Researchers are beginning to understand how a gene called “stardust” works to set up the basic top-down architecture of the epithelial cells that line the gut, skin, and many other organs of an embryo. Working with Norbert Perrimon, Harvard Medical School (HMS) professor of genetics, Beth Stronach, HMS research fellow in genetics, has cloned the stardust gene. The two are working to understand the gene with colleagues at the University of California, San Francisco. Their discoveries, reported in the Dec. 6, 2001, issue of the journal Nature, could help researchers answer some of the fundamental questions of biology: How do cells send and receive signals? How do tissues and organs take shape? They could also hold clues to ongoing mysteries such as how cancers arise.