Center for Bioinformatics ZBIT, Sand 14, Tübingen, University of Tübingen, Germany. auch@informatik.uni-tuebingen.de|Center for Bioinformatics ZBIT, Sand 14, Tübingen, University of Tübingen, Germany. auch@informatik.uni-tuebingen.de|Center for Bioinformatics ZBIT, Sand 14, Tübingen, University of Tübingen, Germany. auch@informatik.uni-tuebingen.de|Center for Bioinformatics ZBIT, Sand 14, Tübingen, University of Tübingen, Germany. auch@informatik.uni-tuebingen.de