1. Institute for Bioengineering, School of Engineering, University of Edinburgh, EdinburghEH9 3BF, U.K.
2. Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, EdinburghEH9 3BD, U.K.
3. School of Biological Sciences, University of Edinburgh, EdinburghEH9 3FF, U.K.
4. School of Natural and Environmental Sciences, Newcastle University, Newcastle upon TyneNE1 7RU, U.K.