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<HTML>

<HEAD>
  <TITLE>
  EMBOSS: emma
  </TITLE>
</HEAD>
<BODY BGCOLOR="#FFFFFF" text="#000000">

<table align=center border=0 cellspacing=0 cellpadding=0>
<tr><td valign=top>
<A HREF="/" ONMOUSEOVER="self.status='Go to the EMBOSS home page';return true"><img border=0 src="/images/emboss_icon.jpg" alt="" width=150 height=48></a>
</td>
<td align=left valign=middle>
<b><font size="+6">
emma
</font></b>
</td></tr>
</table>
<br>&nbsp;
<p>

<H2>
Wiki
</H2>

The master copies of EMBOSS documentation are available
at <a href="http://emboss.open-bio.org/wiki/Appdocs">
http://emboss.open-bio.org/wiki/Appdocs</a>
on the EMBOSS Wiki.

<p>
Please help by correcting and extending the Wiki pages.

<H2>
    Function
</H2>
Multiple sequence alignment (ClustalW wrapper)
<H2>
    Description
</H2>

EMMA calculates the multiple alignment of nucleic acid or protein
sequences according to the method of Thompson, J.D., Higgins, D.G.
and Gibson, T.J. (1994).

<p>

This is an interface to the ClustalW distribution.




<H2>
    Usage
</H2>
Here is a sample session with <b>emma</b>
<p>

<p>
<table width="90%"><tr><td bgcolor="#CCFFFF"><pre>

% <b>emma </b>
Multiple sequence alignment (ClustalW wrapper)
Input (gapped) sequence(s): <b>globins.fasta</b>
(aligned) output sequence set [hbb_human.aln]: <b></b>
Dendrogram (tree file) from clustalw output file [hbb_human.dnd]: <b></b>




 CLUSTAL 2.1 Multiple Sequence Alignments


Sequence type explicitly set to Protein
Sequence format is Pearson
Sequence 1: HBB_HUMAN    146 aa
Sequence 2: HBB_HORSE    146 aa
Sequence 3: HBA_HUMAN    141 aa
Sequence 4: HBA_HORSE    141 aa
Sequence 5: MYG_PHYCA    153 aa
Sequence 6: GLB5_PETMA   149 aa
Sequence 7: LGB2_LUPLU   153 aa
Start of Pairwise alignments
Aligning...

Sequences (1:2) Aligned. Score:  83
Sequences (1:3) Aligned. Score:  43
Sequences (1:4) Aligned. Score:  42
Sequences (1:5) Aligned. Score:  24
Sequences (1:6) Aligned. Score:  21
Sequences (1:7) Aligned. Score:  14
Sequences (2:3) Aligned. Score:  41
Sequences (2:4) Aligned. Score:  43
Sequences (2:5) Aligned. Score:  24
Sequences (2:6) Aligned. Score:  19
Sequences (2:7) Aligned. Score:  15
Sequences (3:4) Aligned. Score:  87
Sequences (3:5) Aligned. Score:  26
Sequences (3:6) Aligned. Score:  29
Sequences (3:7) Aligned. Score:  16
Sequences (4:5) Aligned. Score:  26
Sequences (4:6) Aligned. Score:  27
Sequences (4:7) Aligned. Score:  12
Sequences (5:6) Aligned. Score:  21
Sequences (5:7) Aligned. Score:  7
Sequences (6:7) Aligned. Score:  11
Guide tree file created:   [12345678A]

There are 6 groups
Start of Multiple Alignment

Aligning...
Group 1: Sequences:   2      Score:2194
Group 2: Sequences:   2      Score:2165
Group 3: Sequences:   4      Score:960
Group 4:                     Delayed
Group 5:                     Delayed
Group 6:                     Delayed
Alignment Score 4164

GCG-Alignment file created      [12345678A]


</pre></td></tr></table><p>
<p>
<a href="#input.1">Go to the input files for this example</a><br><a href="#output.1">Go to the output files for this example</a><p><p>


<H2>
    Command line arguments
</H2>
<table CELLSPACING=0 CELLPADDING=3 BGCOLOR="#f5f5ff" ><tr><td>
<pre>
Multiple sequence alignment (ClustalW wrapper)
Version: EMBOSS:6.6.0.0

   Standard (Mandatory) qualifiers:
  [-sequence]          seqall     (Gapped) sequence(s) filename and optional
                                  format, or reference (input USA)
  [-outseq]            seqoutset  [<sequence>.<format>] Sequence set filename
                                  and optional format (output USA)
  [-dendoutfile]       outfile    [*.emma] Dendrogram (tree file) from
                                  clustalw output file

