Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA. liang.chen@usc.edu|Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA. liang.chen@usc.edu|Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA. liang.chen@usc.edu