1 Bioinformatics Institute (A∗STAR), 30 Biopolis Street, #07-01 Matrix, 138671 Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543 Singapore. Electronic address: peterjb@bii.a-star.edu.sg.
2 Bioinformatics Institute (A∗STAR), 30 Biopolis Street, #07-01 Matrix, 138671 Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543 Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore. Electronic address: chandra@bii.a-star.edu.sg.