Table 1.

List of dependency features

Features	Description
Relationship term	Root of the portion of the dependency tree connecting phenotype and genotype
Stemmed relationship term	Stemmed by Mallet
Relative position of relationship term	Whether it is before the first entity, after the second entity or between them
The relationship term combined with the dependency relationship	To consider the grammatical role of the relationship term in the dependency path.
The relationship term and its relative position
Key term	Described in Ibn Faiz’s four step method [48]
Key term and its relative position
Collapsed version of the dependency path	All occurrences of nsubj/nsubjpass are replaced with subj, rcmod/partmod with mod, prep x with x and everything else with O, a placeholder to indicate that a dependency has been ignored.
Second version of the collapsed dependency path	Only the prep_* of dependency relationships are kept.
Negative dependency relationship	A binary feature that shows whether there is any node in the path between the entities which dominates a neg dependency relationship. This feature is used to catch the negative relationships.
prep_between	A binary feature that checks for the existence of two consecutive prep_between links in a dependency path.