Department of Life Sciences, Imperial College, London, United Kingdom, Centre for Integrative Systems Biology and Bioinformatics, Imperial College, London, United Kingdom.|Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America.|Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America.|Department of Life Sciences, Imperial College, London, United Kingdom, Centre for Integrative Systems Biology and Bioinformatics, Imperial College, London, United Kingdom.