Bioinformatics Institute, 30, Biopolis Street, #07-01, (S) 138671, Singapore. xiaoxing@bii.a-star.edu.sg|Bioinformatics Institute, 30, Biopolis Street, #07-01, (S) 138671, Singapore. xiaoxing@bii.a-star.edu.sg|Bioinformatics Institute, 30, Biopolis Street, #07-01, (S) 138671, Singapore. xiaoxing@bii.a-star.edu.sg