Carl Gustav Carus Faculty of Medicine, Institute for Medical Informatics and Biometry (IMB), Technische Universität Dresden, Fetscherstr. 74, D-01307, Dresden, Germany. Contact:michael.seifert@tu-dresden.de.|Cellular Networks and Systems Biology, CECAD, University of Cologne, Joseph-Stelzmann-Str. 26, D-50931, Cologne, Germany.