| NCBI BLAST FTP Site | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Tao Tao, Ph.D. User Service NCBI, NLM, NIH | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| 1. Introduction | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| NCBI BLAST ftp site (ftp.ncbi.nlm.nih.gov) provides software packages for standalone blast, client server blast, and wwwblast packages for various platforms. It also provides commonly used blast databases in preformatted as well as FASTA format. Documents on the blast executables and other related subjects are also available from this site. This file describes the the subdirectories and files found on this ftp site. It also prvoides the basic information on file content and on how the files should be used. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 2. File list and content | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| This section list and describes the files found on the BLAST FTP site. File content for each directory/subdirectory is described in a separate table. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 2.1 ftp.ncbi.nlm.nih.gov/blast/ general directory content | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The blast ftp directory contains several subdirectories each for a specific set of files.
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| 2.2 /blast/db/ directory content | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Databases larger than two gigabytes (2 GB) are formatted in multiple
volumes, which are named using the "database.##.tar.gz" convention.
All relevant volumes are required. An alias file is provided so that
the database can be called using the alias name without the extension
(.nal or .pal). For example, to call est database, simply use "–d est"
option in the commandline (without the quotes).
Certain databases are subsets of a larger parental database. For those
databases, mask files, rather than actual databases, are provided. The
mask file needs the parent database to function properly. The parent
databases should be generated on the same day as the mask file. For
example, to use swissprot preformatted database, swissprot.tar.gz, one
will need to get the nr.tar.gz with the same date stamp.
To use the preformatted blast database file, first inflate the file
using gzip (unix, linux), WinZip (window), or StuffIt Expander (Mac),
then extract the component files out from the resulting tar file using
tar (unix, linux), WinZip (Window), or StuffIt Expander (Mac). The
resulting files are ready for BLAST.
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| 2.2.1 /blast/db/FASTA/ subdirectory content | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The FASTA database files are now stored in this subdirectory, it does
contain some additional databases that are not available via the NCBI
BLAST pages. Due to file size issues, the full est database is not
provided. One needs to get the three subsets and concatenate them
together to get the complete est database.
These databases will need to be formatted using formatdb program found
in the standalone blast executable package. The recommended
commandlines to use are:
formatdb –i input_db –p F –o T for nucleotideFor additional information on formatdb, please see the formatdb.html at: /blast/documents/formatdb.html
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| 2.3 File content for /blast/demo/ directory | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| This directory contains some technical presentt-family: co gb|accession|locus EMBL Data Library emb|accession|locus DDBJ, DNA Database of Japan dbj|accession|locus NBRF PIR pir||entry Protein Research Foundation prf||name SWISS-PROT sp|accession|entry name Brookhaven Protein Data Bank pdb|entry|chain Patents pat|country|number GenInfo Backbone Id bbs|number General database identifier gnl|database|identifier NCBI Reference Sequence ref|accession|locus Local Sequence identifier lcl|identifier "gi" identifiers are being assigned by NCBI for all sequences contained within NCBI's sequence databases. The "gi" identifier provides a uniform and stable naming convention whereby a specific sequence is assigned its unique gi identifier. If a nucleotide or protein sequence changes, however, a new gi identifier is assigned, even if the accession number of the record remains unchanged. Thus gi identifiers provide a mechanism for identifying the exact sequence that was used or retrieved in a given search. We recommend that "gi display option" be activated in local blast search by setting the -I option to T, which was set to false by default: -I Show GI's in deflines [T/F] default = F For databases whose entries are not from official NCBI sequence databases, such as Trace database, the gnl| convention is used. For custom database, this convention should be followed and the id for each sequence must be unique, if one would like to take the advantage of indexed database, which enables specific sequence retrieval using fastacmd program included in the blast executable package. One should refer to documents distributed in the standalone BLAST package for more details. 6. Formatting the FASTA database FASTA database files need to be formatted with formatdb before they can be used in local blast search. For those from NCBI, the following formatdb are recommended: formatdb -i input_db -p F -o T for nucleotide formatdb -i input_db -p T -o T for protein The -A option introduced in 2.2.3 is now built into the formatdb program and thus removed from the list of configurable options since 2.2.8. This enables formatdb to properly handle large sequence files (longer than 16 million bases). Please refer to formatdb.html under the /blast/documents directory for more information. Databases prepared using 2.2.8 formatdb will not be backward compatible with blast programs old than version 2.2.3. 7. Technical Support Questions and comments on this document and NCBI BLAST related questions should be sent to blast-help group at: blast-help@ncbi.nlm.nih.gov For information about other NCBI resources/services, please send email to NCBI User Service at: info@ncbi.nlm.nih.gov $Header: /src/NCBI/vault.ncbi/distrib/doc/blast/blastdb.html,v 1.10 2008/10/02 16:01:03 camacho Exp $ | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||