1. Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany;
2. Institute of Functional Epigenetics (IFE) and Institute of Computational Biology (ICB), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
3. Faculty of Biology, Ludwig-Maximilians Universität, D-82152 Planegg-Martinsried, Germany