We would like to thank Jan Weyer-Menkhoff, Isabelle Schneider, Rasmus Steinkamp and Amarendran Subramanian for their support in the software development and evaluation and Peter Meinicke for critically reading the manuscript. The work was supported by DFG grant MO 1048/1-1 to BM, by BMBF grant 01AK803G (Medigrid) to BM and by DFG Bioinformatics Initiative BIZ-6/1-2 to SJP and PFS.