BIANA Unification. Example where three different unification protocols are applied to three external databases (each external database is represented with a different color). BIANA network nodes are individual user entities. Each user entity consists of a set of equivalent external entities. Each external entity can belong to a single user entity, unless the database is defined as promiscuous database, where a single external entity can belong to multiple user entities. External entities in promiscuous databases can not form a user entity by themselves. In this theoretical example, in order to show the importance of the unification protocol, it can be observed Prot1A is merged with Prot1B when unifying by UniprotAccession identifier, while they are not merged if unification is done by Sequence and taxonomyID. However, when unified by UniprotAccession or geneSymbol, Prot1A, Prot1B, Prot2A and Prot2B are merged.