Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany. lee@molgen.mpg.de|Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany. lee@molgen.mpg.de|Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany. lee@molgen.mpg.de|Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany. lee@molgen.mpg.de