1. Max-Delbruck-Center for Molecular Medicine (MDC), Robert-Rossle-Str. 10, 13092 Berlin-Buch, Germany.
2. MWG, Anzinger Strasse 7a, 85560 Ebersberg, Germany.
3. Max-Planck-Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany.
4. The Institute for Genomic Research, Rockville, MD 20850, USA.
5. MRC Functional Genetics Unit, Department of Human Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.