Once upon a time John Sulston was talking to two teenage girls on a train. He was a bearded hippie type, but friendly and serious: a safe man to talk to. Still, when he told them about his work, they giggled ferociously, because he explained that he had spent ten years or so dissecting in intimate detail tiny, transparent, hermaphrodite nematode worms. He wasn't offended by their laughter. He had often argued with his friends that it was absurd for scientists to be paid more than dustmen, not because dustmen were more useful, but because scientists had so much more fun.
At a press conference about fifteen years later, the same man, trimmed all round to look respectable, but still serious and friendly enough to be a really effective revolutionary, sat alongside Tony Blair to hear the prime minister describe his work as 'a revolution in medical science whose impact can far surpass the discovery of antibiotics' and 'the first great technological triumph of the twenty-first century'.
This was modest compared to the estimate of Sulston's immediate boss, Mike Dexter, who reckoned that 'This is the outstanding achievement not only of our lifetime but in terms of human history . . . this code is the essence of mankind.'
Blair and Mike Dexter were hyping the human genome project, not the worm on which Sulston had spent most of his life working. But the worm's genome had been sequenced first; in 1998, it became the first multi-cellular organism to have all its dna listed and read. Sulston, his friend Bob Horvitz and his former boss Sydney Brenner, who invented and drove the worm project, shared the Nobel prize for physiology and medicine in 2002 for their worm work, not for the human genome. The human genome project grew directly from the work that had been done on worms. It would have been done eventually without the worm; but it would have been done much more slowly, perhaps less thoroughly; and certainly less publicly, and so far less usefully. Very probably, without Sulston the genome sequence would have been locked up and almost completely useless in the vaults of some American biotech company.
So you can't understand the story of the human genome without looking at the story of the worm. Neither can you really understand the culture and the attitudes among scientists that made the human genome project look worthwhile without looking at the cultures that shaped them; and the worm formed an important part of that. Its history spans almost the whole of molecular biology, which has gone in fifty years from being a field without textbooks, or even a name, to the gigantic multi-billion-dollar industries of today.
Anyone listening to the hype about the human genome could be pardoned for wondering, Where is the benefit? For all the thousands of millions of pounds spent on the enterprise, not a single cure for a single disease has been found directly from the sequence. Even the language of news reports has changed so that they now talk about 'a gene that contributes to' some condition, rather than 'the gene for'. The stock price of Celera, the company that produced a private version of the human genome sequence, fell from $240 to $10 in less than three years; and we are told that the effort (and money) needed to decode the genome will be dwarfed by the effort and money needed to examine the proteins that the genome specifies. Only when they are all understood will all the promised benefits to humanity appear.
The worm story helps to understand why this has happened. No one stood to make a fortune from the study of nematode worms. No one cared or cares for the soul of a nematode (though there is a rumour that the cell containing it was found and discarded by researchers in 1978). Their motives for reading the worm's genome were purely scientific. Only by understanding why and how it was done to the worm can one hope to understand the real reasons for sequencing the human genome, and the real benefits that might accrue from it.
But the importance of the worm goes deeper. This tiny scrap of brainless voracity is far more complicated than it seems. Learning about it has told us a great deal about the fundamental mechanisms of our own bodies. Anything alive can reproduce and eat, and the overwhelming majority of living things on this earth are bacteria. But the life that we notice - which means anything large enough to see - can do more than reproduce and eat or even move. It can grow. When its cells divide, they don't split off into new organisms, but stay linked with the old ones, to make complex, cooperating wholes.
This is so complex and so difficult that most of the genes of any multi-cellular creature are occupied with it: that's why we share about 50 per cent of our genes with a banana.
A banana and a human being - or a worm - are very different. But they are all recognisable, coherent, organised wholes, and this similarity turns out to be almost the most important thing about us. It is certainly the foundation on which all the subsequent differences are built.
The worm, Caenorhabditis elegans, is about as simple as an animal can be. It has only 959 cells that are not eggs or sperm, and all these are known, and all grow in the same way. They are identical from worm to worm. In many ways, the worm is nature's test tube: a transparent organism which might have been created to do experiments in, not least because it has no brain and can't be imagined suffering. But none of this explains why one should want to do all these experiments, and why people so burned to understand.
It is here that the worm shows us most about our own species. Modern science has taught us an enormous amount about the world around us, and extraordinarily little about the worlds within us. There is certainly no scientific explanation for scientific passion, but the history of the worm is full of the devouring lust for knowledge. The people who did it were not really interested in money, or fame outside a limited circle. They were not saints. They were ambitious and competitive, and life was hard for those who failed. But their ambition and competitiveness and their sometimes jealous love were all directed at altruistic ends. They wanted to understand the world. They wanted measurable, solid truths about it. Their Nobel prize was recognition, not the reward they had worked for.
This kind of passion looks extraordinary because it is both ruthless and unselfish. We think that if a businessman works twelve- or eighteen-hour days, neglecting his family, and careless of the world's opinion, this makes sense because he will be rich at the end. But the worm scientists worked like that with no expectation of becoming rich.
Indeed, very few of them did so, and some of the most important ones, among them John Sulston, deliberately turned their backs on great wealth in order to be able to share their discoveries with the world. I don't think that studying our dna will tell us nearly as much about what it means to be human as understanding that kind of passion would.
This purity and focus of vision runs right through the story of the worm, despite the increasing elaboration and expense of the science involved. In some ways, the tiny worm stretches across the whole history of molecular biology, from the original experiments on the smallest possible living things, to the final ambition to have sequenced the dna of everything on the planet - because only then can we properly understand it. There may be a huge change in outward circumstances between the original experiments, conducted in scrounged lab space all round Cambridge, and the global reach of the business now, conducted in hi-tech purpose-built campuses all round the world. But there is a single common thread of a focused ambition running through, and a determination to understand how it is that certain chemicals assemble themselves into stable patterns, and how these patterns combine in the exquisitely complicated and patterned chemical dance of life.
It is an extraordinary story, and all the more extraordinary because all this passion was driven and directed by one man's vision.