1. Department of Computer Science and Engineering, University of California, Riverside, CA 92521, USA
2. Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
3. Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
4. Bioinformatics Division, BNRIST, Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China