Scientists have taken an historic step forward in unravelling the mysteries of life. Researchers in the UK and the US have mapped all the genes in a small worm called Caenorhabditis elegans. It is the first animal for which this has been done. It has taken 15 years to complete and will have major implications for human health.

Most people will never have heard of the creature which grows to about 1mm in length and lives in soil or among rotting plants, but it has much in common with man.

Around 40% of the worm's genes - which hold all the instructions to build and maintain the creature - are also found in humans.

This means that a study of C. elegans will also reveal much about the biological processes inside humans.

Miniature humans

Dr John Sulston has worked on the project from the beginning

C. elegans may be a much simpler lifeform but it also begins life as a single, fertilised cell and undergoes a series of cell divisions as it grows into an adult animal.

During this process, it also develops complex tissues and organ systems. It even has a nervous system that can detect odour, taste, and respond to temperature and touch.

"In a wonderful way, they are like miniature human beings," says Dr John Sulston, the director of the Sanger Centre at Cambridge where much of the mapping has been done.

"By looking at the genes that are needed to make worm muscles, we can learn quite directly about the genes that make human muscles - because they are the same."

According to a report published in the journal Science, the worm's genetic material is packaged on to six chromosomes - long, tightly coiled strings of the chemical DNA. The genes, which are defined sections of the DNA, number more than 19,000. About 40% of them match those in other organisms - 60% are unknown and will need further explanation.

Huge undertaking

Getting all this information has been a huge undertaking for scientists at the Sanger Centre and at the Washington University School of Medicine, St. Louis, in America. In the early days, it was a very slow process. But the advent of special sequencing machines, which can work around the clock "reading" small sections of DNA, has allowed the genome to be mapped more quickly.

Much of the sequencing is automated

The Internet has also proved to be an invaluable tool, enabling scientists to share data. Much of the worm information was automatically posted on the Net as it came out of the sequencing machines.

These automation techniques will also speed-up the bigger and more important task of mapping the human genome, estimated to contain about 100,000 genes. 2003 is now the target date set for the completion of this project. Again, the Sanger Centre will play a major role providing about a third of the sequence.

Scientific milestone

Completion of the worm genome is being hailed as a major scientific milestone. "Today is a momentous one for British science," said Professor George Radda from the UK's Medical Research Council which funded the work at the Sanger Centre.

The UK Science Minister Lord Sainsbury said: "The completion of this project is a terrific scientific achievement. This research will ultimately contribute towards interpretation of other genomes, including the human, and help to ensure that we revolutionise healthcare."

Robert Waterston, leader of the St Louis group, said: "We have provided biologists with a powerful new tool to experiment with and learn how genomes function. We'll be able to ask and answer questions we could never even think about before."

Although it has taken until now to complete the worm genome, there are more than 200 labs around the world already engaged in C. elegans research.