Output user interface of the GOTM The GOTree window displays the expandable tree structure of the GO categories. Each GO category is followed by three parameters: O (Observed gene number in the category); E (Expected gene number in the category) and R (Ratio of enrichment for the category). The fourth parameter P (p value calculated from the hypergeometric test) is given for the categories with R > 1 to indicate the significance of enrichment. Categories with P < 0.01 are colored red. The gene/category list window displays genes in selected GO categories ("eye morphogenesis" in this case) and the names of enriched GO categories followed by the parameters O, E, R and P. The genes are represented by LocusIDs followed by gene symbols and ratios in the microarray experiment. The gene information window displays the gene information record for the selected gene.