Table 1.

Datasets used in the various approaches, their sizes and the appropriate citations.

Approach(es)	Source task(s)	Number of interactions	Citation for interactions data	Feature set
1. Homology based	Human-Salmonella known PPI Human-Salmonella predictions	62 190,868	Schleker et al., 2012* Kshirsagar et al., 2012	No feature set. Heuristics are used to infer interactions
2. T-SVM#	Human-Salmonella known PPI	62	Schleker et al., 2012*	(a) Protein sequence k-mers
				(b) Gene expression (from GEO)
				(c) GO term similarity
3. KMM†-SVM	Human-Salmonella known PPI	62	Schleker et al., 2012*
	Human-Francisella tularensis	1380
	Human-E.coli	32
	A. thaliana - Agrobact. tumefaciens	22	PHISTO*	Protein sequence k-mers
	A. thaliana - E. coli	15	(Tekir et al., 2012)
	A. thaliana - Pseudomonas syringae	13
	A. thaliana - Synechocyctis	23

^†KMM, Kernel Mean Matching;

^#SVM, Support Vector Machine; GO, Gene Ontology.

^*This source reports PPIs validated experimentally by biochemical and biophysical methods.