Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.|Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.|Department of Biological Sciences and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, USA.|Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.