Center for Bioinformatics (ZBIT), Tübingen University, Sand 14, 72076 Tübingen, Germany. scornava@informatik.uni-tuebingen.de|Center for Bioinformatics (ZBIT), Tübingen University, Sand 14, 72076 Tübingen, Germany. scornava@informatik.uni-tuebingen.de|Center for Bioinformatics (ZBIT), Tübingen University, Sand 14, 72076 Tübingen, Germany. scornava@informatik.uni-tuebingen.de