Putting double helix in its place

This year sees the 50th anniversary of the double-helix model of DNA. There is already much celebratory retrospection, combined with some wary commentary on what we might do with our own DNA now that the Human Genome Project has told us (almost) all about it. And the twisted strands of the molecule of the genes are an emblem of a defining moment of 20th-century science, and of a hitherto invisible beauty at the heart of life.

Yet, as often with emblems, it is hard to see clearly. The image of the double helix has become a modern icon, the stuff of a thousand computer animations, web tutorials, and logos - it is the secret of life, the master molecule, the chemical that controls all our destinies. And if the significance of DNA is overblown, so is the impact of its discovery. In 1968 James Watson's artful memoir The Double Helix presented science as a fierce competition in which the smartest team won, but also as an appealing kind of play. Twenty years later, the brilliant BBC film Life Story was kinder to the losers (notably Rosalind Franklin). But the film-makers could not resist Watson's idiosyncratic picture of scientific life in postwar Cambridge, with its odd mix of intensity and indolence, all au pair girls, lunches at the Eagle and afternoon tennis. And both film and book underscored the notion that DNA alone was the key to a new science, molecular biology.

Soraya de Chadarevian's ambitious book does not set aside this myth-making but incorporates it in a richly contextualised account of the emergence of molecular biology. Her study is rooted in Cambridge, the prime location for the elucidation of the double helix, and for much else important to the emerging discipline, and especially in the research unit that began as a minor appendage to the Cavendish Laboratory and eventually grew into the Medical Research Council's Laboratory for Molecular Biology (LMB).

Although, as her subtitle indicates, the book is about the second half of the 20th century, perhaps the key moment in Cambridge was Lawrence Bragg's elevation to the Cavendish chair in physics in 1938. Bragg, along with his father, had pioneered the technique of X-ray crystallography, and he was anxious to support a young Viennese research assistant, Max Perutz, who was one of the few people ready to try applying the technique to structures of the massively complex protein molecules found in living cells. After the war, Perutz was joined by John Kendrew, and Bragg won support from the MRC for a two-man venture rather grandly titled the Unit for the Study of the Molecular Structure of Biological Systems.

At the time, this was part of a wider MRC effort, not in molecular biology, but in biophysics - it was in the physicists' legendary Cavendish Laboratory, after all. De Chadarevian meticulously traces the place of biophysics in the heady postwar expansion of British science, and how the unit gradually attracted other workers marked both by their wartime experiences and by the conviction that physics and chemistry could deliver new approaches to biological problems. This was what made it such a happy location for the DNA duo Francis Crick, then a PhD student, and Watson, a visiting postdoc, in the early 1950s.

But, as she also shows, the triumph of the double helix, far from boosting the unit's fortunes, made few headlines at the time. In fact, it coincided with a crisis for the biological researchers in the Cavendish. When Bragg left Cambridge in 1953, his successor Nevill Mott pointed out that they were not doing any physics, and he wanted their space for people who did.

The budding molecular biologists spent the next five years in a prefabricated hut just outside the Cavendish, the university's best effort to deliver on an undertaking to the MRC to accommodate the unit if the council paid for it.

In time, they moved to new premises, when the LMB proper was built for the expanded MRC Unit, now joined by Fred Sanger's group from biochemistry with their expertise in sequencing proteins and, later, DNA. Now the label molecular biology was firmly attached to the enterprise, and the new laboratory became the renowned home of more Nobel laureates than many whole countries, and the breeding ground for legions of postdocs, who exported its style around the world.

De Chadarevian is especially good on the political negotiation behind all this, but has new facets of the story, too. The importance of an early engagement with computers for the volumes of calculation needed to derive atomic locations in proteins from X-ray reflections, led by Kendrew, merits a whole chapter. We follow the early prominence of molecular biology on TV science programmes, when the protein models finally built by Perutz and Kendrew were vital visual props for new science. There is more on the role of Sydney Brenner, Perutz's eventual successor as head of the LMB, and of Kendrew's involvement in national science policy and in the international promotion of the European Molecular Biology Laboratory established in Heidelberg in the 1970s.

The result is a composite portrait of the ways a new science is shaped by local circumstance. The lengthy span covered by the book means that we hear much less about events after the late 1970s, and the later emergence of a whole "genome campus" around the Wellcome Trust's Sanger Centre. And the intensity of the local focus leaves some issues unresolved. Why did the Brenner-inspired effort to fashion the nematode worm into a tractable model organism for studies of development - and eventually genomics - succeed spectacularly well in Cambridge but stall in Paris, for example?

Overall, though, the book is a worthy complement to the two most important earlier works on this new science, Robert Olby's pioneering The Path to the Double Helix and Horace Judson's romantic but compelling The Eighth Day of Creation . It will have less appeal to the general reader; Judson, especially, is a country mile ahead of de Chadarevian as a writer. But scholars will read all three. And there will be even less excuse to fall into the "Boy's Own" DNA fetishism promoted by Watson's own Double Helix , even if anniversary fever does take hold.

Jon Turney is in the department of science and technology studies, University College London.