Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA. grey@bioeng.ucsd.edu
A recent study in Nature (Isalan et al., 2008) has examined the effects of systematically adding new transcriptional interactions in the bacterium Escherichia coli. Surprisingly, the majority of the engineered connections have no effect on growth, and in some cases the new connections enhance fitness. These findings reveal insights into the robustness and evolvability of gene networks.