1Institute for Molecular Biotechnology, Biology VII, RWTH Aachen, Worringerweg 1, D-52074 Aachen, Germany
2Department of Biology, University of York, Heslington, York YO10 5DD, UK
3Fraunhofer Institute for Molecular Biology and Applied Ecology, IME, Grafschaft, Auf dem Aberg 1, 57392 Schmallenberg, Germany