The above example Web Application uses a portlet engine to display information from a variety of repositories (and other data sources). The aggregation system can be used to pull together information from different sources. It can be used directly to index and then extract subsets of information from larger data files. The above example web application is a prototype application which uses our adaptive data management system to store information about gene annotations, ChIP-Chip experiments, transcription factor binding site predications and gene expression studies. The Gene Expression Portlet transparently accesses and extracts subsets of information from data files by simply querying the aggregation system by gene name.