
                                   water 



Function

   Smith-Waterman local alignment

Description

   water uses the Smith-Waterman algorithm (modified for speed
   enhancments) to calculate the local alignment.

   A local alignment searches for regions of local similarity between two
   sequences and need not include the entire length of the sequences.
   Local alignment methods are very useful for scanning databases or
   other circumsatnces when you wish to find matches between small
   regions of sequences, for example between protein domains.

  Algorithm

   The Smith-Waterman algorithm is a member of the class of algorithms
   that can calculate the best score and local alignment in the order of
   mn steps, (where 'n' and 'm' are the lengths of the two sequences).
   These dynamic programming algorithms were first developed for protein
   sequence comparison by Smith and Waterman, though similar methods were
   independently devised during the late 1960's and early 1970's for use
   in the fields of speech processing and computer science.

   Dynamic programming methods ensure the optimal local alignment by
   exploring all possible alignments and choosing the best. It does this
   by reading in a scoring matrix that contains values for every possible
   residue or nucleotide match. water finds an alignment with the maximum
   possible score where the score of an alignment is equal to the sum of
   the matches taken from the scoring matrix.

   An important problem is the treatment of gaps, i.e., spaces inserted
   to optimise the alignment score. A penalty is subtracted from the
   score for each gap opened (the 'gap open' penalty) and a penalty is
   subtracted from the score for the total number of gap spaces
   multiplied by a cost (the 'gap extension' penalty).

   Typically, the cost of extending a gap is set to be 5-10 times lower
   than the cost for opening a gap.

   There are two ways to compute a penalty for a gap of n positions :

gap opening penalty + (n - 1) * gap extension penalty
gap penalty + n * gap length penalty

   The first way is used by EMBOSS and WU-BLAST
   The second way is used by NCBI-BLAST, GCG, Staden and CLUSTAL. Fasta
   used it for a long time the first way, but Prof. Pearson decided
   recently to shift to the second.

   The two methods are basically equivalent.

   The Smith-Waterman algorithm contains no negative scores in the path
   matrix it creates. The algorithm starts the alignment at the highest
   path matrix score and works backwards until a cell contains zero.

   See the Reference Smith et al. for details.

Usage

   Here is a sample session with water


% water tsw:hba_human tsw:hbb_human 
Smith-Waterman local alignment.
Gap opening penalty [10.0]: 
Gap extension penalty [0.5]: 
Output alignment [hba_human.water]: 

   Go to the input files for this example
   Go to the output files for this example

Command line arguments

   Standard (Mandatory) qualifiers:
  [-asequence]         sequence   Sequence USA
  [-bsequence]         seqall     Sequence database USA
   -gapopen            float      The gap open penalty is the score taken away
                                  when a gap is created. The best value
                                  depends on the choice of comparison matrix.
                                  The default value assumes you are using the
                                  EBLOSUM62 matrix for protein sequences, and
                                  the EDNAFULL matrix for nucleotide
                                  sequences.
   -gapextend          float      The gap extension penalty is added to the
                                  standard gap penalty for each base or
                                  residue in the gap. This is how long gaps
                                  are penalized. Usually you will expect a few
                                  long gaps rather than many short gaps, so
                                  the gap extension penalty should be lower
                                  than the gap penalty. An exception is where
                                  one or both sequences are single reads with
                                  possible sequencing errors in which case you
                                  would expect many single base gaps. You can
                                  get this result by setting the gap open
                                  penalty to zero (or very low) and using the
                                  gap extension penalty to control gap
                                  scoring.
  [-outfile]           align      Output alignment file name

   Additional (Optional) qualifiers:
   -datafile           matrixf    This is the scoring matrix file used when
                                  comparing sequences. By default it is the
                                  file 'EBLOSUM62' (for proteins) or the file
                                  'EDNAFULL' (for nucleic sequences). These
                                  files are found in the 'data' directory of
                                  the EMBOSS installation.

