Large-scale species comparisons at genome and expressed sequence tag (EST) levels have revealed that early branching metazoans such as sponges and cnidarians share many if not most of their genes with the allegedly advanced vertebrates including man. The ancestor of all animals may thus have been much more complex than anticipated. To facilitate and support analysis of genomic and transcriptomic resources in early branching metazoans, we have established a local bio-computational platform, Compagen (http://www.compagen.org). The platform contains searchable databases with selected raw genomic and EST sequence datasets from sponges and cnidarians up to the lower vertebrates. In addition to the public datasets, Compagen also provides processed data like CAP3 assembled ESTs or predicted peptides. Evaluating the efficacy of the platform by screening for genes reported to be essential in controlling stem-cell behavior in higher organisms uncovered ancient origins for some but not all components of the vertebrate stem-cell system.