[
Science,
1996]
The one-cell animal embryo, or zygote, faces a daunting engineering task: implementing the architectural plans inscribed in its DNS for building a complex, multicelled body. So, like any sensible construction supervisor, the zygote swiftly divides the project into manageable chunks, assigning some of its progeny to build only gut, for example, and other to make only muscle or skin. Just how each early embryonic cell gets its orders is understood only for the fruit fly Drosophila melanogaster-an achievement that helped win 1995's Nobel Prize in medicine for three developmental biologists. Now, however, the communication lines governing embryonic development are emerging in another animal beloved of developmental researchers: the tiny worm known as Caenorhabditis elegans.