17. A non-transitory computer-readable medium including instructions that, when executed by a processing unit, cause the processing unit to extract pharmacogenomics relations from text, by performing the steps of: parsing a plurality of sentences into a plurality of parse trees; reducing the plurality of parse trees to include only parse trees of sentences where a plurality of seed terms occur within a same clause, wherein seed terms are identified from a lexicon comprising pharmacogenomics entities; transforming the reduced plurality of parse trees into a plurality of dependency graphs; identifying a plurality of entities from the plurality of seed terms for each dependency graph, said identifying comprising: identifying at least one modified entity by traversing a particular dependency graph of the plurality of dependency graphs in order to identify a core term modified by a seed term of the plurality of seed terms as the modified entity; and identifying seed terms from the particular dependency graph that do not modify a core term as key entities; identifying a plurality of relations between the identified plurality of entities from the plurality of dependency graphs, wherein each relation of the plurality of relations comprises at least first and second entities of the plurality of entities of a particular dependency graph and a relationship between the first and second entities that is identified by traversing edges within the particular dependency graph between the first and second entities to reach a same particular verb, wherein at least one of the first and second entities is a modified entity; constructing an ontology based on relative frequencies of the plurality of relations and of entities of the plurality of entities; normalizing the entities and the relationships within the identified plurality of relations according to the constructed ontology; and storing the normalized plurality of relations and normalized seed terms in a memory of at least one computer system.
17. A non-transitory computer-readable medium including instructions that, when executed by a processing unit, cause the processing unit to extract pharmacogenomics relations from text, by performing the steps of: parsing a plurality of sentences into a plurality of parse trees; reducing the plurality of parse trees to include only parse trees of sentences where a plurality of seed terms occur within a same clause, wherein seed terms are identified from a lexicon comprising pharmacogenomics entities; transforming the reduced plurality of parse trees into a plurality of dependency graphs; identifying a plurality of entities from the plurality of seed terms for each dependency graph, said identifying comprising: identifying at least one modified entity by traversing a particular dependency graph of the plurality of dependency graphs in order to identify a core term modified by a seed term of the plurality of seed terms as the modified entity; and identifying seed terms from the particular dependency graph that do not modify a core term as key entities; identifying a plurality of relations between the identified plurality of entities from the plurality of dependency graphs, wherein each relation of the plurality of relations comprises at least first and second entities of the plurality of entities of a particular dependency graph and a relationship between the first and second entities that is identified by traversing edges within the particular dependency graph between the first and second entities to reach a same particular verb, wherein at least one of the first and second entities is a modified entity; constructing an ontology based on relative frequencies of the plurality of relations and of entities of the plurality of entities; normalizing the entities and the relationships within the identified plurality of relations according to the constructed ontology; and storing the normalized plurality of relations and normalized seed terms in a memory of at least one computer system. 28. The non-transitory computer-readable medium of claim 17 , wherein key entities are genes, drugs, and phenotypes, and modified entities comprise a core term modified by at least one of a gene, a drug, and a phenotype.