1. David R. Cheriton School of Computer Science, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
2. Program in Cell Biology and SPARC BioCentre, Hospital for Sick Children, 686 Bay Street, Toronto, Ontario M5G 0A4, Canada
3. Rapid Novor Inc., Unit 450, 137 Glasgow Street, Kitchener, Ontario N2G 4X8, Canada
4. Department of Molecular Genetics, University of Toronto, 686 Bay Street, Toronto, Ontario M5G 0A4, Canada