Computer Science Department, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA, Department of Computer Science, Georgia State University, Atlanta, GA, 30303 and Department of Human Genetics, University of California, Los Angeles, CA 90095, USAComputer Science Department, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA, Department of Computer Science, Georgia State University, Atlanta, GA, 30303 and Department of Human Genetics, University of California, Los Angeles, CA 90095, USA.