Oxford 'gene-hunters' played a major part in unravelling the genetic code for human beings, writes Amanda Castleman

Scientists may soon be able to read us like a book, after cracking the code of human life. This discovery - compared to the invention of the wheel or landing on the moon - could lead to breakthroughs in disease treatment and prevention.

Human DNA is composed of three billion chemical "letters", deciphered by American and British scientists, including hundreds based in Oxford. Many small 'maps' of chromosomes were assembled, like a patchwork quilt, to produce the genome - a blueprint of a human. "Our scientists have been involved at various stages, making maps of chromosomes and cloning large fragments. Oxford has made many contributions," explains Professor Tony Monaco, director of the Wellcome Trust Centre for Human Genetics, based in Headington.

The centre houses about 300 scientists currently involved in the project, but at least ten other Oxford labs have been involved over the last decade.

"We are gene hunters," he says, "We look for faulty genes that give rise to common diseases, such as asthma, adult diabetes, psychiatric disorders, tuberculosis and malaria.

"These diseases have a genetic cause, but it's not as simple as one gene, one problem. Many genes contribute to the disease and we're trying to tease it apart."

The human genome is far from finished, however. The project has mapped 97 per cent of our DNA and sequenced 85 per cent. This rough draft will be polished over the next two to three years. Even then, each person is unique. We share 99.8 per cent of our DNA, but the remaining three million letters mark the difference between, say, Camilla and Gazza.

Then the information - enough to fill 601,500 telephone directories - must be analysed, understood and applied. Companies such as Oxford Biomedica will play a part: already it has developed an efficient way of delivering genes to the brain, using a virus found in horses.

Gene therapy reprogrammes faulty cells, while the virus spreads the cure quickly. Such techniques may someday cure Parkinsons and Alzheimers, heart disease and diabetes.

"It is now conceivable that our children and our children's children will know the term cancer only as a constellation of stars," pointed out President Clinton, as he and Tony Blair announced the breakthrough. The data could allow scientists to banish inherited disorders, screen people for vulnerability to diseases, tailor treatments to an individual's genetic make-up and create thousands of new drugs.

The goal, Professor Monaco stressed, is not "patenting people", but better treatments and prevention. Knowing what triggers disease - and who is most vulnerable - can help decrease risks.

"By the time you get a disease, you are so far along. You could have prevented so much anguish. We're not talking about immortality here. We'll still have to live with disease." Any celebrate the code's potential, such as Richard Dawkins, Professor of Public Understanding of Science at Oxford. "Along with Bach's music, Shakespeare's sonnets and the Apollo space programme, the Human Genome Project is one of those achievements that makes me proud to be human," he says.

Yet others fear the knowledge could lead us horribly astray. Even Tony Blair admitted that science's speed is "deeply unsettling", while concerns about "tailor- made" babies, genetic discrimination and "playing God" abound.

The British government has set up the Human Genome Commission to regulate how the information - posted free on the Internet - is used.

Professor Monaco remains optimistic, however. "In the next step, we'll discover what the genes do, how they interact and turn on and off, which are involved in babies' development and which maintain adults. Now we know all the players.

"Decoding the human genome is a landmark. Progress should go much quicker now," he said. "The next stage of the biological revolution should really accelerate. Oxford scientists will benefit from this discovery more than most."