1. The Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine , Hannoversche Str. 28, 10115 Berlin, Germany
2. Department of Computer Science, Faculty of Mathematics and Natural Sciences , Humboldt Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
3. Department of Computer Science, Faculty of Science, University of Tübingen , 72074 Tübingen, Germany
4. Department of Biology, Faculty of Life Sciences , Humboldt Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany