Ever since Adam and Eve came together in the Garden of Eden, humankind has pondered the mystery of the sexes. Now, science seems finally to have found la difference--a stretch of DNA with the decidedly unromantic name of Sry, for sex-determining region of the Y chromosome. During the past several years, researchers came to suspect that this piece of DNA was the fabled "male" gene, or testes-determining factor, which triggers a cascade of changes that adds male parts to the basically female mammalian body plan. And now, British government scientists may have proof that the gene behaves as advertised.
In a conceptually simple experiment reported in the British journal Nature, Robin Lovell-Badge and co-workers at England's National Institute for Medical Research added the Sry gene to female mouse embryos. When the embryos developed into mice, some looked and behaved like males. The problem was, the transformation took place in only three of 11 mice tested. The next step: figuring out exactly what triggers the gene--and how it does its profound work.