1. P. Jarvis and C. Fankhauser, Plant Biology Laboratory, Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. L.-J. Chen and H.-m. Li, Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan. C. A. Peto, Laboratory of Neuronal Structure and Function, Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. J. Chory, Plant Biology Laboratory and Howard Hughes Medical Institute, Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.