We analyze the perturbation of the expression levels of thousands of genes when one of them is knocked-out, by measuring avalanches, the number of genes whose expression is affected in a knock-out experiment, and gene susceptibilities, which measure how often the expression of a given gene is modified. Experimental data concerning the yeast S. cerevisiae are available. Knock-out is simulated, using random boolean network models of gene regulation, in several experiments, using different sets of boolean functions. The major results (when only canalizing functions are allowed) are that the distributions of avalanches and susceptibilities are very similar in different synthetic networks, with very small variance, and that these two distributions closely resemble the experimental ones (a result which is even more surprising since no parameter optimization has been performed). These results strongly suggest that the distribution of avalanches and susceptibilities may be generic properties, common to many different genetic networks.
['Roberto Serra', 'Marco Villani', 'Alessandro Semeria']
Robustness to Damage of Biological and Synthetic Networks