DNA is not just "the very foundation of life"; it is also, it seems, the very height of fashion. In using DNA to launch their latest model in the UK, BMW were merely following in the footsteps of another European car manufacturer. For Renault had already appropriated the DNA fingerprint image (along with Professor Steve Jones of University College London) for use in their own TV commercials earlier in the year. In both cases, the car companies used evolution and genetics to convey the notion of progressive improvement through a series of generations.
But, more than this, they used DNA because of its "powerful imagery", as BMW put it in its accompanying literature. Today, this imagery is to be found not only in TV advertisements, but also in company logos and cartoon strips, on billboards, and in perfumes and "alco-pop" drinks. In Britain, a prominent publisher recently advertised its popular science list under the slogan, "Sex, drugs and DNA". Whether this is taken as a spin on sex, lies and videotape, or "sex'n'drugs'n'rock'n'roll", the point remains the same: DNA is glamorous; DNA sells.
In one sense, this is hardly surprising. The spectacular success of molecular genetics in the second half of our century has served to project DNA into the public consciousness in a uniquely powerful way. It may seem hard to believe now, but after Crick and Watson announced their Double Helix in 1953, it took several years before the BBC saw fit to give it any significant radio or TV coverage at all. What seems obvious now - a recent poll in this newspaper showed a clear consensus that Crick and Watson's was the single most important scientific discovery of the 20th century - was not so obvious then. In the Sixties, the Double Helix steadily gained wider currency as a rather beautiful theory of inheritance; but it wasn't until the Seventies that it became clear to most people that this theory could in fact be put to practical use by direct manipulation of DNA itself.
More than anything else, it has been the resulting cascade of new gene technologies that has made DNA so famous. The role of DNA fingerprinting evidence in the OJ Simpson trial probably did more to project DNA into public consciousness than all the popularising efforts of scientists and science journalists put together. Over the period from 1988 to 1996, the British public's factual knowledge about most scientific subjects increased only slightly; but during the same period, the number of people who knew that DNA is the material basis of biological inheritance roughly doubled, from 43 per cent to 81 per cent.
Of course, not everything connected with DNA has been universally welcomed. At the same time that many forensic and medical uses of gene technology have been widely hailed, some agricultural uses of gene technology - for example, in the development of genetically modified (GM) foods - have come under a cloud of suspicion. According to the Prince of Wales, for example: "Mixing genetic material from species that cannot breed naturally, takes us into areas that should be left to God. We should not be meddling with the building blocks of life in this way." (The Prince of Wales's online forum on GM food is at http://www.princeofwales.gov.uk)
This is the view also taken by the food retailer Iceland, which has begun to advertise its products on the basis of the fact that they do not contain any GM ingredients.
Thus, we have a curious situation in which some companies are promoting their products by association with gene technology, while others are doing so by freeing their products from that very same association. In Advertising Land, it seems that it's OK for cars to "evolve"; but it's not OK for plants to be "engineered", even if - according to a report published earlier this week on the regulation of genetic modification in agriculture by the House of Lords Select Committee on the European Communities - such engineering could offer "great potential benefits to agriculture, industry, consumers and even to the environment".
As Monsanto has discovered, opposition to GM foods is greater in Europe than it is in North America. As part of an international research programme designed to map changing attitudes to gene technology in Europe, my colleague George Gaskell, at the London School of Economics, has found that significantly more Europeans than Americans possess what he calls "menacing images" of GM foods. Asked a series of identical questions, 30 per cent of Europeans, but only 7 per cent of Americans, agreed that, "ordinary tomatoes do not contain genes while genetically modified tomatoes do". Similarly, 24 per cent of Europeans, but only 8 per cent of Americans, agreed that "by eating a genetically modified fruit, a person's genes could also become modified".
In other words, it seems that quite a lot of Europeans are inclined to believe two rather scary things: first, that it's only genetically modified foods that contain genes; and second, that by eating such foods a person's own genes could somehow be affected or even infected. Small wonder, you may think, that GM foods have become so controversial in Europe. If the American sociologist Dorothy Nelkin is right in thinking that what she calls "The DNA Mystique" has projected the gene as a cultural icon, then it seems that this icon is powerful enough to evoke anxiety as well as admiration.
Anxiety about DNA is also apparent in the area of medical science. The Human Genome Project is making rapid progress with mapping and sequencing our entire genetic make-up. In just a few years, we shall know the position and the precise structure of every single gene we possess. Of course, we shan't know what all of these genes do. But, even now, there is a long and growing list of genes associated with medically significant characteristics.
