International Graduate School in Bioinformatics and Genome Research, University of Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany. burkhard@TechFak.Uni-Bielefeld.DE|International Graduate School in Bioinformatics and Genome Research, University of Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany. burkhard@TechFak.Uni-Bielefeld.DE|International Graduate School in Bioinformatics and Genome Research, University of Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany. burkhard@TechFak.Uni-Bielefeld.DE|International Graduate School in Bioinformatics and Genome Research, University of Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany. burkhard@TechFak.Uni-Bielefeld.DE