Author details Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA. Department of Biostatistics, Harvard TH Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA. Functional Genomics Group, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA. Bioinformatics and Genomics Programme Centre for Genomic Regulation (CRG) and UPF, Doctor Aiguader, 88, Barcelona 08003, Spain. Department of Genetics and Genome Sciences, Institute for System Genomics, UConn Health Center, Farmington, CT 06030, USA. Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, USA. Department of Genetics, Stanford University, 300 Pasteur Drive, MC-5477, Stanford, CA 94305, USA. School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.