James Watson & Francis Crick on Feb. 28, 1953, Francis Crick walked into the Eagle pub in Cambridge, England, and, as James Watson later recalled,announced that “we had found the secret of life.” Actually, they had. That morning, Watson and Crick had figured out the structure of deoxyribonucleic acid, DNA. And that structure – a “double helix” that can “unzip” to make copies of itself – confirmed suspicions that DNA carries life’s hereditary information. Not until decades later, in the age of genetic engineering, would the Promethean power unleashed that day become vivid. But from the beginning, the Watson and Crick story had traces of hubris. As told in Watson’s classic memoir, “The Double Helix,” it was a tale of boundless ambition, impatience with authority and disdain, if not contempt, for received opinion. (“A goodly number of scientists,” Watson explained, “are not only narrow-minded and dull but also just stupid.”) Yet the Watson and Crick story is also one of sublime harmony, an example, as a colleague put it, of “that marvelous resonance between two minds – that high state in which 1 plus 1 does not equal 2 but more like 10.”
The men were in some ways an odd pair. The British Crick, at 35, still had no Ph.D. The American Watson, 12 years Crick’s junior, had graduated from the University of Chicago at 19 and nabbed his doctorate at 22. But they shared a certain wanderlust, an indifference to boundaries. Crick had migrated from physics into chemistry and biology, fascinated by the line “between the living and the nonliving.” Watson had studied ornithology, then forsook birds for viruses, and then, doing postdoctoral work in Europe, took another sharp career turn.
At a conference in Naples, Watson saw a vague, ghostly image of a DNA molecule rendered by X-ray crystallography. DNA, he had heard, might be the stuff genes are made of. “A potential key to the secret of life was impossible to push out of my mind,” he later wrote. “It was certainly better to imagine myself becoming famous than maturing into a stifled academic who had never risked a thought.”
This theme of Watson’s book – the hot pursuit of glory, the race against the chemist Linus Pauling for the Nobel Prize that DNA would surely bring–got bad reviews from the (relatively) genteel Crick. He didn’t recall anyone mentioning a Nobel Prize. “My impression was that we were just, you know, mad keen to solve the problem,” he later said. But whatever their aims, Watson and Crick shared an attraction to DNA, and when they wound up in the same University of Cambridge lab, they bonded.
Fatefully, such amity did not prevail at a laboratory over at King’s College, London, where a woman named Rosalind Franklin was creating the world’s best X-ray diffraction pictures of DNA. Maurice Wilkins, a colleague who was also working on DNA, disliked the precociously feminist Franklin, and the feeling was mutual. By Watson’s account, this estrangement led Wilkins to show Watson one of Franklin’s best pictures yet, which hadn’t been published. “The instant I saw the picture my mouth fell open,” Watson recalled. The sneak preview “gave several of the vital helical parameters.”
Franklin died of cancer in 1958, at 37. In 1962 the Nobel Prize, which isn’t given posthumously, went to Watson, Crick and Wilkins. In Crick’s view, if Franklin had lived, “it would have been impossible to give the prize to Maurice and not to her” because “she did the key experimental work.” And her role didn’t end there. Her critique of an early Watson and Crick theory had sent them back to the drawing board, and her notebooks show her working toward the solution until they found it; she had narrowed the structure down to some sort of double helix. But she never employed a key tool – the big 3-D molecular models that Watson and Crick werefiddling with at Cambridge.
It was Watson who fit the final piece into place. He was in the lab, pondering cardboard replicas of the four bases that, we now know, constitute DNA’s alphabet: adenine, thymine, guanine and cytosine, or A, T, G and C. He realized that “an adenine-thymine pair held together by two hydrogen bonds was identical in shape to a guanine-cytosine pair.” These pairs of bases could thus serve as the rungs on the twisting ladder of DNA.
Here – in the “complementarity” between A and T, between C and G – lay the key to replication. In the double helix, a single strand of genetic alphabet – say, CAT–is paired, rung by rung, with its complementary strand, GTA. When the helix unzips, the complementary strand becomes a template; its G, T and A bases naturally attract bases that amount to a carbon copy of the original strand, CAT. A new double helix has been built.
Watson’s famous “Aha!” was but the last in a long chain. It was Crick who had fastened onto a chemist friend’s theoretical hunch of a natural attraction between A and T, C and G. He had then championed the complementarity scenario – sometimes against Watson’s resistance – as a possible explanation of “Chargaff’s rules,” the fact that DNA contains like amounts of adenine and thymine and of guanine and cytosine. But it was Watson who had first learned of these rules.
As Horace Freeland Judson observed in “The Eighth Day of Creation,” this sort of synergy is, above all, what Rosalind Franklin lacked. Working in a largely male field in an age when women weren’t allowed in the faculty coffee room, she had no one to bond with – no supportive critic whose knowledge matched her gaps, whose gaps her knowledge matched.
Writing up their findings for the journal Nature, the famously brash Watson and Crick donned a British reserve. They capped a dry account of DNA’s structure with one of the most famous understatements in the history of science: “It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for thegenetic material.” They faced the question of byline: Watson and Crick, or Crick and Watson? They flipped a coin.
The double helix – both the book and the molecule – did nothing to slow this century’s erosion of innocence. Watson’s account, depicting researchers as competitive and spiteful – as human – helped de-deify scientists and bring cynicism to science writing. And DNA, once unveiled, left little room for the ethereal, vitalistic accounts of life that so manypeople had found comforting. Indeed, Crick, a confirmed agnostic, rather liked deflating vitalism – a mission he pursued with zeal, spearheading decades of work on how exactly DNA builds things before he moved on to do brain research at the Salk Institute for Biological Studies in La Jolla, Calif.
Watson drifted from pure science into administration. As director of the molecular-biology lab at Cold Spring Harbor, N.Y., he turned it into a scientific powerhouse. He also served as head of the Human Genome Project, absorbing some fallout from the high-energy ethical debates whose fuse he and Crick had lighted nearly four decades earlier.
As the practical and philosophical issues opened by the double helix continue to unfold, policy, philosophy and even religion will evolve in response. But one truth seems likely to endure, universal and immutable. It emerges with equal clarity whether you examine the DNA molecule or the way it was revealed. The secret of life is complementarity.