IT IS HARD TO EXAGGERATE the sheer intellectual excitement of genetics. What has happened is that genetics has become a branch of information technology. The genetic code is truly digital, in exactly the same sense as computer codes. This is not some vague analogy, it is the literal truth. Moreover, unlike computer codes, the genetic code is universal. Modern computers are built around a number of mutually incompatible machine languages, determined by their processor chips. The genetic code, on the other hand, with a few very minor exceptions, is identical in every living creature on this planet, from sulphur bacteria to giant redwood trees, from mushrooms to men. All living creatures, on this planet at least, are the same “make”.
The consequences are amazing. It means that a software subroutine (that’s exactly what a gene is) can be carried over into another species. This is why the famous “antifreeze” gene, originally evolved by Antarctic fish, can save a tomato from frost damage. In the same way, a Nasa programmer who wants a neat square-root routine for his rocket guidance system might import one from a financial spreadsheet. A square root is a square root is a square root. A program to compute it will serve as well in a space rocket as in a financial projection.
What, then, of the widespread gut hostility, amounting to revulsion, against all such “transgenic” imports? This is based on the misconception that it is somehow “unnatural” to splice a fish gene, which was only ever “meant” to work in a fish, into the alien environment of a tomato cell. Surely an antifreeze gene from a fish must come with a fishy “flavour”. Surely some of its fishiness must rub off. Yet nobody thinks that a square-root subroutine carries a “financial flavour” with it when you paste it into a rocket guidance system. The very idea of “flavour” in this sense is not just wrong but profoundly and interestingly wrong. It is a cheerful thought, by the way, that most young people today understand computer software far better than their elders, and they should grasp the point instantly. The present Luddism over genetic engineering may die a natural death as the computer-illiterate generation is superseded.
Is there nothing, then, absolutely nothing, in the misgivings of Prince Charles, Lord Melchett and their friends? I wouldn’t go that far, although they are certainly muddleheaded. The square-root analogy might be unfair in the following respect. What if it isn’t a square root that the rocket guidance program needs, but another function which is not literally identical to the financial equivalent? Suppose it is sufficiently similar that the main routine can indeed be borrowed, but it still needs tweaking in detail. In that case, it is possible that the rocket could misfire if we naively import the subroutine raw. Switching back to biology, although genes really are watertight subroutines of digital software, they are not watertight in their effects on the development of the organism, for here they interact with the environment furnished by other genes. The antifreeze gene might depend, for optimal effect, on an interaction with other genes in the fish. Plonk it down in the foreign genetic climate of a tomato, and it might not work unless properly tweaked (which can be done) to mesh with the existing tomato genes.
What this means is that there is a case to be made on both sides of the argument, and we need to exercise subtle judgment. The genetic engineers are right that we can save time and trouble by climbing on the back of the millions of years of R & D that Darwinian natural selection has put into developing biological antifreeze (or whatever we are seeking). But the doomsayers would also have a point if they softened their stance from emotional gut rejection to a rational plea for rigorous safety testing. No reputable scientist would oppose such a plea. It is rightly routine for all new products, not just genetically engineered ones.
A largely unrecognised danger of the obsessive hysteria surrounding genetically modified foods is crying wolf. I fear that, if the Green movement’s high-amplitude warnings turn out to be empty, people will be dangerously disinclined to listen to other more serious warnings. The evolution of antibiotic resistance among bacteria is a vicious wolf of proven danger. Yet the menacing footfalls of this certain peril are all but drowned out in the caterwauling shrieks over genetically modified foods, whose dangers are speculative at most. To be more precise, genetic modification, like any other kind of modification, is good if you modify in a good direction, bad if you modify in a bad direction. Like domestic breeding, and like natural selection itself, the trick is to introduce the right new DNA software. The realisation that software is all it is, written in exactly the same language as the organism’s “own” DNA, should go a long way towards correcting muddled thinking.
