School of Biological Sciences and Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK. tambis@cs.man.ac.uk|School of Biological Sciences and Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK. tambis@cs.man.ac.uk|School of Biological Sciences and Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK. tambis@cs.man.ac.uk|School of Biological Sciences and Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK. tambis@cs.man.ac.uk|School of Biological Sciences and Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK. tambis@cs.man.ac.uk|School of Biological Sciences and Department of Computer Science, University of Manchester, Oxford Road, Manchester M13 9PT, UK. tambis@cs.man.ac.uk