The Predicted Genomic Islands database (Pre_GI) is a comprehensive repository of prokaryotic
genomic islands (islands, GIs) freely accessible at http://pregi.bi.up.ac.za/index.
php. Pre_GI, Version 2015, catalogues 26 744 islands identified in 2407 bacterial/archaeal
chromosomes and plasmids. It provides an easy-to-use interface which allows users the
ability to query against the database with a variety of fields, parameters and associations.
Pre_GI is constructed to be a web-resource for the analysis of ontological roads between
islands and cartographic analysis of the global fluxes of mobile genetic elements through
bacterial and archaeal taxonomic borders. Comparison of newly identified islands
against Pre_GI presents an alternative avenue to identify their ontology, origin and
relative time of acquisition. Pre_GI aims to aid research on horizontal transfer events and
materials through providing data and tools for holistic investigation of migration of
genes through ecological niches and taxonomic boundaries.