Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Department of Bioinformatics, Schloss Birlinghoven, 53754 Sankt Augustin, Germany. thomas@informatik.hu-berlin.de|Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Department of Bioinformatics, Schloss Birlinghoven, 53754 Sankt Augustin, Germany. thomas@informatik.hu-berlin.de|Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Department of Bioinformatics, Schloss Birlinghoven, 53754 Sankt Augustin, Germany. thomas@informatik.hu-berlin.de|Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Department of Bioinformatics, Schloss Birlinghoven, 53754 Sankt Augustin, Germany. thomas@informatik.hu-berlin.de|Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Department of Bioinformatics, Schloss Birlinghoven, 53754 Sankt Augustin, Germany. thomas@informatik.hu-berlin.de