Figure 1

Representation of annotations made using the core GO annotation model. Gene products can be annotated to several GO terms, and any GO term can be used to annotate any number of gene products, but the annotations remain independent. The stars indicate an annotation of a gene product to the GO term and each colour represents a single gene product. Using this simple GO annotation model, it is not clear from the annotations shown in which Cellular Component each of the protein activities are performed. For example, microsomal glutathione S-transferase 1 is represented by the red star and can perform two activities; glutathione transferase activity and glutathione peroxidase activity. It is found in three Cellular Components, the mitochondrion, endoplasmic reticulum and peroxisomal membrane, but from these annotations the knowledge that the glutathione transferase activity is performed in the mitochondrion [7] cannot be found. For clarity not all annotations of each gene product are shown nor all terms between the specified terms and the root node.