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Difference between revisions of "SW:BLAST"

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(benchmarks)
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simple BLAST+ command using the local shared blast nr database for protein query fasta file:
 
simple BLAST+ command using the local shared blast nr database for protein query fasta file:
  
   blastx -query my_protein_sequences.fasta -db /scratch/datasets/blast/nr -outfmt 10 -out my_protein_sequences_nr_blastout.csv
+
   blastx -query my_protein_sequences.fasta -db /scratch/data/bio/blast/nr -outfmt 10 -out my_protein_sequences_nr_blastout.csv
  
 
=== check database release ===
 
=== check database release ===
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<pre>
 
<pre>
 
   cores    memory    runtime hh:mm:ss
 
   cores    memory    runtime hh:mm:ss
     1      2GB      > 24 hours
+
     1       4GB     > 24 hours
 
     8      54GB      03:37:32
 
     8      54GB      03:37:32
 
   14      54GB      02:23:22
 
   14      54GB      02:23:22

Latest revision as of 10:09, 1 September 2021

BLAST & BLAST+

GCATemplates available: ada (blastx)

 module spider BLAST

or

 module spider BLAST+

example commands

simple BLAST+ command using the local shared blast nr database for protein query fasta file:

 blastx -query my_protein_sequences.fasta -db /scratch/data/bio/blast/nr -outfmt 10 -out my_protein_sequences_nr_blastout.csv

check database release

To check the downloaded version of the nr or nt database, load the latest version of BLAST+ and use the following command:

blastdbcmd -info -db /scratch/data/bio/blast/nr

v5 database

BLAST+ version 2.8.1 and newer supports the newest version 5 of the BLAST database which allows limiting a search by taxonomy.

The version 5 BLAST nr and nt databases and others are available in /scratch/data/bio/blast and used in the blast command like the following:

/scratch/data/bio/blast/nr
/scratch/data/bio/blast/nt

limit by taxonomy

Use -taxids to specify a taxonomy id:

blastn -query myseqs.fasta -taxids 33208 -db /scratch/data/bio/blast/nt -outfmt 5 -out blastout.xml -num_threads 8

If you get an error like "BLAST Database error: Taxonomy ID(s) not found.", it is most likely too high of a taxon level.

In order to get taxid list, which you can do on the command line prior to submitting a job, you need to load the EDirect module and a compatible BLAST+ module

EDirect/15.0.20210505-GCCcore-10.2.0
BLAST+/2.11.0-gompi-2020b

Then run the get_species_taxids.sh script and save the output to a file (33208.txids in this example)

get_species_taxids.sh -t 33208 > 33208.txids

Then use the -taxidlist option instead of -taxids in your job script

blastn -query myseqs.fasta -taxidlist 33208.txids -db /scratch/data/bio/blast/nt -outfmt 5 -out blastout.xml -num_threads 8

(you can also get the same subtree species taxid list from this webpage with 33208 used as an example): https://www.ncbi.nlm.nih.gov/taxonomy/?term=txid33208%5Bsubtree%5D

v4 database

BLAST version 4 databases (pre BLAST+ 2.8.1) such as nr and nt are not available right now.

benchmarks

The recommended number of cores to use with blast on Terra is all 28.

BLAST+ v2.11.0 blastx benchmarks for 25 nucleotide sequences vs nr on Terra

  cores    memory    runtime hh:mm:ss
    1       4GB      > 24 hours
    8      54GB      03:37:32
   14      54GB      02:23:22
   28      54GB      01:50:44