Manpage of fasta36/ssearch36/[t]fast[x,y]36/lalign36
Section: User Commands (1)
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fasta36 - scan a protein or DNA sequence library for similar
fastx36 - compare a DNA sequence to a protein sequence
database, comparing the translated DNA sequence in forward and
tfastx36 - compare a protein sequence to a DNA sequence
database, calculating similarities with frameshifts to the forward and
fasty36 - compare a DNA sequence to a protein sequence
database, comparing the translated DNA sequence in forward and reverse
tfasty36 - compare a protein sequence to a DNA sequence
database, calculating similarities with frameshifts to the forward and
fasts36 - compare unordered peptides to a protein sequence database
fastm36 - compare ordered peptides (or short DNA sequences)
to a protein (DNA) sequence database
tfasts36 - compare unordered peptides to a translated DNA
fastf36 - compare mixed peptides to a protein sequence database
tfastf36 - compare mixed peptides to a translated DNA
ssearch36 - compare a protein or DNA sequence to a
sequence database using the Smith-Waterman algorithm.
ggsearch36 - compare a protein or DNA sequence to a
sequence database using a global alignment (Needleman-Wunsch)
glsearch36 - compare a protein or DNA sequence to a
sequence database with alignments that are global in the query and
local in the database sequence (global-local).
lalign36 - produce multiple non-overlapping alignments for protein
and DNA sequences using the Huang and Miller sim algorithm for the
prss36, prfx36 - discontinued; all the FASTA programs will estimate
statistical significance using 500 shuffled sequence scores if two
sequences are compared.
Release 3.6 of the FASTA package provides a modular set of sequence
comparison programs that can run on conventional single processor
computers or in parallel on multiprocessor computers. More than a
dozen programs - fasta36, fastx36/tfastx36, fasty36/tfasty36,
fasts36/tfasts36, fastm36, fastf36/tfastf36, ssearch36, ggsearch36,
and glsearch36 - are currently available.
All the comparison programs share a set of basic command line options;
additional options are available for individual comparison functions.
Threaded versions of the FASTA programs (built by default under
Unix/Linux/MacOX) run in parallel on modern Linux and Unix multi-core
or multi-processor computers. Accelerated versions of the
Smith-Waterman algorithm are available for architectures with the
Intel SSE2 or Altivec PowerPC architectures, which can speed-up
Smith-Waterman calculations 10 - 20-fold.
In addition to the serial and threaded versions of the FASTA programs,
MPI parallel versions are available as fasta36_mpi,
ssearch36_mpi, fastx36_mpi, etc. The MPI parallel versions
use the same command line options as the serial and threaded versions.
Running the FASTA programs
By default, the FASTA programs are no longer interactive; they are run
from the command line by specifying the program, query.file, and
library.file. Program options must preceed the
query.file and library.file arguments:
fasta36 -option1 -option2 -option3 query.file library.file > fasta.output
The "classic" interactive mode, which prompts for a query.file and
library.file, is available with the -I option. Typing a program
name without any arguments (ssearch36) provides a short help
message; program_name -help provides a complete set of program
Program options MUST preceed the query.file and library.file arguments.
FASTA program options
The default scoring matrix and gap penalties used by each of the
programs have been selected for high sensitivity searches with the
various algorithms. The default program behavior can be modified by
providing command line options before the query.file and
library.file arguments. Command line options can also be used in
Command line arguments come in several classes.
(1) Commands that specify the comparison type. FASTA, FASTS, FASTM,
SSEARCH, GGSEARCH, and GLSEARCH can compare either protein or DNA
sequences, and attempt to recognize the comparison type by looking the
residue composition. -n, -p specify DNA (nucleotide) or
protein comparison, respectively. -U specifies RNA comparison.
(2) Commands that limit the set of sequences compared: -1,
(3) Commands that modify the scoring parameters: -f gap-open penaltyP, -g
gap-extend penalty, -j inter-codon frame-shift, within-codon frameshift,
-s scoring-matrix, -r
match/mismatch score, -x X:X score.
(4) Commands that modify the algorithm (mostly FASTA and [T]FASTX/Y):
-c, -w, -y, -o. The -S can be used to
ignore lower-case (low complexity) residues during the initial score
(5) Commands that modify the output: -A, -b number, -C
width, -d number, -L, -m 0-11,B, -w
line-width, -W context-width, -o offset1,ofset2
(6) Commands that affect statistical estimates: -Z, -k.
