Time will tell

DNA is used as a symbol of hopes and fears in the genetic revolution.

A human figure, naked and male (as far as we can tell in the absence of genitals), turns his face and the palms of his hands to the heavens, like one of the ascending elect in Michelangelo's painting Last Judgement. Standing atop the kind of classical column reserved for military heroes, he adopts a space-filling pose reminiscent of Leonardo da Vinci's famous man tracing the figures of a square and circle with outstretched limbs. He is fringed by a halo of light that obeys none of the laws of terrestrial optics.

This was the image that appeared on the cover of Time magazine on 17 January 1994. It now features in the exhibition “Representations of the Double Helix”, curated by Soraya de Chadarevian and Harmke Kamminga at the Whipple Museum of the History of Science in Cambridge, UK. The cover draws attention to an article inside on “The Genetic Revolution” by Philip Elmer-Dewitt, subtitled “New technology enables us to improve on nature. How far should we go?” Francis Collins of the US National Institutes of Health (now director of the National Human Genome Research Institute) was cited as comparing the challenge with splitting the atom or going to the Moon.

The centrality of DNA to the genetic quest is signalled by its spiralling presence in the figure's thorax and abdomen, reminiscent of a giant structural spine. It is assumed to be an instantly identifiable icon for Time's international readership, recognized even when, as here, the helices twist in the wrong direction. It would be interesting to take a census of how often this reversal has occurred in the 50-year iconography of the great molecule.

We read on the cover that “New breakthroughs can cure diseases and save lives” — a promise that has been more hyped than realized — but the positive connotations are anxiously tempered by the question “how much should nature be engineered?” The eerie, night-time atmosphere of the cover evokes a science-fiction realm in which excitement and fear are mingled, Frankenstein-like.

Such is the fame of DNA that it has featured on at least three other Time covers over a 32-year span: 19 March 1971, 13 September 1999 and 17 February 2003 (in the US edition, but 3 March 2003 in Europe). The most recent of these shows a modern Adam and Eve standing wreathed in golden helices that branch aloft into a fruiting tree of life (or of sinful knowledge?). The lead article on this occasion, written by Nancy Gibbs, deals with “The Secret of Life”, and aims to show how “Cracking the DNA code has changed how we live, heal, eat and imagine the future”.

We take the familiarity of DNA so much for granted that it is difficult to see its high profile as exceptional. How many abbreviated chemical names mean anything in the broader public domain? H2O and O2 are familiar enough, and CO2 has gained prominence in relation to global warming. All three have oxygen in common, which seemed to hold the promise of the secret of life in the late eighteenth and early nineteenth centuries. Like AIDS, HIV and, perhaps, BSE, its acronymic identity has achieved independence from any widespread awareness of its full name or chemistry.

The triumphant story of DNA is marked by signposts that become selectively significant when we retrospectively know where history was taking us. As Robert Olby showed in his recent article in Nature (421, 402–405; 2003), the great majority of papers on DNA up to 1960 made no mention of James Watson and Francis Crick's structure (Nature 171, 737–738; 1953) — it remained something of a 'sleeper'. The laconic visual and verbal presentation of their paper, which was a factor in its slow rise to fame, seems astonishing in retrospect, but we would do well to remember Watson and Crick's acknowledgement that “The previously published X-ray data ... are insufficient for a rigorous test of our structure. So far as well can tell, it is roughly compatible with the experimental data, but it must be regarded as unproved until it has been checked against more exact results.”