1. Developmental Unit, European Molecular Biological Laboratory (EMBL), Meyerhofstraße 1, D-69117 Heidelberg, Germany.
2. Computational Unit, European Molecular Biological Laboratory (EMBL), Meyerhofstraße 1, D-69117 Heidelberg, Germany.
3. Genomics Core Facility, European Molecular Biological Laboratory (EMBL), Meyerhofstraße 1, D-69117 Heidelberg, Germany.
4. Children's Hospital, Oakland Research Institute, 747 52nd Street, Oakland, CA 94609, USA.
5. Génoscope, Centre National de Séquençage and CNRS UMR 8030, 2 Rue Gaston Crémieux, CP 5706 91057 Evry Cedex, France.