   Advanced (Unprompted) qualifiers:
   -[no]brief          boolean    Brief identity and similarity

   Associated qualifiers:

   "-asequence" associated qualifiers
   -sbegin1             integer    Start of the sequence to be used
   -send1               integer    End of the sequence to be used
   -sreverse1           boolean    Reverse (if DNA)
   -sask1               boolean    Ask for begin/end/reverse
   -snucleotide1        boolean    Sequence is nucleotide
   -sprotein1           boolean    Sequence is protein
   -slower1             boolean    Make lower case
   -supper1             boolean    Make upper case
   -sformat1            string     Input sequence format
   -sdbname1            string     Database name
   -sid1                string     Entryname
   -ufo1                string     UFO features
   -fformat1            string     Features format
   -fopenfile1          string     Features file name

   "-bsequence" associated qualifiers
   -sbegin2             integer    Start of each sequence to be used
   -send2               integer    End of each sequence to be used
   -sreverse2           boolean    Reverse (if DNA)
   -sask2               boolean    Ask for begin/end/reverse
   -snucleotide2        boolean    Sequence is nucleotide
   -sprotein2           boolean    Sequence is protein
   -slower2             boolean    Make lower case
   -supper2             boolean    Make upper case
   -sformat2            string     Input sequence format
   -sdbname2            string     Database name
   -sid2                string     Entryname
   -ufo2                string     UFO features
   -fformat2            string     Features format
   -fopenfile2          string     Features file name

   "-outfile" associated qualifiers
   -aformat3            string     Alignment format
   -aextension3         string     File name extension
   -adirectory3         string     Output directory
   -aname3              string     Base file name
   -awidth3             integer    Alignment width
   -aaccshow3           boolean    Show accession number in the header
   -adesshow3           boolean    Show description in the header
   -ausashow3           boolean    Show the full USA in the alignment
   -aglobal3            boolean    Show the full sequence in alignment

   General qualifiers:
   -auto                boolean    Turn off prompts
   -stdout              boolean    Write standard output
   -filter              boolean    Read standard input, write standard output
   -options             boolean    Prompt for standard and additional values
   -debug               boolean    Write debug output to program.dbg
   -verbose             boolean    Report some/full command line options
   -help                boolean    Report command line options. More
                                  information on associated and general
                                  qualifiers can be found with -help -verbose
   -warning             boolean    Report warnings
   -error               boolean    Report errors
   -fatal               boolean    Report fatal errors
   -die                 boolean    Report deaths


   Standard (Mandatory) qualifiers Allowed values Default
   [-asequence]
   (Parameter 1) Sequence USA Readable sequence Required
   [-bsequence]
   (Parameter 2) Sequence database USA Readable sequence(s) Required
   -gapopen The gap open penalty is the score taken away when a gap is
   created. The best value depends on the choice of comparison matrix.
   The default value assumes you are using the EBLOSUM62 matrix for
   protein sequences, and the EDNAFULL matrix for nucleotide sequences.
   Number from 0.000 to 100.000 10.0 for any sequence
   -gapextend The gap extension penalty is added to the standard gap
   penalty for each base or residue in the gap. This is how long gaps are
   penalized. Usually you will expect a few long gaps rather than many
   short gaps, so the gap extension penalty should be lower than the gap
   penalty. An exception is where one or both sequences are single reads
   with possible sequencing errors in which case you would expect many
   single base gaps. You can get this result by setting the gap open
   penalty to zero (or very low) and using the gap extension penalty to
   control gap scoring. Number from 0.000 to 10.000 0.5 for any sequence
   [-outfile]
   (Parameter 3) Output alignment file name Alignment output file
   Additional (Optional) qualifiers Allowed values Default
   -datafile This is the scoring matrix file used when comparing
   sequences. By default it is the file 'EBLOSUM62' (for proteins) or the
   file 'EDNAFULL' (for nucleic sequences). These files are found in the
   'data' directory of the EMBOSS installation. Comparison matrix file in
   EMBOSS data path EBLOSUM62 for protein
   EDNAFULL for DNA
   Advanced (Unprompted) qualifiers Allowed values Default
   -[no]brief Brief identity and similarity Boolean value Yes/No Yes

Input file format

   water reads any two sequence USAs of the same type (DNA or protein).

