1. Center for Bioinformatics, Saarland University, Saarland Informatics Campus E2.1, Saarbrücken, Germany
2. Department of Computational Biology & Applied Algorithmics, Max Planck Institute for Informatics, Saarland Informatics Campus E1.4, Saarbrücken, Germany
3. Saarbrücken Graduate School of Computer Science, Saarland University, Saarbrücken, Germany
4. UC Santa Cruz Genomics Institute, University of California, Santa Cruz, CA, USA
5. Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
6. Department of Genetics, University of Cambridge, Cambridge, UK