A fertilised human egg contains a set of instructions which will enable it to give rise to a human being who looks very much like all other human beings. But how is this actually accomplished? How do the cells of a developing embryo move around. become different, give rise to forms like the hand and the brain?
Professor Lewis Wolpert of the Middlesex Hospital Medical School has made a major contribution to the understanding of these problems, and In conversation with John Mnddox he discusses what is now known about the way cells.in an embryo behave.
Producer ALISON RICHARDS
