Computational Biology, Max Planck Institute f. Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany. utz.pape@molgen.mpg.de|Computational Biology, Max Planck Institute f. Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany. utz.pape@molgen.mpg.de|Computational Biology, Max Planck Institute f. Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany. utz.pape@molgen.mpg.de