Biological evaluation of the layout algorithms. The black and grey bars show the average semantic similarity over the networks of physical interactions (PI) and genetic interactions (GI), respectively. Error bars show the standard error of the mean (SEM). Only one of the GI networks could be laid out using the SEL algorithm in less than one hour. The performance of the other algorithms was compared against the multilevel layout with the clustering option on (MLL-C): *** p < 0.0005; ** p < 0.005; * p < 0.05, two-sided paired t-test.