Wednesday, November 25, 2020

The Human Side of Science: Watson's The Double Helix

When first published in 1968, James Watson’s The Double Helix received extensive praise and comments. The only contribution that this current essay has to add to the discussion is what a biologist, me, thinks about it 52 years later. It is the autobiographical story of how Watson and his friend Francis Crick discovered the structure of DNA. Before this discovery, it was possible for biologists to think that DNA was not what genes are made of. After the discovery, it became obvious how DNA could contain, and transmit, genetic information. Francis Crick was not exaggerating very far when he said that they had discovered the secret of life.

When it was published, this book was a best-seller. Today, no editor or agent would touch a book for the popular market that contained the word pyrimidine. At the time, Watson was hailed as a hero, and he, along with Francis Crick and others, received the Nobel Prize for this discovery. He was a young American scientist working in England. Today, the general public has largely forgotten Watson, in retirement at age 92, especially after he made comments that were interpreted to mean that some ethnic groups were genetically superior to others. The truth, not surprisingly, is in between these extremes. He deserved his acclaim, although he was and is a flawed hero.

The main cause of his book’s success was that readers in general were surprised that scientists are regular people who have motivations in their day-to-day lives that are like anyone else’s. They get up and go to work, and some days are better than others. Some days are filled with elation, others gloom, most in between. The way scientists evaluate their colleagues is, as for everyone else, based partly on merit and partly on personal likes and dislikes. For example, Watson said that British scientists looked down on him as an uncultured American with unkempt hair.

Watson also felt antagonism toward one of the few women scientists, Rosalind Franklin (“Rosy”), because she seemed to him temperamental. He and other scientists built their schedules around not having to share a cab ride with Rosy, which took some effort since younger scientists at the time earned so little money they could not afford a car or even a single-person cab fare across town. At one point, in Watson’s recounting of events, a fistfight nearly broke out with Rosy. Shocked by Rosy’s untimely death, Watson re-evaluated his view of her, and concluded in the epilogue that Rosy was honest and generous, and before her death all hostility and bickering between them had been forgotten. I wonder if Rosy thought so. Watson was dismissive of women in general; he thought many of them were pretty (especially French exchange students) but, speaking of Crick’s wife Odile, he said that any idea of putting science into Odile’s head went against her convent upbringing. Even today, women scientists encounter a little bit of perhaps subconscious “Don’t bother your pretty head with this stuff” from male colleagues. Watson had a little, maybe more than a little, of this prejudice, which was common at the time the book was written.

The general public thought, and perhaps still thinks, that we scientists advance our understanding of the world in a step by step and entirely logical fashion. This is partly the fault of us scientists: we present “the scientific method” as something that an unemotional computer could do. This myth of science has been recently exploded by two books: my Scientifically Thinking [] and James Zimring’s What Science Is and How It Really Works. But in reality scientists have lurches forward and backward in our understanding, and a seemingly trivial event can open the door to understanding.

Watson struggled mightily to force the data to fit ideas that turned out to be totally wrong. The first was that DNA was a triple helix, not a double helix. The next was that the strands were held together by magnesium ions. It was Rosy who pointed out his error to him: water would just wash away the magnesium. The next was that the bases met in the middle of a double helix, but they were the same bases: A opposite A, T opposite T, etc. He got very enthusiastic about his ideas which quickly crashed. He told his colleagues all about the triple helix, but was quickly proved to be wrong, a very public humiliation; and as for his same-base pairing, he wrote a letter to the most famous chemist in the world, Linus Pauling, twelve hours after thinking of it, and within 24 more hours he knew it was wrong. The idea for complementary base pairing, rather than same-base pairing (the now famous A opposite T and C opposite G), came to him when he was fiddling around with cardboard models of the bases on what had promised to be yet another ordinary day.

Scientists also confront prevailing political prejudices. Today, climate scientists face the unbridled hostility of political conservatives about global warming, and even medical scientists are told to shut up about insisting on Covid masks. Back in the 1950s, the most famous chemist in the world, Linus Pauling, could not get a passport to England because Sen. Joseph McCarthy considered Pauling a communist, because Pauling called for world peace rather than a nuclear arms race.

Science also has its own internal esthetics. Once Watson and Crick figured out the double helix structure with complementary bases in the middle, it not only explained all the known facts (such as Chargaff’s rule and X-ray diffractions) but he felt that “…a structure this pretty just had to exist.” Apparently even Rosy agreed, which, he implied, she seldom did. As shown in this image, Rosy’s careful work with X-ray diffractions was a major step in understanding the structure of DNA.

Most younger people today, even science majors, may never have heard of Watson. They may not know that there was ever a time when the structure of DNA was not known. The Double Helix gives us a glimpse back into a world that was eager to know the secret of life, and into a life that exemplified the episodic nature of science.


  1. The Triple Helix was Linus Pauling's pet theory, not Watson and Crick's