NCBI is transitioning to Accession-Based BLAST in stages. As of January 2019, we have converted some* of the most popular traditional (GI-based) BLAST databases into accession-based format. If you are a BLAST+ (command-line tools) user and you want to benefit from the new system, you will need to (1) access Accession-Based BLAST databases and (2) use BLAST+ version 2.8.0 or newer:
1. You can access the Accession-Based BLAST databases in two ways:
- via update_blastdb.pl by using the
–blastdb_versionoption (see the Get NCBI BLAST databases document and a separate article on update_blastdb.pl )
- blast/db/v5/ directory
For general guidelines on using BLAST+ command line tools, refer to the BLAST® Command Line Applications User Manual. Check the PDF document for specific enhancements that we introduced with the Accession-Based BLAST, including new ways of limiting searches by taxonomy.
*Please let us know (write to firstname.lastname@example.org ) if you need a specific BLAST database and we will do our best to provide it for you.