Bioinformatics Division, TNLIST and Department of Automation, Tsinghua University, Beijing 100084, China. shaoli@mail.tsinghua.edu.cn|Bioinformatics Division, TNLIST and Department of Automation, Tsinghua University, Beijing 100084, China. shaoli@mail.tsinghua.edu.cn|Bioinformatics Division, TNLIST and Department of Automation, Tsinghua University, Beijing 100084, China. shaoli@mail.tsinghua.edu.cn