In one sense, the simplest of these to deal with are the single genes (such as those for Friedrich's ataxia and cystic fibrosis) that cause serious genetic disease. Once these genes can be easily identified, it is possible to offer genetic counselling to couples who may be at risk of having an affected child. But how shall we deal with genes that merely increase the probability of disease, or genes that are linked with much less serious complaints?
A recent brochure from the pharmaceutical company SmithKline Beecham reviews current research on "a new gene that might affect appetite", as well as work on the genetic basis of heart disease, diabetes, hypertension, Alzheimer's disease, depression and schizophrenia. If you are inclined to doubt that some or all of these diseases are less serious than, say, cystic fibrosis, then simply change the examples to suit your preferences. For the fact is that virtually every significant physical or mental characteristic we possess is going to turn out to be influenced by one or more genes within the human genome.
The vertiginous prospect of knowing - and being able to influence - the genetic roots of the human condition is, rightly, the cause of a great deal of concern. In Britain today, there is a plethora of government advisory committees dealing with different aspects of human molecular genetics. There are committees on genetic modification, on scientific advances in genetics, on genetic testing, on gene therapy, and on "xenotransplantation" (the creation of transgenic animals whose organs may be suitable for transplant into humans); and another committee on genetics and insurance is currently being planned. All of these are in addition to an overarching Human Genetics Advisory Commission and a statutory Human Fertilisation and Embryology Authority.
Another, equally complicated, set of committees looks after the uses of gene technology in agriculture and food production. Not surprisingly, perhaps, the Government is currently reviewing this baroque committee structure involved in regulating the way we exploit our knowledge of DNA, with a view to simplifying it and making it more open and more accessible to the public.
This is obviously important, but I don't think it's the only challenge ahead. As we continue to learn more about the genetics of the human condition, we are continually tempted to credit DNA with almost supernatural powers; to see it almost as a modern, secular substitute for the old, mythological life force. The very success of the molecular geneticists in identifying genes associated with so many different physical and mental characteristics has recently encouraged a great deal of speculation about the existence of "genes for" all sorts of nebulous traits - from mental ability and sexual orientation, to parenting styles and criminality. We await only a full-blown genetic theory of voting behaviour in general elections before handing over the entire domain of the social sciences and humanities to the safe care of biologists.
This is obviously rubbish. We might be tempted to indulge it as mildly amusing rubbish, were it not for the fact (much bemoaned by more thoughtful biologists) that the long-standing myth of the unalterability of genetic traits shows no sign of being displaced in popular culture by a more scientifically realistic idea of the role of genetics in human affairs. With DNA riding high as a cultural icon, it is continually tempting for headline-writers and pundits to lapse into a crude form of genetic determinism in which anatomy (this time in the form of the Double Helix) is destiny.
This is where headlines in the tabloids about "gay genes" ultimately come from; and it's also where a spate of ghastly, fatalistic "don't- help-yourself" books have recently come from in the United States. In a rather different sense, even our own Brian Appleyard trips up over this issue in his recent book, Brave New Worlds (HarperCollins). In typically intemperate style, Appleyard argues that once we accept a genetic approach to the human condition, we must end by conceding to the gene our human dignity and freedom.
If this were true, then modern genetics would indeed be a threat to traditional humanistic (and, indeed, all religious and spiritual) values. In fact, it simply isn't so. Of course, we are made of DNA; but we are also made of sinew and muscle; and besides all that, we're the stuff of dreams. All of these statements are true in their way, but none of them is true as a complete and adequate account of what we are.
When it comes to understanding the evolution of the human race, DNA has special status; for it is through the selection of changes in DNA that human beings evolved. But when it comes to understanding who we are as individual, conscious, free beings, DNA has no special status whatever. It is simply one of the physical ingredients in the mix that went into our development. Knowing more about this ingredient cannot change what we already know about ourselves - that we are feeling, thinking, hopeful creatures; weak and imperfect, to be sure, and much inclined to doubt and indecision, but nonetheless perfectly capable of surprising ourselves and those around us by occasionally choosing to do the right thing.
In all of our current efforts to deal with the implications of what we can do with DNA, we need to make sure that we keep this extraordinary molecule in proper perspective. We can alleviate our condition in this world to a very considerable extent by the wise application of our genetic understanding; but if we are too uncritical in our zeal for DNA as a cultural icon, then we may be tempted to forget what we know about ourselves, and accept instead a crude caricature drawn more from the images created by smart advertising executives than from either science or sober reflection. This would be too high a price to pay for the genetic revolution. Fortunately for us, there is no need whatsoever to pay it.
The author is director of science communication at the Science Museum, and professor of public understanding of science at Imperial College, London