Center for Bioinformatics, University of Hamburg, Bundesstrasse 43, Hamburg 20146, Germany. beckstette@zbh.uni-hamburg.de.|Center for Bioinformatics, University of Hamburg, Bundesstrasse 43, Hamburg 20146, Germany. beckstette@zbh.uni-hamburg.de.|Center for Bioinformatics, University of Hamburg, Bundesstrasse 43, Hamburg 20146, Germany. beckstette@zbh.uni-hamburg.de.