1 Department of Biosystems Science and Engineering, ETH Zürich, Zürich, Basel 4058, Switzerland; SIB Swiss Institute of Bioinformatics, Switzerland.
2 Department of Biosystems Science and Engineering, ETH Zürich, Zürich, Basel 4058, Switzerland; SIB Swiss Institute of Bioinformatics, Switzerland. Electronic address: karsten.borgwardt@bsse.ethz.ch.