Systems Biology Group, Bioinformatics Institute, Singapore. andrewg@bii-sg.org|Systems Biology Group, Bioinformatics Institute, Singapore. andrewg@bii-sg.org|Systems Biology Group, Bioinformatics Institute, Singapore. andrewg@bii-sg.org|Systems Biology Group, Bioinformatics Institute, Singapore. andrewg@bii-sg.org|Systems Biology Group, Bioinformatics Institute, Singapore. andrewg@bii-sg.org|Systems Biology Group, Bioinformatics Institute, Singapore. andrewg@bii-sg.org