Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm S-171 21, Sweden; Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Haining 314400, China; Edinburgh Medical School, Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh EH1 1LT, UK.