Summary of the significant clusters obtained for several "Response to stress" GO classes. Significant clusters are indicated with black rectangles. Purity and coverage for the seven GO classes that generated positive results are indicated. As an example, the box shows the 7 positive clusters for the "Response to oxidative stress" GO class, which include 19 genes, all of them belonging to that class. The discovery of all these small significant clusters in a tree that contains 454 genes demonstrates the sensitivity of the method.