Genes that are consistently part of the same operon across different, distantly related genomes are likely to be part of the same protein complex or functional process across all species.

The yeast two-hybrid method allows the mapping of binary or pair-wise interactions, protein chips are suited to detect protein–protein, pro- tein–lipid and other protein–ligand interactions.

Topics include: Protein – Protein Interactions, Structural Analyses of Domain Interactions, & The Use of Gene Order & Phylogeny to Predict Protein – Protein Interactions.