Department of Computational Biology and Applied Algorithmics, Max Planck Institute for Informatics, Saarbrxc3xbccken, Germany. altmann@mpi-inf.mpg.de|Department of Computational Biology and Applied Algorithmics, Max Planck Institute for Informatics, Saarbrxc3xbccken, Germany. altmann@mpi-inf.mpg.de|Department of Computational Biology and Applied Algorithmics, Max Planck Institute for Informatics, Saarbrxc3xbccken, Germany. altmann@mpi-inf.mpg.de|Department of Computational Biology and Applied Algorithmics, Max Planck Institute for Informatics, Saarbrxc3xbccken, Germany. altmann@mpi-inf.mpg.de