Annotation components utilized by VSGdb. The rectangles represent the primary tags which define parts of a VSG (CDS defines an entire VSG). The ovals represent features of each primary tag. Secondary annotation was carried out to link the systematic_ ID, domain_combo and product features of each VSG to all of its components. These features are used in the sequence retrieval (as FASTA or as a database for BLAST). All features are used in the construction of individual VSG pages. Features containing curation and comments are used in the text search.