1. Department of Computer Science and Engineering, Yuan Ze University, Taoyuan 320, Taiwan, 2Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, 3Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, 4Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu 300, Taiwan and 5Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu 300, Taiwan