  Input files for usage example

   'tsw:hba_human' is a sequence entry in the example protein database
   'tsw'

  Database entry: tsw:hba_human

ID   HBA_HUMAN      STANDARD;      PRT;   141 AA.
AC   P01922;
DT   21-JUL-1986 (Rel. 01, Created)
DT   21-JUL-1986 (Rel. 01, Last sequence update)
DT   15-JUL-1999 (Rel. 38, Last annotation update)
DE   HEMOGLOBIN ALPHA CHAIN.
GN   HBA1 AND HBA2.
OS   Homo sapiens (Human), Pan troglodytes (Chimpanzee), and
OS   Pan paniscus (Pygmy chimpanzee) (Bonobo).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Mammalia;
OC   Eutheria; Primates; Catarrhini; Hominidae; Homo.
RN   [1]
RP   SEQUENCE FROM N.A. (ALPHA-1).
RX   MEDLINE; 81088339.
RA   MICHELSON A.M., ORKIN S.H.;
RT   "The 3' untranslated regions of the duplicated human alpha-globin
RT   genes are unexpectedly divergent.";
RL   Cell 22:371-377(1980).
RN   [2]
RP   SEQUENCE FROM N.A. (ALPHA-2).
RX   MEDLINE; 81175088.
RA   LIEBHABER S.A., GOOSSENS M.J., KAN Y.W.;
RT   "Cloning and complete nucleotide sequence of human 5'-alpha-globin
RT   gene.";
RL   Proc. Natl. Acad. Sci. U.S.A. 77:7054-7058(1980).
RN   [3]
RP   SEQUENCE FROM N.A. (ALPHA-2).
RX   MEDLINE; 80137531.
RA   WILSON J.T., WILSON L.B., REDDY V.B., CAVALLESCO C., GHOSH P.K.,
RA   DERIEL J.K., FORGET B.G., WEISSMAN S.M.;
RT   "Nucleotide sequence of the coding portion of human alpha globin
RT   messenger RNA.";
RL   J. Biol. Chem. 255:2807-2815(1980).
RN   [4]
RP   SEQUENCE FROM N.A. (ALPHA-1 AND ALPHA-2).
RA   FLINT J., HIGGS D.R.;
RL   Submitted (JAN-1997) to the EMBL/GenBank/DDBJ databases.
RN   [5]
RP   SEQUENCE.
RA   BRAUNITZER G., GEHRING-MULLER R., HILSCHMANN N., HILSE K., HOBOM G.,
RA   RUDLOFF V., WITTMANN-LIEBOLD B.;
RT   "The constitution of normal adult human haemoglobin.";
RL   Hoppe-Seyler's Z. Physiol. Chem. 325:283-286(1961).
RN   [6]
RP   SEQUENCE.
RA   HILL R.J., KONIGSBERG W.;
RT   "The structure of human hemoglobin: IV. The chymotryptic digestion of
RT   the alpha chain of human hemoglobin.";
RL   J. Biol. Chem. 237:3151-3156(1962).
RN   [7]


  [Part of this file has been deleted for brevity]

FT                                /FTId=VAR_002841.
FT   VARIANT     130    130       A -> D (IN YUDA; O2 AFFINITY DOWN).
FT                                /FTId=VAR_002842.
FT   VARIANT     131    131       S -> P (IN QUESTEMBERT; HIGHLY UNSTABLE;
FT                                CAUSES ALPHA-THALASSEMIA).
FT                                /FTId=VAR_002843.
FT   VARIANT     133    133       S -> R (IN VAL DE MARNE; O2 AFFINITY UP).
FT                                /FTId=VAR_002844.
FT   VARIANT     135    135       V -> E (IN PAVIE).
FT                                /FTId=VAR_002845.
FT   VARIANT     136    136       L -> M (IN CHICAGO).
FT                                /FTId=VAR_002846.
FT   VARIANT     136    136       L -> P (IN BIBBA; UNSTABLE;
FT                                CAUSES ALPHA-THALASSEMIA).
FT                                /FTId=VAR_002847.
FT   VARIANT     138    138       S -> P (IN ATTLEBORO; O2 AFFINITY UP).
FT                                /FTId=VAR_002848.
FT   VARIANT     139    139       K -> E (IN HANAKAMI; O2 AFFINITY UP).
FT                                /FTId=VAR_002849.
FT   VARIANT     139    139       K -> T (IN TOKONAME; O2 AFFINITY UP).
FT                                /FTId=VAR_002850.
FT   VARIANT     140    140       Y -> H (IN ROUEN; O2 AFFINITY UP).
FT                                /FTId=VAR_002851.
FT   VARIANT     141    141       R -> C (IN NUNOBIKI; O2 AFFINITY UP).
FT                                /FTId=VAR_002852.
FT   VARIANT     141    141       R -> L (IN LEGNANO; O2 AFFINITY UP).
FT                                /FTId=VAR_002853.
FT   VARIANT     141    141       R -> H (IN SURESNES; O2 AFFINITY UP).
FT                                /FTId=VAR_002854.
FT   VARIANT     141    141       R -> P (IN SINGAPORE).
FT                                /FTId=VAR_002855.
FT   HELIX         4     35
FT   HELIX        37     42
FT   TURN         44     45
FT   TURN         50     51
FT   HELIX        53     71
FT   TURN         72     74
FT   HELIX        76     79
FT   TURN         80     80
FT   HELIX        81     89
FT   TURN         90     91
FT   TURN         95     95
FT   HELIX        96    112
FT   TURN        114    116
FT   HELIX       119    136
FT   TURN        137    139
SQ   SEQUENCE   141 AA;  15126 MW;  5EC7DB1E CRC32;
     VLSPADKTNV KAAWGKVGAH AGEYGAEALE RMFLSFPTTK TYFPHFDLSH GSAQVKGHGK
     KVADALTNAV AHVDDMPNAL SALSDLHAHK LRVDPVNFKL LSHCLLVTLA AHLPAEFTPA
     VHASLDKFLA SVSTVLTSKY R
//

