NRW International Graduate School in Bioinformatics and Genome Research, Bielefeld University, Postfach 10 01 31, D-33501 Bielefeld, Germany. askusa@cebitec.uni-bielefeld.de|NRW International Graduate School in Bioinformatics and Genome Research, Bielefeld University, Postfach 10 01 31, D-33501 Bielefeld, Germany. askusa@cebitec.uni-bielefeld.de|NRW International Graduate School in Bioinformatics and Genome Research, Bielefeld University, Postfach 10 01 31, D-33501 Bielefeld, Germany. askusa@cebitec.uni-bielefeld.de