Frederick Sanger, pioneer of the gene research that will transform medicine, is afraid it will be exploited.

Anjana Ahuja reports

The double Nobel laureate who began the

book of life

There are no plaques or certificates on the walls, no citations on the mantelpiece and no medals lying around. Nothing in this simply furnished house in a quiet Cambridgeshire village would lead you to guess that it belongs to Dr Frederick Sanger, one of only four people to have won two Nobel prizes.

The 81-year-old biochemist sees nothing odd about keeping his prizes, both for chemistry, in the attic. "You get a nice gold medal, which is in the bank," he smiles. "And you get a certificate, which is in the loft. I could put it on the wall, I suppose. I was lucky and happy to get it, but I'm more proud of the research I did. There are some people, you know, who are in science just to get prizes. But that's not what motivates me."

It is this kind of modesty that has kept Sanger, a thin, serious man, from becoming a household name. For it is his work on which the most ambitious science project ever undertaken - the Human Genome Project - is predicated. Sanger's second Nobel prize in 1980 was awarded to him and three colleagues at Cambridge University for discovering a way of sequencing genes. Genes are long chains of DNA molecules; the chains have four types of chemical links, and the order of these links determines what the genes do. Gene sequencing simply means spelling out the order, or sequence, of the links.

Sanger, who won his first Nobel in his own right in 1958 for figuring out the structure of insulin, devised an ingenious method of working out this chemical grammar. The first step was to start manufacturing a replica of the gene under study. The next step was to add a killer chemical that would terminate the replication once it hit a particular link. The scientists repeated the replication, each time adding a different killer chemical and so stopping the replication at a different set of links. By this painstaking method, Sanger and his colleagues were able to map the sequence of links of simple structures such as proteins and viruses.

This was not the usual stuff of Nobel prizes - esoteric research that could be understood only by the scientific elite, and destined for dusty library shelves. The Cambridge research was a potential portal to one of the ultimate goals of science - to write the manual of life by spelling out the chemical composition of every gene in the human body. That almost whimsical aim is close to fruition. Within the next two years the entire human genome will have been sequenced, revealing the order in which the billions of chemical building blocks in the human body are assembled.

Sanger is amazed at the pace of progress: "When I started on proteins, I hadn't thought about anything like that. I used to dream about being able to sequence a protein. What they do now is nothing like I used to do. I was messing about with chemicals and test tubes, and nowadays it's sitting in front of your PC."

While most scientists view the Human Genome Project primarily as a wonderful scientific achievement that will benefit all humanity, Sanger is worried about those who want to make money from it. Top of his list of concerns is Craig Venter, an American biologist who was working on the Human Genome Project until 1998 but then broke away to start a rival project. Venter aims to produce a rough working draft of the genome this summer - beating the publicly funded effort and, more importantly, patenting key findings. This week his company announced it had mapped 90 per cent of the genome.

With much of medicine likely to depend on this research - and with Venter's corporate backers charging a licensing fee every time anybody wanted to use it - the potential   for profit is enormous.

"It doesn't sound very good," Sanger sighs. "I don't know him (Venter) at all really but I think he has the idea that he's going to patent it and sell it off. I think that's bad. I don't think you should patent something that is such an important part of the human body.

"But I can see why people want to do it. Craig wants to be another Bill Gates. People want to make a quick buck. It's not very healthy and the patent laws ought to be looked at." Sanger regrets the research turning into a race for fear the science might be compromised: "I think it's worthwhile doing properly because I don't think we'll do it again. It's got to be got right."

Being intimately acquainted with our genetic make-up will have some extraordinary implications for human beings. We will have the power to know our genetic destinies - to learn whether we are likely to develop diabetes, cancer or heart disease, and to take tailor-made drugs to prevent them. We may choose to select traits in our children.

To some, this amounts to indefensible tampering with nature. Sanger, whose parents both died of cancer, does not subscribe to this. Even as an undergraduate, his aim, he says, was to further medicine and eradicate disease. Helpfully, he does not believe in divine destiny: "I don't think it is playing God. It's a more detailed view of how a human being works. I can't see that knowing the truth can be harmful. I'm not very good at philosophical questions - it's for society to decide what to do with this genetic information.

"My father was a committed Quaker and I was brought up as a Quaker, and for them truth is very important. I drifted away from those beliefs - one is obviously looking for truth but one needs some evidence for it. Even if I wanted to believe in God I would find it very difficult. I would need to see proof."

One would think that a Nobel scientist would have been born to live in a laboratory, but Sanger was happy to retire at 65 and devote himself to his garden. The son of a country GP, he still thinks he owed his 1936 undergraduate call-up to Cambridge to his father's wealth rather than talent, and maintains his career was built on hard work, ambition and persistence rather than genius.

The rewards have been great, including the money that accompanies the Nobel prizes. On the first occasion he was awarded £13,000, and, being the sole winner, he had it all to himself. He used it to take his wife Joan and three children on holidays abroad, and to educate his two sons and daughter. The second time he won a quarter-share of the booty which, two decades after the first windfall, did not really amount to very much.

The Wellcome Trust has honoured him by naming a centre after him. The Sanger Centre in Cambridge is the British home of the international Human Genome Project (the National Institutes of Health near Washington is the other main partner). Sanger pops in there now and again to chat to friends, and appeared at the press conference in December to announce that the sequencing of an entire chromosome had been completed.

But that is where he draws the line. There are no flashy symbols of success - no luxury cars, expensive furniture or landscaped gardens. Sanger, a socialist and conscientious objector, even turned down a knighthood. He didn't care to be called Sir: "A knighthood makes you different, doesn't it, and I don't want to be different. But I did accept an Order of Merit, which is higher, so I suppose there's a bit of snobbery there."