Program in Computational Biology and Bioinformatics, University of Southern California, 1050 Childs Way, Los Angeles, CA 90089-2910, USA.|Program in Computational Biology and Bioinformatics, University of Southern California, 1050 Childs Way, Los Angeles, CA 90089-2910, USA.|Program in Computational Biology and Bioinformatics, University of Southern California, 1050 Childs Way, Los Angeles, CA 90089-2910, USA.