A gene that builds bigger brains, called beta-catenin, was discovered in the laboratory of Christopher A. Walsh, Bullard Professor of Neurology at Harvard Medical School. Researchers there engineered increased activity into the beta-catenin gene in mice, and the mice brains grew to almost twice the usual size. Not only that, but the cerebral cortex, seat of intelligence and language, became more humanlike. Walsh and his colleagues, working with C. Geoffrey Woods at St. James University Hospital in Leeds, England, also identified a gene known as ASPM, mutations of which are a major cause of inherited microcephaly. Finding ASPM opens the way to genetic counseling and prenatal diagnoses for families at high risk for the disease. (Microcephaly is more prevalent in Asian nations from Jordan to India, where arranged marriages between relatives are common.)