  Database entry: tsw:hbb_human

ID   HBB_HUMAN      STANDARD;      PRT;   146 AA.
AC   P02023;
DT   21-JUL-1986 (Rel. 01, Created)
DT   21-JUL-1986 (Rel. 01, Last sequence update)
DT   15-JUL-1999 (Rel. 38, Last annotation update)
DE   HEMOGLOBIN BETA CHAIN.
GN   HBB.
OS   Homo sapiens (Human), Pan troglodytes (Chimpanzee), and
OS   Pan paniscus (Pygmy chimpanzee) (Bonobo).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Mammalia;
OC   Eutheria; Primates; Catarrhini; Hominidae; Homo.
RN   [1]
RP   SEQUENCE.
RC   SPECIES=HUMAN;
RA   BRAUNITZER G., GEHRING-MULLER R., HILSCHMANN N., HILSE K., HOBOM G.,
RA   RUDLOFF V., WITTMANN-LIEBOLD B.;
RT   "The constitution of normal adult human haemoglobin.";
RL   Hoppe-Seyler's Z. Physiol. Chem. 325:283-286(1961).
RN   [2]
RP   SEQUENCE FROM N.A.
RC   SPECIES=HUMAN;
RX   MEDLINE; 81064667.
RA   LAWN R.M., EFSTRATIADIS A., O'CONNELL C., MANIATIS T.;
RT   "The nucleotide sequence of the human beta-globin gene.";
RL   Cell 21:647-651(1980).
RN   [3]
RP   SEQUENCE OF 121-146 FROM N.A.
RC   SPECIES=HUMAN;
RX   MEDLINE; 85205333.
RA   LANG K.M., SPRITZ R.A.;
RT   "Cloning specific complete polyadenylylated 3'-terminal cDNA
RT   segments.";
RL   Gene 33:191-196(1985).
RN   [4]
RP   X-RAY CRYSTALLOGRAPHY (2.5 ANGSTROMS) OF DEOXYHEMOGLOBIN.
RC   SPECIES=HUMAN;
RX   MEDLINE; 76027820.
RA   FERMI G.;
RT   "Three-dimensional fourier synthesis of human deoxyhaemoglobin at
RT   2.5-A resolution: refinement of the atomic model.";
RL   J. Mol. Biol. 97:237-256(1975).
RN   [5]
RP   SEQUENCE.
RC   SPECIES=P.TROGLODYTES;
RX   MEDLINE; 66071496.
RA   RIFKIN D.B., KONIGSBERG W.;
RT   "The characterization of the tryptic peptides from the hemoglobin of
RT   the chimpanzee (Pan troglodytes).";
RL   Biochim. Biophys. Acta 104:457-461(1965).
RN   [6]


  [Part of this file has been deleted for brevity]

