Since the FB2015_01 release, the gene model annotations shown in FlyBase for Drosophila virilis are based on a Gnomon gene prediction set provided by the NCBI (see FBrf0224144). For each version of the gene prediction set, there may be a number of changes that affect the total number of gene models (annotations). FlyBase adds comments indicating the nature of the change in each of the affected gene reports, attributed to this "FlyBase analysis" reference.

For each genome release, there are generally a number of changes that affect the total number or type of gene models (annotations) for that annotated genome. A summary of these changes can be found in the "Summary of changes from previous release" section of the relevant genome release on the "Release Notes" page. Specific notes concerning major changes are noted in the appropriate gene records and are attributed to a reference for that genome annotation release. This particular reference is the "FlyBase analysis" reference for release 1.03 of the annotated D.virilis genome; these gene model annotations are based on a Gnomon gene prediction set provided by the NCBI (see FBlc0000666).