1. Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
2. Current Affiliation: Institute of Molecular Biology, Academia Sinica, Nangang District, Taipei 115, Taiwan
3. Current Affiliation: Perfect Day, Inc., Emeryville, California 94608, USA
4. Current Affiliation: Institut Européen de Chimie et Biologie, 33600 Pessac, France
5. Current Affiliation: Department of Genetics, Stanford University School of Medicine, Stanford, California 94305, USA
6. Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA