
                                  needle 



Function

   Needleman-Wunsch global alignment

Description

   This program uses the Needleman-Wunsch global alignment algorithm to
   find the optimum alignment (including gaps) of two sequences when
   considering their entire length.

   What is the optimal alignment? Dynamic programming methods ensure the
   optimal global 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. Needle
   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.

  Algorithm

   The Needleman-Wunsch algorithm is a member of the class of algorithms
   that can calculate the best score and 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 Needleman and Wunsch, 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.

   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.

   In a Needleman-Wunsch global alignment, the entire length of each
   sequence is aligned. This can be thought of as an overlap between the
   two sequences (one can be completely within the otehr, or their ends
   can overlap).

   This leaves no penalty for the hanging ends of the overlap. In
   bioinformatics, it is usually reasonable to assume that the sequences
   are incomplete and there should be no penalty for failing to align the
   missing bases.

Usage

   Here is a sample session with needle


% needle tsw:hba_human tsw:hbb_human 
Needleman-Wunsch global alignment.
Gap opening penalty [10.0]: 
Gap extension penalty [0.5]: 
Output alignment [hba_human.needle]: 

   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.
   Floating point number from 1.0 to 100.0 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. Floating point number from 0.0 to 10.0 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

   needle reads any 2 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.needle

########################################
# Program: needle
# Rundate: Thu Jul 15 2004 12:00:00
# Align_format: srspair
# Report_file: hba_human.needle
########################################

#=======================================
#
# Aligned_sequences: 2
# 1: HBA_HUMAN
# 2: HBB_HUMAN
# Matrix: EBLOSUM62
# Gap_penalty: 10.0
# Extend_penalty: 0.5
#
# Length: 148
# Identity:      63/148 (42.6%)
# Similarity:    88/148 (59.5%)
# Gaps:           9/148 ( 6.1%)
# Score: 290.5
#
#
#=======================================

HBA_HUMAN          1 -VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHF-DL     48
                      .|:|.:|:.|.|.||||  :..|.|.|||.|:.:.:|.|:.:|..| ||
HBB_HUMAN          1 VHLTPEEKSAVTALWGKV--NVDEVGGEALGRLLVVYPWTQRFFESFGDL     48

HBA_HUMAN         49 S-----HGSAQVKGHGKKVADALTNAVAHVDDMPNALSALSDLHAHKLRV     93
                     |     .|:.:||.|||||..|.::.:||:|::....:.||:||..||.|
HBB_HUMAN         49 STPDAVMGNPKVKAHGKKVLGAFSDGLAHLDNLKGTFATLSELHCDKLHV     98

HBA_HUMAN         94 DPVNFKLLSHCLLVTLAAHLPAEFTPAVHASLDKFLASVSTVLTSKYR    141
                     ||.||:||.:.|:..||.|...||||.|.|:..|.:|.|:..|..||.
HBB_HUMAN         99 DPENFRLLGNVLVCVLAHHFGKEFTPPVQAAYQKVVAGVANALAHKYH    146


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

   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

   needle is a true implementation of the Needleman-Wunsch algorithm and
   so produces a full path matrix. It therefore cannot be used with
   genome sized sequences unless you've a lot of memory and a lot of
   time.

References

    1. Needleman, S. B. and Wunsch, C. D. (1970) J. Mol. Biol. 48,
       443-453.
    2. Kruskal, J. B. (1983) An overview of squence comparison In D.
       Sankoff and J. B. Kruskal, (ed.), Time warps, string edits and
       macromolecules: the theory and practice of sequence comparison,
       pp. 1-44 Addison Wesley.

Warnings

   needle is for aligning two sequences over their entire length. This
   works best with closely related sequences. If you use needle to align
   very distantly-related sequences, it will produce a result but much of
   the alignment may have little or no biological significance.

   A true Needleman Wunsch implementation like needle 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 stretcher instead.

Diagnostic Error Messages

Uncaught exception
 Assertion failed
 raised at ajmem.c:xxx

   Probably means you have run out of memory. Try using stretcher if this
   happens.

Exit status

   0 upon successful completion.

Known bugs

   None.

See also

   Program name                      Description
   est2genome   Align EST and genomic DNA sequences
   stretcher    Finds the best global alignment between two sequences

   When you want an alignment that covers the whole length of both
   sequences, use needle. 

   When you are trying to find the best region of similarity between two
   sequences, use water.

   stretcher is a more suitable program to use to find global alignments
   of very long sequences.

Author(s)

   Alan Bleasby (ableasby © rfcgr.mrc.ac.uk)
   MRC Rosalind Franklin Centre for Genomics Research Wellcome Trust
   Genome Campus, Hinxton, Cambridge, CB10 1SB, UK

History

   Completed 8th July 1999.

   Modified 26th July 1999 - scoring tweaked.

   Modified 22 Oct 2000 - %ID and %Similarity scores added.

Target users

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

Comments

   None
