Vertebrate Genomics-Bioinformatics Group, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany. hache@molgen.mpg.de|Vertebrate Genomics-Bioinformatics Group, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany. hache@molgen.mpg.de|Vertebrate Genomics-Bioinformatics Group, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany. hache@molgen.mpg.de|Vertebrate Genomics-Bioinformatics Group, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany. hache@molgen.mpg.de