Sort by "init1" score (obsolete)
([t]fast[x,y] only) use only forward frame translations
Displays the full length (included unaligned regions) of both
sequences with fasta36, ssearch36, glsearch36, and fasts36.
- -A (fasta36 only) For DNA:DNA, force Smith-Waterman alignment for
output. Smith-Waterman is the default for FASTA protein alignment and
[t]fast[x,y], but not for DNA comparisons with FASTA. For
protein:protein, use band-alignment algorithm.
- -b #
number of best scores/descriptions to show (must be <
expectation cutoff if -E is given). By default, this option is no
longer used; all scores better than the expectation (E()) cutoff are
listed. To guarantee the display of # descriptions/scores, use -b
=#, i.e. -b =100 ensures that 100 descriptions/scores will be
displayed. To guarantee at least 1 description, but possibly many
more (limited by -E e_cut), use -b >1.
- -c "E-opt E-join"
threshold for gap joining (E-join) and band optimization (E-opt) in
FASTA and [T]FASTX/Y. FASTA36 now uses BLAST-like statistical
thresholds for joining and band optimization. The default statistical
thresholds for protein and translated comparisons are E-opt=0.2,
E-join=0.5; for DNA, E-join = 0.1 and E-opt= 0.02. The actual number
of joins and optimizations is reported after the E-join and E-opt
scoring parameters. Statistical thresholds improves search speed 2 -
3X, and provides much more accurate statistical estimates for matrices
other than BLOSUM50. The "classic" joining/optimization thresholds
that were the default in fasta35 and earlier programs are available
using -c O (upper case O), possibly followed a value > 1.0 to set
the optcut optimization threshold.
- -C #
length of name abbreviation in alignments, default = 6. Must be less
- -d #
number of best alignments to show ( must be < expectation (-E) cutoff
and <= the -b description limit).
turn on debugging mode. Enables checks on sequence alphabet that
cause problems with tfastx36, tfasty36 (only available after compile
time option). Also preserves temp files with -e expand_script.sh option.
- -e expand_script.sh
Run a script to expand the set of sequences displayed/aligned based on
the results of the initial search. When the -e expand_script.sh
option is used, after the initial scan and statistics calculation, but
before the "Best scores" are shown, expand_script.sh with a single
argument, the name of a file that contains the accession information
(the text on the fasta description line between > and the first space)
and the E()-value for the sequence. expand_script.sh then uses this
information to send a library of additional sequences to stdout. These
additional sequences are included in the list of high-scoring
sequences (if their scores are significant) and aligned. The
additional sequences do not change the statistics or database size.
- -E e_cut e_cut_r
expectation value upper limit for score and alignment display.
Defaults are 10.0 for FASTA36 and SSEARCH36 protein searches, 5.0 for
translated DNA/protein comparisons, and 2.0 for DNA/DNA
searches. FASTA version 36 now reports additional alignments between
the query and the library sequence, the second value sets the
threshold for the subsequent alignments. If not given, the threshold
is e_cut/10.0. If given and value > 1.0, e_cut_r = e_cut / value; for
value < 1.0, e_cut_r = value; If e_cut_r < 0, then the additional
alignment option is disabled.
- -f #
penalty for opening a gap.
- -F #
expectation value lower limit for score and alignment display.
-F 1e-6 prevents library sequences with E()-values lower than 1e-6
from being displayed. This allows the use to focus on more distant
- -g #
penalty for additional residues in a gap
Show short help message.
Show long help message, with all options.
show histogram (with fasta-36.3.4, the histogram is not shown by default).
(fasta DNA, [t]fastx[x,y]) compare against
only the reverse complement of the library sequence.
interactive mode; prompt for query filename, library.
- -j # #
([t]fast[x,y] only) penalty for a frameshift between two codons,
([t]fasty only) penalty for a frameshift within a codon.
(lalign36 only) show identity alignment.
specify number of shuffles for statistical parameter estimation (default=500).
- -l str
specify FASTLIBS file
report long sequence description in alignments (up to 200 characters).
- -m 0,1,2,3,4,5,6,8,9,10,11,B,BB,"F# out.file" alignment display
options. -m 0, 1, 2, 3 display different types of alignments.
