Center for Bioinformatics, Saarland University, 66041 Saarbruecken, Germany. yungki@bioinformatik.uni-saarland.de|Center for Bioinformatics, Saarland University, 66041 Saarbruecken, Germany. yungki@bioinformatik.uni-saarland.de|Center for Bioinformatics, Saarland University, 66041 Saarbruecken, Germany. yungki@bioinformatik.uni-saarland.de