Scientists have launched a major international initiative to systematically uncover the function of each of our genes.

They hope it will provide vital information about how cancer disrupts the normal functioning of our cells – and lead to new drug treatments to stop this happening.

The Human Genome Project has enabled scientists to identify all the genes that make up mankind.

But the next stage is work out what each of these genes do.

This has been made possible by the discovery of a process called RNA interference which is used by the body to switch off individual genes while leaving all others unaffected.