In sheer hype, the Human Genome Project comes a close second to the millennium. Last month, our millenarian concerns and celebrations overshadowed the news that the scientists working on the project had completed the sequence of a human chromosome. The chromosome in question is number 22, one of the 23 basic bundles of DNA in which our genes are grouped. The achievement is considered as one of the most important in the history of science, at least as important as Mendel's discovery of the gene in 1866.
Scientists like to portray the human genome as a "Book of Life". The complete sequencing of chromosome 22 means that we have completed the first chapter. The finished book, the hype goes, will transform life as we know it. According to a recent article in Nature magazine, it will change "the way we see ourselves as profoundly as did the momentous books of the first two millennia - the great books of religion and the Origin of Species" and will banish disease, illness and human disorders for ever.
There are about 27 human disorders associated with changes to genes on chromosome 22. Knowing all the genes in this chromosome enables us to identify genes that cause these disorders. So, scientists tell us, we are well on our way to finding cures for leukaemia and other forms of cancers, schizophrenia and disorders of foetal development and the nervous system. Within the next decade, when all the human genes are identified, we will have personalised medicine. Doctors will be able to look at a person's DNA, predict his or her chances of getting diabetes, asthma, heart disease, mental illness or some form of cancer, and prescribe medicine best suited to the person's genetic make-up. Within 30 years, we will be able to walk into a chemist and get a genetic blueprint of ourselves. Within 50 years, we will all be genetically modified into perfect health and expect to live a good hundred years.
Genetic therapy may well usher in real benefits for humanity, but is all this hype necessary? Is it necessary for genetic technology to be presented as a panacea for everything from abolishing world hunger to preventing all diseases including housemaid's knee, to providing designer babies for those who can pay? The simple answer is, yes. The Human Genome Project is a publicly funded project. To ensure that money supply remains open, it has to be sold to the public, as well as to governments, as the elixir for the millennium.
Yet, ironically, these lofty promises could lead to public disillusion not just with the Human Genome Project but with genetic technology in general - particularly if the public discovers that scientists are being a bit economical with the truth.
For example, the "complete DNA sequence of human chromosome 22" is not all that complete. Chromosome 22 has a catch: the published sequence has 11 un-sequenced gaps. Although this accounts for only about three per cent of the sequence, the missing bits are important to the overall puzzle. Normally the DNA is sequenced by isolating small bits of chromosomes inside bacterial clones that multiply to produce DNA segments that can be made into sequences. But some sequences do not have a clone - hence the gaps. Furthermore, many pieces of DNA behave weirdly when scientists try to work with them. Scientists have no way of telling whether these exceptional bits of the DNA are the least, or the most, important of the lot.
There is a big difference between knowing the sequence of a chromosome and coming up with a cure for a human disorder. This was illustrated by the tragic death of an otherwise fit 18-year-old man with an inherited enzyme deficiency following treatment at the University of Pennsylvania's Institute for Human Gene Therapy. He died four days after doctors injected massive doses of a genetically altered virus into his liver; he was the first patient to die because of gene therapy itself.
The case highlights the simplistic foundations of the shotgun technology of applied genetics. It is as if scientists had discovered the beads on the DNA string, labelled "toe", "frost resistance", "musicality" and so on, in a neat sequence. It seems so easy to "insert the gene" for one desired property into the DNA of another, with some sort of microscopic tweezer. But it is only when something goes wrong that scientists have learnt that it is more complicated.
This does not condemn gene therapy. We had many such setbacks during the early years of heart surgery. It is possible that, after further trials, gene therapy could become as routine as heart transplants. But hype plus failure is a formula for public suspicion.
It also leads to self-delusion among scientists. This happened in the early days of nuclear power. This was once sold as the source of energy so cheap and plentiful that electricity meters would not be necessary. It was going to transform the benighted Third World into a world of light and abundance.
Then the Three Mile Island near-meltdown brought many nuclear physicists back to Earth with a bump. A cartoon in an American newspaper summed it up. It showed a group of startled executives gazing at a screen on which was projected a large diagram of the atom, its electrons whizzing in their orbits around the central nucleus. But the nucleus was actually a button nose; and a pair of large semicircular ears were appended near the top. No caption was necessary. For America, it signified that the "peaceful atom" and its promise of cheap energy had turned out to have the same sophistication and quality as a 99-cent Mickey Mouse wristwatch.
Genetics is in danger of following suit. Scientists need to control their tendencies to tell the public, their employers and themselves that they are about to solve all the problems of humanity. Gene technology does not need to be oversold. Rather, we need to discuss openly and truthfully its benefits and hazards. Otherwise, at best, it may turn out to be as much of a non-event as the millennium - and its bug. At worst, it may turn out to be the hubris of scientific endeavour that finally yields its nemesis.
