The Delft Bioinformatics Laboratory, Department of Intelligent Systems, Delft University of Technology, Delft, The Netherlands.|Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel.|Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel.|Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel.|The Delft Bioinformatics Laboratory, Department of Intelligent Systems, Delft University of Technology, Delft, The Netherlands.|Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel.