How are ACCESSION.VERSION identifiers managed?
The numerical .VERSION extension that frequently accompanies Accessions assigned by the NCBI/EBI/DDBJ collaboration is automatically included in the index created by xdformat. Version information can then used by xdget to identify the latest version of a sequence, when keyed by its Accession alone. Specific versions can also be retrieved if xdget is provided with an identifier of the form ACCESSION.VERSION (e.g., AAB33294.2). The N option of xdget can be used to report instead the first (-N0) or last (-Nn) instance of an Accession in the database; the A0 option can be used to report the lowest-numbered Version present in the database rather than the highest (the default or An). All instances of an accession will be reported by xdget if the ‑d option is specified. Indexing and retrieval can be restricted to Accessions assigned by the NCBI/EBI/DDBJ collaboration using the special option ‑Taccession (or ‑Tacc for short). Remember: Version numbers assigned by NCBI/EBI/DDBJ are only tied to
