A gene discovered by Harvard researchers and their colleagues in England makes a protein necessary to trigger a hormonal cascade that flows from the brain to the gonads. Without it, the researchers have shown, humans and mice do not become sexually mature. Stephanie Seminara, an assistant professor of medicine at Harvard Medical School, called the gene part of “the pilot light of puberty.” Seminara and other Harvard investigators searched for the gene for many years before identifying it in a Saudi family. Mutations in the gene have prevented many members of that family from undergoing puberty. In August, Seminara received a phone call from Paradigm Therapeutics, a biotech company in Cambridge, England, saying that the company had created a mouse that failed to reach puberty. Paradigm Therapeutics has a tradition of naming its gene discoveries after famous orphans, because their function is unknown. The nonpubertal gene was christened Harry Potter after the popular boy wizard. A report appeared in the Oct. 23, 2003 issue of The New England Journal of Medicine.