Abstract
Will we ever be able to build predictive models of the complex genetic networks that determine function as well as malfunction of living cells? Studies of small cellular circuits that represent building blocks indicate that there might be a higher level of description that would reduce the vast complexity of genetic network models. In his Perspective, [Bornholdt][1] discusses the results reported in the same issue by [ Brandman et al .][2] who characterize a frequent building block of cellular circuits. Such elements exhibit particularly simple dynamics and the hope is that models of large genetic networks become feasible when based on the dynamics of such simple building blocks. [1]: http://www.sciencemag.org/cgi/content/full/310/5747/449 [2]: http://www.sciencemag.org/cgi/content/short/310/5747/496