Computational Molecular Biology, Max Planck Institute for Molecular Genetics Ihnestrasse 63-73, D-14195, Berlin, Germany. bais@molgen.mpg.de|Computational Molecular Biology, Max Planck Institute for Molecular Genetics Ihnestrasse 63-73, D-14195, Berlin, Germany. bais@molgen.mpg.de|Computational Molecular Biology, Max Planck Institute for Molecular Genetics Ihnestrasse 63-73, D-14195, Berlin, Germany. bais@molgen.mpg.de