FT   VARIANT     140    140       A -> T (IN ST JACQUES: O2 AFFINITY UP).
FT                                /FTId=VAR_003081.
FT   VARIANT     140    140       A -> V (IN PUTTELANGE; POLYCYTHEMIA;
FT                                O2 AFFINITY UP).
FT                                /FTId=VAR_003082.
FT   VARIANT     141    141       L -> R (IN OLMSTED; UNSTABLE).
FT                                /FTId=VAR_003083.
FT   VARIANT     142    142       A -> D (IN OHIO; O2 AFFINITY UP).
FT                                /FTId=VAR_003084.
FT   VARIANT     143    143       H -> D (IN RANCHO MIRAGE).
FT                                /FTId=VAR_003085.
FT   VARIANT     143    143       H -> Q (IN LITTLE ROCK; O2 AFFINITY UP).
FT                                /FTId=VAR_003086.
FT   VARIANT     143    143       H -> P (IN SYRACUSE; O2 AFFINITY UP).
FT                                /FTId=VAR_003087.
FT   VARIANT     143    143       H -> R (IN ABRUZZO; O2 AFFINITY UP).
FT                                /FTId=VAR_003088.
FT   VARIANT     144    144       K -> E (IN MITO; O2 AFFINITY UP).
FT                                /FTId=VAR_003089.
FT   VARIANT     145    145       Y -> C (IN RAINIER; O2 AFFINITY UP).
FT                                /FTId=VAR_003090.
FT   VARIANT     145    145       Y -> H (IN BETHESDA; O2 AFFINITY UP).
FT                                /FTId=VAR_003091.
FT   VARIANT     146    146       H -> D (IN HIROSHIMA; O2 AFFINITY UP).
FT                                /FTId=VAR_003092.
FT   VARIANT     146    146       H -> L (IN COWTOWN; O2 AFFINITY UP).
FT                                /FTId=VAR_003093.
FT   VARIANT     146    146       H -> P (IN YORK; O2 AFFINITY UP).
FT                                /FTId=VAR_003094.
FT   VARIANT     146    146       H -> Q (IN KODAIRA; O2 AFFINITY UP).
FT                                /FTId=VAR_003095.
FT   HELIX         5     15
FT   TURN         16     17
FT   HELIX        20     34
FT   HELIX        36     41
FT   HELIX        43     45
FT   HELIX        51     55
FT   TURN         56     56
FT   HELIX        58     75
FT   TURN         76     77
FT   HELIX        78     94
FT   TURN         95     96
FT   TURN        100    100
FT   HELIX       101    121
FT   HELIX       124    142
FT   TURN        143    144
SQ   SEQUENCE   146 AA;  15867 MW;  EC9744C9 CRC32;
     VHLTPEEKSA VTALWGKVNV DEVGGEALGR LLVVYPWTQR FFESFGDLST PDAVMGNPKV
     KAHGKKVLGA FSDGLAHLDN LKGTFATLSE LHCDKLHVDP ENFRLLGNVL VCVLAHHFGK
     EFTPPVQAAY QKVVAGVANA LAHKYH
//

Output file format

   The output is a standard EMBOSS alignment file.

   The results can be output in one of several styles by using the
   command-line qualifier -aformat xxx, where 'xxx' is replaced by the
   name of the required format. Some of the alignment formats can cope
   with an unlimited number of sequences, while others are only for pairs
   of sequences.

   The available multiple alignment format names are: unknown, multiple,
   simple, fasta, msf, trace, srs

   The available pairwise alignment format names are: pair, markx0,
   markx1, markx2, markx3, markx10, srspair, score

   See: http://emboss.sf.net/docs/themes/AlignFormats.html for further
   information on alignment formats.

  Output files for usage example

  File: hba_human.water

########################################
# Program: water
# Rundate: Fri Jul 15 2005 12:00:00
# Align_format: srspair
# Report_file: hba_human.water
########################################

#=======================================
#
# Aligned_sequences: 2
# 1: HBA_HUMAN
# 2: HBB_HUMAN
# Matrix: EBLOSUM62
# Gap_penalty: 10.0
# Extend_penalty: 0.5
#
# Length: 145
# Identity:      63/145 (43.4%)
# Similarity:    88/145 (60.7%)
# Gaps:           8/145 ( 5.5%)
# Score: 293.5
#
#
#=======================================

HBA_HUMAN          2 LSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHF-DLS-     49
                     |:|.:|:.|.|.||||  :..|.|.|||.|:.:.:|.|:.:|..| |||
HBB_HUMAN          3 LTPEEKSAVTALWGKV--NVDEVGGEALGRLLVVYPWTQRFFESFGDLST     50

HBA_HUMAN         50 ----HGSAQVKGHGKKVADALTNAVAHVDDMPNALSALSDLHAHKLRVDP     95
                         .|:.:||.|||||..|.::.:||:|::....:.||:||..||.|||
HBB_HUMAN         51 PDAVMGNPKVKAHGKKVLGAFSDGLAHLDNLKGTFATLSELHCDKLHVDP    100

HBA_HUMAN         96 VNFKLLSHCLLVTLAAHLPAEFTPAVHASLDKFLASVSTVLTSKY    140
                     .||:||.:.|:..||.|...||||.|.|:..|.:|.|:..|..||
HBB_HUMAN        101 ENFRLLGNVLVCVLAHHFGKEFTPPVQAAYQKVVAGVANALAHKY    145


#---------------------------------------
#---------------------------------------

   The Identity: is the percentage of identical matches between the two
   sequences over the reported aligned region (including any gaps in the
   length).

