Interdisciplinary Centre for Bioinformatics, Universität Leipzig, D-4107 Leipzig, Haertelstr 16-18, Germany. binder@izbi.uni-leipzig.de|Interdisciplinary Centre for Bioinformatics, Universität Leipzig, D-4107 Leipzig, Haertelstr 16-18, Germany. binder@izbi.uni-leipzig.de|Interdisciplinary Centre for Bioinformatics, Universität Leipzig, D-4107 Leipzig, Haertelstr 16-18, Germany. binder@izbi.uni-leipzig.de