An Intimate History - Siddhartha Mukherjee Page 0,68

by irreverence, zaniness, and fiery brilliance. They despised authority but craved its affirmation. They found the scientific establishment ridiculous and plodding, yet they knew how to insinuate themselves into it. They imagined themselves quintessential outsiders, yet felt most comfortable sitting in the inner quadrangles of Cambridge colleges. They were self-appointed jesters in a court of fools.

The one scientist they did revere, if begrudgingly, was Linus Pauling—the larger-than-life Caltech chemist who had recently announced that he had solved an important conundrum in the structure of proteins. Proteins are made of chains of amino acids. The chains fold in three-dimensional space to form substructures, which then fold into larger structures (imagine a chain that first coils into a spring and then a spring that further jumbles into a spherical or globular shape). Working with crystals, Pauling had found that proteins frequently folded into an archetypal substructure—a single helix coiled like a spring. Pauling had revealed his model at a meeting at Caltech with the dramatic flair of a sorcerer pulling a molecular bunny out of a hat: the model had been hidden behind a curtain until the end of the talk, and then—presto!—it had been revealed to a stunned, applauding audience. Rumor had it that Pauling had now turned his attention from proteins to the structure of DNA. Five thousand miles away, in Cambridge, Watson and Crick could almost feel Pauling breathing down their necks.

Pauling’s seminal paper on the protein helix was published in April 1951. Festooned with equations and numbers, it was intimidating to read, even for experts. But to Crick, who knew the mathematical formulas as intimately as anyone, Pauling had hidden his essential method behind the smoke-and-mirrors algebra. Crick told Watson that Pauling’s model was, in fact, the “product of common sense, not the result of complicated mathematical reasoning.” The real magic was imagination. “Equations occasionally crept into his argument, but in most cases words would have sufficed. . . . The alpha-helix had not been found by staring at X-ray pictures; the essential trick, instead, was to ask which atoms like to sit next to each other. In place of pencil and paper, the main working tools were a set of molecular models superficially resembling the toys of preschool children.”

Here, Watson and Crick took their most intuitive scientific leap. What if the solution to the structure of DNA could be achieved by the same “tricks” that Pauling had pulled? X-ray pictures would help, of course—but trying to determine structures of biological molecules using experimental methods, Crick argued, was absurdly laborious—“like trying to determine the structure of a piano by listening to the sound it made while being dropped down a flight of stairs.” But what if the structure of DNA was so simple—so elegant—that it could be deduced by “common sense,” by model building? What if a stick-and-stone assemblage could solve DNA?

Fifty miles away, at King’s College in London, Franklin had little interest in building models with toys. With her laserlike focus on experimental studies, she had been taking photograph after photograph of DNA—each with increasing clarity. The pictures would provide the answer, she reasoned; there was no need for guesswork. The experimental data would generate the models, not the other way around. Of the two forms of DNA—the “dry” crystalline form and a “wet” form—the wet form seemed to have a less convoluted structure. But when Wilkins proposed that they collaborate to solve the wet structure, she would have none of it. A collaboration, it seemed to her, was a thinly disguised capitulation. Randall was soon forced to intervene to formally separate them, like bickering children. Wilkins was to continue with the wet form, while Franklin was to concentrate on the dry form.

The separation hobbled both of them. Wilkins’s DNA preparations were of poor quality and wouldn’t generate good photographs. Franklin had pictures, but she found them difficult to interpret. (“How dare you interpret my data for me?” she once snapped at him.) Although they worked no more than a few hundred feet apart, the two of them might as well have inhabited two warring continents.

On November 21, 1951, Franklin gave a talk at King’s. Watson was invited to the talk by Wilkins. The gray afternoon was fouled by the soupy London fog. The room was an old, damp lecture hall buried in the innards of the college; it resembled a dreary accountant’s chamber in a Dickens novel. About fifteen people attended. Watson sat in the audience—“skinny and awkward . . . pop-eyed, and wrote down nothing.”

Franklin