Then again, as we discover more about the genetic code and the way it works, doubters will begin to recognise the potential benefits. Building on the Human Genome Project, the Human Genome Diversity Project focuses on those relatively few nucleotide sites that vary from person to person and from group to group. The implications for medical science are enormous.
Hitherto, almost all medical prescribing has assumed that patients are pretty much the same and every disease has an optimal cure. Doctors of tomorrow will be more like vets in this respect. Doctors have only one species of patient, but in future they will subdivide that species by genotype, as a vet subdivides his patients by species. For the special needs of blood transfusions, doctors already recognize a few genetic typings (OAB, Rh) etc. In the future, every patient’s personal record will include the results of numerous genetic tests: not their entire genome (that will be too expensive for the foreseeable future) but, as the century goes on, an increasing sampling of the variable regions of the genome, and far more than the present blood group typings. The point is that for some diseases there may be as many different optimal treatments as there are different genotypes at a locus — more, even, because genetic loci may interact to affect susceptibility to disease.
Another important use of the genetics of human diversity is forensic. Precisely because DNA is digital, like computer bytes, genetic fingerprinting is potentially many many orders of magnitude more accurate and reliable that any other means of individual identification. Moreover, identity can be established from a tiny trace of blood, sweat or tears (or spit, semen or hairs).
DNA evidence is widely regarded as controversial and it is easy to see why. Human error can obviously vitiate the accuracy of the method. But that is true of all evidence. Courts are already accustomed to taking precautions to avoid the muddling up of specimens, and such precautions now become even more important. DNA fingerprinting can establish, infinitely far beyond all reasonable doubt, whether a smear of blood came from a particular individual. But obviously you must test the right smear.
The idea of a nationwide database, in which all citizens’ DNA fingerprints would be held, is now being discussed. I don’t see this as a sinister, Big Brotherish idea, but many people would want to stop well short of a nationwide database because they have something to hide, not from the law but from each other. A surprisingly large number of people, of all ages, are genetically unrelated to the man they think is their father. To put it mildly, it is not clear that to disillusion them, with conclusive DNA evidence, would increase the sum of human happiness.
If a national DNA database were in place, it might be hard to control unauthorised access to it. If a tabloid newspaper were to discover that the official heir to a dukedom was actually sired by the gamekeeper, the consternation in the College of Heralds might be mildly amusing. But in the population at large it doesn’t take much to imagine the family recriminations and private misery that could flow from freely available information of true paternity. Nevertheless, the existence of a national DNA database wouldn’t alter the situation much. It is already perfectly feasible for a jealous husband, say, to take a saliva or blood sample from one of his supposed children and compare it with his own, to confirm his suspicion that he is not the real father. What the national database could add is a swift computer search to find out who, out of all the males in the entire country, is!
The study of human diversity will bring other radical changes to the way we manage our lives. It is possible that, by the end of the 21st century, doctors will be able accurately to predict the manner and time of death of everybody, from the day they are conceived. At present this can be achieved only for possessors of genes such as Huntington’s Chorea, a horrible disease which waits till early middle age before killing you. For the rest of us, all that is possible is the vague statistical forecast of the life insurance actuary, based on our smoking and drinking habits and a quick listen through a stethoscope. The whole life insurance business depends upon such forecasts being vague and statistical. Those who die old subsidise (the heirs of) those who die young. If the day comes when deterministic forecasting becomes universal, life insurance as we know it will collapse.
That problem is soluble (presumably by universal compulsory life insurance with no individual medical risk assessment). What will be less easy to solve is the angst which will hang over everyone’s psychology. As things are now, we all know we are going to die, but most of us don’t know when, so it doesn’t feel like a death sentence. That may change, and society should be prepared for difficulties as people struggle to adjust their psychologies to it.
Extracted from A Devil’s Chaplain and Other Selected Essays by Richard Dawkins, edited by Latha Menon. Published by Weidenfeld & Nicholson, £16.99. Available through the Times Bookshop at £13.59 plus £1.95 P&P (0870 160 8080)
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