Figure 3

Illustration of the refinement algorithm. (a) Before the refinement, four groups are labelled significant (red) that contain the genes 1–4. (b) On the deepest level of the tree significant categories remain significant (orange). On the next level a significant category (arrow) is tested after all genes in the significant descendant categories (blue box) are removed. In this example, the category remains significant. (c) This procedure is repeated for the category on the next level (arrow) and again all genes in significant descendant categories (blue box) are removed. In this example the category is no longer significant after refinement.