1. School of Life Science and Technology; Tokyo Institute of Technology; 4259 Nagatsuta-cho, Midori-ku Yokohama Kanagawa 226-8501 Japan
2. Department of Bioinformatic Engineering; Graduate School of Information Science and Technology; Osaka University; 1-5 Yamadaoka Suita Osaka 565-0871 Japan
3. Quantitative Biology Center; RIKEN; Suita Osaka 565-0874 Japan
4. Universal Biology Institute; The University of Tokyo; Tokyo 113-0033 Japan