[
Nature,
1992]
Induction is the process in development in which the fate of one cell mass is determined by another. A simple example occurs during vulval development in the nematode Caenorhabditis elegans: a gonadal cell called the anchor cell induces three neighbouring cells to embark on a programme of cell division and morphogenesis, which culminates, in a few hours, in the formation of a vulva. On page 470 of this issue, Hill and Sternberg report strong evidence that they have identified the anchor-cell signalling molecule, which they find is a member of the EGF (epidermal growth factor) group of growth factors.