mylinuxnotes

Wednesday 20070919

howto BLAST

Filed under: bioinformatics, blast, howto — jeff @ 3:11 pm

In ubuntu, the BLAST package is called blast2

sudo aptitude install blast2

This installs a whole bunch of blast commands for local and remote searching.  For example, you can search NCBI with a list of fasta entries as queries (sequentially) using the remote NCBI server to do the work:

blastcl3 -p blastp -m 3 -v 10 -b 10 -i infile.fasta -o outfile.txt

Where, here I’m just looking for a few quick top hits.  -p is the important option, where you define the search engine.  In this example I’m using blastp to search protein.  I think the default database is ncbi nr.

And here’s an example of searching a local database using your own cpu:

blast2 -p blastp -m 3 -v 10 -b 10 -i infile.fasta

and an outfile isn’t defined, so it just goes to standard out, ready for pipes.

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