   The Similarity: is the percentage of matches between the two sequences
   over the reported aligned region (including any gaps in the length).

Data files

   For protein sequences EBLOSUM62 is used for the substitution matrix.
   For nucleotide sequence, EDNAFULL is used. Others can be specified.

   EMBOSS data files are distributed with the application and stored in
   the standard EMBOSS data directory, which is defined by the EMBOSS
   environment variable EMBOSS_DATA.

   To see the available EMBOSS data files, run:

% embossdata -showall

   To fetch one of the data files (for example 'Exxx.dat') into your
   current directory for you to inspect or modify, run:

% embossdata -fetch -file Exxx.dat

   Users can provide their own data files in their own directories.
   Project specific files can be put in the current directory, or for
   tidier directory listings in a subdirectory called ".embossdata".
   Files for all EMBOSS runs can be put in the user's home directory, or
   again in a subdirectory called ".embossdata".

   The directories are searched in the following order:
     * . (your current directory)
     * .embossdata (under your current directory)
     * ~/ (your home directory)
     * ~/.embossdata

Notes

   water is a true implementation of the Smith-Waterman algorithm and so
   produces a full path matrix. It therefore cannot be used with genome
   sized sequences unless you have a lot of memory and a lot of time.

References

    1. Smith TF, Waterman MS (1981) J. Mol. Biol 147(1);195-7

Warnings

   Local alignment methods only report the best matching areas between
   two sequences - there may be a large number of alternative local
   alignments that do not score as highly. If two proteins share more
   than one common region, for example one has a single copy of a
   particular domain while the other has two copies, it may be possible
   to "miss" the second and subsequent alignments. You will be able to
   see this situation if you have done a dotplot and your local alignment
   does not show all the features you expected to see.

   water is for aligning the best matching subsequences of two sequences.
   It does not necessarily align whole sequences against each other; you
   should use needle if you wish to align closely related sequences along
   their whole lengths.

   A true Smith Waterman implementation like water needs memory
   proportional to the product of the sequence lengths. For two sequences
   of length 10,000,000 and 1,000 it therefore needs memory proportional
   to 10,000,000,000 characters. Two arrays of this size are produced,
   one of ints and one of floats so multiply that figure by 8 to get the
   memory usage in bytes. That doesn't include other overheads. Therefore
   only use water and needle for accurate alignment of reasonably short
   sequences.

   If you run out of memory, try using supermatcher or matcher.

Diagnostic Error Messages

Uncaught exception
 Assertion failed
 raised at ajmem.c:xxx

   Probably means you have run out of memory. Try using supermatcher or
   matcher if this happens.

Exit status

   0 if successful.

Known bugs

   None.

See also

   Program name                         Description
   matcher      Finds the best local alignments between two sequences
   seqmatchall  All-against-all comparison of a set of sequences
   supermatcher Match large sequences against one or more other sequences
   wordmatch    Finds all exact matches of a given size between 2 sequences

   matcher is a local alignment program that gives as good an alignment
   as

   water
   but it uses far less memory. However,

   water
   runs twice as fast as matcher.

   supermatcher is designed for local alignments of very large sequences.
   It gives good results as long as there is not significant amounts of
   insertion or deletion in the alignment.

   supermatcher Finds a match of a large sequence against one or more
   sequences matcher Finds the best local alignments between two
   sequences

Author(s)

   Alan Bleasby (ajb  ebi.ac.uk)
   European Bioinformatics Institute, Wellcome Trust Genome Campus,
   Hinxton, Cambridge CB10 1SD, UK

History

   Completed 7th July 1999.

   Modified 27th July 1999 - tweaking scoring.

   Modified 22 Oct 2000 - added ID and Similarity scores.

Target users

   This program is intended to be used by everyone and everything, from
   naive users to embedded scripts.

Comments

   None
