MOE Key Laboratory of Bioinformatics, Beijing National Research Center for Information Science and Technology, Department of Automation, Tsinghua University, Beijing, China.|CEMS, NCMIS, MDIS, Academy of Mathematics and Systems Science, National Center for Mathematics and Interdisciplinary Sciences, Chinese Academy of Sciences, Beijing, China.|MOE Key Laboratory of Bioinformatics, Beijing National Research Center for Information Science and Technology, Department of Automation, Tsinghua University, Beijing, China.