-m 4 provides an alignment "map" on the query. -m 5
combines the alignment map and a -m 0 alignment. -m 6
provides an HTML output.
- -m 8 seeks to mimic BLAST -m 8 tabular output. Only query and
library sequence names, and identity, mismatch, starts/stops,
E()-values, and bit scores are displayed. -m 8C mimics BLAST
tabular format with comment lines. -m 8 formats do not show
- -m 9 does not change the alignment output, but provides
alignment coordinate and percent identity information with the best
scores report. -m 9c adds encoded alignment information to the
-m 9; -m 9C adds encoded alignment information as a CIGAR
formatted string. To accomodate frameshifts, the CIGAR format has been
supplemented with F (forward) and R (reverse). -m 9i provides
only percent identity and alignment length information with the best
scores. With current versions of the FASTA programs, independent
-m options can be combined; e.g. -m 1 -m 9c -m 6.
- -m 11 provides lav format output from lalign36. It does not
currently affect other alignment algorithms. The lav2ps and
lav2svg programs can be used to convert lav format output
to postscript/SVG alignment "dot-plots".
- -m B provides BLAST-like alignments. Alignments are labeled as
"Query" and "Sbjct", with coordinates on the same line as the
sequences, and BLAST-like symbols for matches and
mismatches. -m BB extends BLAST similarity to all the output,
providing an output that closely mimics BLAST output.
- -m "F# out.file" allows one search to write different alignment
formats to different files. The 'F' indicates separate file output;
the '#' is the output format (1-6,8,9,10,11,B,BB, multiple compatible
formats can be combined separated by commas -',').
- -M #-#
molecular weight (residue) cutoffs. -M "101-200" examines only
library sequences that are 101-200 residues long.
force query to nucleotide sequence
- -N #
break long library sequences into blocks of # residues. Useful for
bacterial genomes, which have only one sequence entry. -N 2000 works
well for well for bacterial genomes. (This option was required when
FASTA only provided one alignment between the query and library
sequence. It is not as useful, now that multiple alignments are
- -o "#,#"
offsets query, library sequence for numbering alignments
- -O file
send output to file.
force query to protein alphabet.
- -P pssm_file
(ssearch36, ggsearch36, glsearch36 only). Provide blastpgp checkpoint
file as the PSSM for searching. Two PSSM file formats are available,
which must be provided with the filename. 'pssm_file 0' uses a binary
format that is machine specific; 'pssm_file 1' uses the "blastpgp -u 1
-C pssm_file" ASN.1 binary format (preferred).
quiet option; do not prompt for input (on by default)
- -r "+n/-m"
(DNA only) values for match/mismatch for DNA comparisons. +n is
used for the maximum positive value and -m is used for the
maximum negative value. Values between max and min, are rescaled, but
residue pairs having the value -1 continue to be -1.
- -R file
save all scores to statistics file (previously -r file)
- -s name
specify substitution matrix. BLOSUM50 is used by default; PAM250,
PAM120, and BLOSUM62 can be specified by setting -s P120, P250, or
BL62. Additional scoring matrices include: BLOSUM80 (BL80), and
MDM10, MDM20, MDM40 (Jones, Taylor, and Thornton, 1992 CABIOS
8:275-282; specified as -s MD10, -s MD20, -s MD40), OPTIMA5 (-s OPT5,
Kann and Goldstein, (2002) Proteins 48:367-376), and VTML160 (-s
VT160, Mueller and Vingron (2002) J. Comp. Biol. 19:8-13). Each
scoring matrix has associated default gap penalties. The BLOSUM62
scoring matrix and -11/-1 gap penalties can be specified with -s BP62.
Alternatively, a BLASTP format scoring matrix file can be specified,
e.g. -s matrix.filename. DNA scoring matrices can also be specified
with the "-r" option.
With fasta36.3, variable scoring matrices can
be specified by preceeding the scoring matrix abbreviation with '?',
e.g. -s '?BP62'. Variable scoring matrices allow the FASTA programs to
choose an alternative scoring matrix with higher information content
(bit score/position) when short queries are used. For example, a 90
nucleotide FASTX query can produce only a 30 amino-acid alignment, so
a scoring matrix with 1.33 bits/position is required to produce a 40
bit score. The FASTA programs include BLOSUM50 (0.49 bits/pos) and
BLOSUM62 (0.58 bits/pos) but can range to MD10 (3.44
bits/position). The variable scoring matrix option searches down the
list of scoring matrices to find one with information content high
enough to produce a 40 bit alignment score.
treat lower case letters in the query or database as low complexity
regions that are equivalent to 'X' during the initial database scan,
but are treated as normal residues for the final alignment display.
