He obtained his Ph.D. at the University of Zurich in 1965 and after two years as a research assistant of Professor Ernst Hadorn he joined Professor Alan Garen 's group at Yale University in New Haven as a postdoctoral fellow .
He earned his Ph.D. at the University of Zurich in 1965 . After two years as a research assistant of Professor Ernst Hadorn he joined Professor Alan Garen 's group at Yale University in New Haven as a postdoctoral fellow .