Gene Ontology biological process categories associated with the five genes selected, but not present in reference databases, as related to Parkinson's disease. Boxes in dark purple represent the most specific biological process categories the selected five genes have been annotated with (associated gene symbol above the box). Because of inheritance in the Gene Ontology hierarchy, genes are also annotated with all parent categories. Boxes in light green denote dopamine biological process categories that are direct child or sibling of two of the most specific biological process categories associated with two of the selected five genes. Note that motor symptoms in Parkinson's disease are generally thought to result from deficiency or dysfunction of dopamine or dopaminergic neurons in the substantia nigra . Box category links in dark black represent IS-A relations, whereas those in light red represent PART_OF.