The Advanced Computational Modelling Centre and the ARC Centre in Bioinformatics, The University of Queensland, Brisbane 4072, Australia. kb@maths.uq.edu.au|The Advanced Computational Modelling Centre and the ARC Centre in Bioinformatics, The University of Queensland, Brisbane 4072, Australia. kb@maths.uq.edu.au|The Advanced Computational Modelling Centre and the ARC Centre in Bioinformatics, The University of Queensland, Brisbane 4072, Australia. kb@maths.uq.edu.au|The Advanced Computational Modelling Centre and the ARC Centre in Bioinformatics, The University of Queensland, Brisbane 4072, Australia. kb@maths.uq.edu.au