As already mentioned, BLAST takes an input file with unknown sequences and aligns each such sequence against a database of known sequences. Therefore, to submit a BLAST job, you must specify which database you wish to align against. The first time you indicate a database for a BLAST job, CrocoBLAST will remember it and add it to its index, so that in the future it is easier for you to access this database. You can
provide a simple name for each database, that you may later refer to whenever you need to run a BLAST job. There are two ways to add a new database to the CrocoBLAST index.
==Retrieve from NCBI==
In the most typical scenario, you will use the [ftp://ftp.ncbi.nlm.nih.gov/refseq/release/ established reference sequence databases maintained by NCBI]. CrocoBLAST allows you to specify the name of such a database, and will download or update the database for you:
When adding or updating a database in this manner, you need not worry about the format of the database, as NCBI provides pre-formatted database files.
==Add from your computer==