1. MOE Key Laboratory of Bioinformatics and Bioinformatics Division, TNLIST, Tsinghua University, Beijing, China
2. Department of Computer Science and Technology, State Key Lab of Intelligent Technology and Systems, Tsinghua University, Beijing, China
3. Department of Automation, Tsinghua University, Beijing, China
4. Program in Computational Biology and Bioinformatics, University of Southern California, CA, USA