Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, 117456, Singapore. xiechaos@gmail.com.|Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, 117456, Singapore.|Centre for Bioinformatics, Tuebingen University, Tuebingen, 72076, Germany.|Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, 117456, Singapore.|Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, 117456, Singapore.