In the wild, C. elegans lives in soil and feeds voraciously on any bacteria or other micro-organisms it can find. It grows from egg to adult in three days (one-third of the time for a fruit fly), except when food is scarce, when it can hang about in a non-breeding larval form for several months. Most adults are hermaphrodites and produce several hundred offspring through self-fertilization. Males arise occasionally, perhaps at a rate of one in a few hundred, and mating provides the possibility for genetic mixing which allows for more rapid evolution. The worm's anatomy is quite simple, but although it lacks many of the physiological features of higher animals, such as a heart, lungs and bones, it can still carry out many basic tasks: moving, feeding, reproducing, sensing its environment and so on. It consists basically of two tubes, one inside the other. The outer tube includes the skin, muscles, excretory systems and most of the nervous system; the inner tube is the gut. It moves by contracting its dorsal and ventral muscles alternately, arching its body into a series of S-shaped curves.

The worm is, moreover, well suited to the kind of investigation Sydney had in mind. It is easy to keep and breed in the laboratory, living happily in petri dishes that have been sown with lawns of Escherichia coli bacteria. You can even keep them in suspended animation in the freezer for years at a time, allowing you to preserve stocks of different strains of the animal. Both larvae and adults are transparent, so that, given a good enough microscope, you can see not only the internal organs of living animals but even individual cells. The adult hermaphrodite usually has exactly 959 cells, not counting the egg and sperm cells. (For comparison, a fruit fly has more cells than this in just one of its eyes, and the human body has 100 trillion.) Its genome is made up of 100 million bases divided into six segments, or chromosomes.

Sydney hoped that he would be able to establish direct links between the worm's genes and its development from egg to adult, following the classic route of geneticists, in use since the first decades of the twentieth century. With a fast-breeding species, such as a worm or a fruit fly, occasional changes arise in the DNA that make the animal look or behave abnormally. These changes are known as mutations, and the altered animals as mutants. Geneticists soon developed a variety of techniques to increase the normal mutation rate. In the 1960s there was no way to analyze the DNA directly, but by cross-breeding mutants and looking at the patterns of inheritance in later generations you could map the relative positions of the mutated genes on the chromosomes. The closer together two mutations lay on a chromosome, the more likely they were to be inherited together. As well as mapping the genes, Sydney hoped, through careful microscopy and biochemistry, to discover exactly what was going wrong in mutant worms at the level of cells.

Assisted by a succession of young researchers, most of them American, Sydney was initially very successful in finding mutants and mapping the affected genes along the chromosomes, confounding those skeptics who had said that the worm was so boring in appearance and behavior that he would never be able to distinguish the mutants from the rest. But the timescale of the whole enterprise turned out to be longer than Sydney anticipated. Genes almost always work in concert, rather than solo-only very rarely is it possible to follow a direct line through from one gene to one function. Even so, the whole thing took off in a larger way than Sydney could have predicted because his intuition led him to an animal with tremendous potential for research.

As was typical of Sydney's style-indeed, the style of the LMB as a whole-on my arrival I was given about a meter of space at the bench in a crowded lab and more or less left to get on with it. Sydney and Francis believed that keeping the lab tightly packed encouraged people to interact, and that `desks encouraged time-wasting activities.' I found myself among a group of young researchers, astonished that we were being paid to do what we wanted to do anyway, and knowing that we had no-one to blame but ourselves if we did not succeed. I compared notes with another new arrival, amazed like myself by the pride, to the point of arrogance, that we found at the lab. `Who do these people think they are?', I remember him saying. But gradually we realized that they had a right to be proud, and as time went on we acquired some of that pride ourselves, though personally I was convinced that I could never do well enough to live up to the past glories of the LMB.

The laboratory was then and still is one of the world's top centers for research into the molecular basis of life. This was the place, more than any other, where the field of molecular biology had been invented. Its unique ethos undoubtedly played a role in shaping my development as a scientist. It grew out of a fortunate combination of circumstances in the years after the Second World War. Many academic scientists had engaged in war-related research, and the results were spectacular: radar, high-speed computing, antibiotics, and nuclear technology all had their origins in wartime research. It dawned on the government of the day that investment in science could have a long-term payoff. Up to the end of the 1930s there was little opportunity to do research in Britain if you didn't have a university teaching appointment or a private income. But ten years later it suddenly became easier to get grants, generous ones, from government-funded bodies such as the Medical Research Council (MRC) or the Department for Scientific and Industrial Research. This sudden largesse coincided with one of the most exciting periods in the history of biology, as more and more people began to apply the methods of physics and chemistry to biological problems.

Lawrence Bragg was a physicist who headed the Cavendish Laboratory, the physics department of Cambridge University. As a young man, Bragg had pioneered the technique of X-ray crystallography that made it possible to study the three-dimensional arrangement of atoms in molecules, including biological molecules. Among his staff was a meticulous, quietly spoken Viennese émigré chemist called Max Perutz. Perutz, together with a young colleague, John Kendrew, also a chemist, was trying to decipher the structure of the blood protein hemoglobin. X-ray crystallography worked well for small molecules, but proteins contained thousands of atoms and progress was slow. Bragg, an extremely influential figure in British science, was an enthusiastic supporter of Perutz's work. In May 1947 he wrote to the Secretary of the MRC asking for the funds to establish Perutz's group `on a more permanent basis.' Within months the MRC agreed to support a Unit for Research on the Molecular Structure of Biological Systems, with Perutz at its head.