Statistical estimates are based on the 'X'ed out sequence used during
the initial search. Protein databases (and query sequences) can be
generated in the appropriate format using John Wooton's "pseg"
program, available from ftp://ftp.ncbi.nih.gov/pub/seg/pseg. Once you
have compiled the "pseg" program, use the command:
pseg database.fasta -z 1 -q > database.lc_seg
- -t #
Translation table - [t]fastx36 and [t]fasty36 support the BLAST
tranlation tables. See
- -T #
(threaded, parallel only) number of threads or workers to use (on
Linux/MacOS/Unix, the default is to use as many processors as are
available; on Windows systems, 2 processors are used).
Do RNA sequence comparisons: treat 'T' as 'U', allow G:U base pairs (by
scoring "G-A" and "T-C" as score(G:G)-3). Search only one strand.
- -V "?$%*"
Allow special annotation characters in query sequence. These characters
will be displayed in the alignments on the coordinate number line.
- -w # line width for similarity score, sequence alignment, output.
- -W # context length (default is 1/2 of line width -w) for alignment,
like fasta and ssearch, that provide additional sequence context.
- -X extended options. Less used options. Other options include
-XB, -XM4G, -Xo, -Xx, and -Xy; see
- -z 1, 2, 3, 4, 5, 6
Specify the statistical calculation. Default is -z 1 for local
similarity searches, which uses regression against the length of the
library sequence. -z -1 disables statistics. -z 0 estimates
significance without normalizing for sequence length. -z 2 provides
maximum likelihood estimates for lambda and K, censoring the 250
lowest and 250 highest scores. -z 3 uses Altschul and Gish's
statistical estimates for specific protein BLOSUM scoring matrices and
gap penalties. -z 4,5: an alternate regression method. -z 6 uses a
composition based maximum likelihood estimate based on the method of
Mott (1992) Bull. Math. Biol. 54:59-75.
- -z 11,12,14,15,16
compute the regression against scores of randomly
shuffled copies of the library sequences. Twice as many comparisons
are performed, but accurate estimates can be generated from databases
of related sequences. -z 11 uses the -z 1 regression strategy, etc.
- -z 21, 22, 24, 25, 26
compute two E()-values. The standard (library-based) E()-value is
calculated in the standard way (-z 1, 2, etc), but a second E2()
value is calculated by shuffling the high-scoring sequences (those
with E()-values less than the threshold). For "average" composition
proteins, these two estimates will be similar (though the
best-shuffle estimates are always more conservative). For biased
composition proteins, the two estimates may differ by 100-fold or
more. A second -z option, e.g. -z "21 2", specifies the estimation
method for the best-shuffle E2()-values. Best-shuffle E2()-values
approximate the estimates given by PRSS (or in a pairwise SSEARCH).
- -Z db_size
Set the apparent database size used for expectation value calculations
(used for protein/protein FASTA and SSEARCH, and for [T]FASTX/Y).
Reading sequences from STDIN
The FASTA programs can accept a query sequence from
the unix "stdin" data stream. This makes it much easier to use
fasta36 and its relatives as part of a WWW page. To indicate that
stdin is to be used, use "@" as the query sequence file name. "@" can
also be used to specify a subset of the query sequence to be used,
cat query.aa | fasta36 @:50-150 s
would search the 's' database with residues 50-150 of query.aa. FASTA
cannot automatically detect the sequence type (protein vs DNA) when
"stdin" is used and assumes protein comparisons by default; the '-n'
option is required for DNA for STDIN queries.
location of library choice file (-l FASTLIBS)
- SRCH_URL1, SRCH_URL2
format strings used to define options to re-search the
the format string used to define the option to lookup the library
sequence in entrez, or some other database.
Version: $ Id: $
Revision: $Revision: 210 $
- Running the FASTA programs
- FASTA program options
- Option summary:
- Reading sequences from STDIN
- Environment variables:
This document was created by
using the manual pages.
Time: 01:09:32 GMT, September 30, 2014