Finding old archived entries
Sequence Version Archive
In the section 'How sequence is assembled', we saw that sequence entries are subject to change, for instance when a sequence changes from being partially to fully assembled, or when annotation is added/changed for a sequence. The EMBL-Bank database, which contains the assembled sequences in ENA, only displays the most recent version of a sequence and its annotation. However, older versions of EMBL-Bank entries can still be accessed through the ENA Sequence Version Archive (SVA) (Figure 30) (5).
Figure 30. ENA Sequence Version Archive search for finding old versions of EMBL-Bank entries.
SVA results - querying an accession number
If you search on an EMBL-Bank accession number in the SVA, then you will get a list of all the version changes for that EMBL-Bank entry and the date they became public (Figure 31). You can select to view and/or save any of these versions. You can also cross-compare different versions to see exactly what has changed.
Figure 31. SVA search results displaying a list of all the versions of EMBL-Bank entry BN000065.
SVA results - comparing different versions of an entry
If you select to compare two or more versions of an EMBL-Bank entry, the SVA will display the full entry with everything that has been removed or inserted highlighted, so you can quickly see what changes have occurred (Figure 32).
Figure 32. SVA search results showing a comparision of two versions of EMBL-Bank entry BN000065 (14-NOV-2006 and 05-OCT-2004), where the lines inserted or removed are highlighted.