1. Center for Bioinformatics, Saarland University, Saarland Informatics Campus E2.1, Saarbrücken, 66123, Germany
2. Max Planck Institute for Informatics, Saarland Informatics Campus E1.4, Saarbrücken, Germany
3. Graduate School of Computer Science, Saarland University, Saarland Informatics Campus E1.3, Saarbrücken, Germany
4. European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany
5. Department of Genome Sciences, University of Washington, Seattle, WA, USA
6. Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA