Center for Bioinformatics, University of Tübingen, Tübingen 72076, Germany Department of Computer Science, Applied Bioinformatics, Tübingen 72076, Germany Quantitative Biology Center, Tübingen 72076, Germany Faculty of Medicine, University of Tübingen, Tübingen 72076, Germany Max Planck Institute for Developmental Biology, Biomolecular Interactions, Tübingen 72076, Germany.