   Additional (Optional) qualifiers (* if not always prompted):
   -onlydend           toggle     [N] Only produce dendrogram file
*  -dendreuse          toggle     [N] Do alignment using an old dendrogram
*  -dendfile           infile     Dendrogram (tree file) from clustalw file
                                  (optional)
   -[no]slowalign      toggle     [Y] A distance is calculated between every
                                  pair of sequences and these are used to
                                  construct the dendrogram which guides the
                                  final multiple alignment. The scores are
                                  calculated from separate pairwise
                                  alignments. These can be calculated using 2
                                  methods: dynamic programming (slow but
                                  accurate) or by the method of Wilbur and
                                  Lipman (extremely fast but approximate).
                                  The slow-accurate method is fine for short
                                  sequences but will be VERY SLOW for many
                                  (e.g. >100) long (e.g. >1000 residue)
                                  sequences.
*  -pwmatrix           menu       [b] The scoring table which describes the
                                  similarity of each amino acid to each other.
                                  There are three 'in-built' series of weight
                                  matrices offered. Each consists of several
                                  matrices which work differently at different
                                  evolutionary distances. To see the exact
                                  details, read the documentation. Crudely, we
                                  store several matrices in memory, spanning
                                  the full range of amino acid distance (from
                                  almost identical sequences to highly
                                  divergent ones). For very similar sequences,
                                  it is best to use a strict weight matrix
                                  which only gives a high score to identities
                                  and the most favoured conservative
                                  substitutions. For more divergent sequences,
                                  it is appropriate to use 'softer' matrices
                                  which give a high score to many other
                                  frequent substitutions.
                                  1) BLOSUM (Henikoff). These matrices appear
                                  to be the best available for carrying out
                                  data base similarity (homology searches).
                                  The matrices used are: Blosum80, 62, 45 and
                                  30.
                                  2) PAM (Dayhoff). These have been extremely
                                  widely used since the late '70s. We use the
                                  PAM 120, 160, 250 and 350 matrices.
                                  3) GONNET . These matrices were derived
                                  using almost the same procedure as the
                                  Dayhoff one (above) but are much more up to
                                  date and are based on a far larger data set.
                                  They appear to be more sensitive than the
                                  Dayhoff series. We use the GONNET 40, 80,
                                  120, 160, 250 and 350 matrices.
                                  We also supply an identity matrix which
                                  gives a score of 1.0 to two identical amino
                                  acids and a score of zero otherwise. This
                                  matrix is not very useful. (Values: b
                                  (blosum); p (pam); g (gonnet); i (id); o
                                  (own))
*  -pwdnamatrix        menu       [i] The scoring table which describes the
                                  scores assigned to matches and mismatches
                                  (including IUB ambiguity codes). (Values: i
                                  (iub); c (clustalw); o (own))
*  -pairwisedatafile   infile     Comparison matrix file (optional)
*  -matrix             menu       [b] This gives a menu where you are offered
                                  a choice of weight matrices. The default for
                                  proteins is the PAM series derived by
                                  Gonnet and colleagues. Note, a series is
                                  used! The actual matrix that is used depends
                                  on how similar the sequences to be aligned
                                  at this alignment step are. Different
                                  matrices work differently at each
                                  evolutionary distance.
                                  There are three 'in-built' series of weight
                                  matrices offered. Each consists of several
                                  matrices which work differently at different
                                  evolutionary distances. To see the exact
                                  details, read the documentation. Crudely, we
                                  store several matrices in memory, spanning
                                  the full range of amino acid distance (from
                                  almost identical sequences to highly
                                  divergent ones). For very similar sequences,
                                  it is best to use a strict weight matrix
                                  which only gives a high score to identities
                                  and the most favoured conservative
                                  substitutions. For more divergent sequences,
                                  it is appropriate to use 'softer' matrices
                                  which give a high score to many other
                                  frequent substitutions.
                                  1) BLOSUM (Henikoff). These matrices appear
                                  to be the best available for carrying out
                                  data base similarity (homology searches).
                                  The matrices used are: Blosum80, 62, 45 and
                                  30.
                                  2) PAM (Dayhoff). These have been extremely
                                  widely used since the late '70s. We use the
                                  PAM 120, 160, 250 and 350 matrices.
                                  3) GONNET . These matrices were derived
                                  using almost the same procedure as the
                                  Dayhoff one (above) but are much more up to
                                  date and are based on a far larger data set.
                                  They appear to be more sensitive than the
                                  Dayhoff series. We use the GONNET 40, 80,
                                  120, 160, 250 and 350 matrices.
                                  We also supply an identity matrix which
                                  gives a score of 1.0 to two identical amino
                                  acids and a score of zero otherwise. This
                                  matrix is not very useful. Alternatively,
                                  you can read in your own (just one matrix,
                                  not a series). (Values: b (blosum); p (pam);
                                  g (gonnet); i (id); o (own))
*  -dnamatrix          menu       [i] This gives a menu where a single matrix
                                  (not a series) can be selected. (Values: i
                                  (iub); c (clustalw); o (own))
*  -mamatrixfile       infile     Comparison matrix file (optional)
*  -pwgapopen          float      [10.0] The penalty for opening a gap in the
                                  pairwise alignments. (Number 0.000 or more)
*  -pwgapextend        float      [0.1] The penalty for extending a gap by 1
                                  residue in the pairwise alignments. (Number
                                  0.000 or more)
*  -ktup               integer    [1 for protein, 2 for nucleic] This is the
                                  size of exactly matching fragment that is
                                  used. INCREASE for speed (max= 2 for
                                  proteins; 4 for DNA), DECREASE for
                                  sensitivity. For longer sequences (e.g.
                                  >1000 residues) you may need to increase the
                                  default. (integer from 0 to 4)
*  -gapw               integer    [3 for protein, 5 for nucleic] This is a
                                  penalty for each gap in the fast alignments.
                                  It has little affect on the speed or
                                  sensitivity except for extreme values.
                                  (Positive integer)
*  -topdiags           integer    [5 for protein, 4 for nucleic] The number of
                                  k-tuple matches on each diagonal (in an
                                  imaginary dot-matrix plot) is calculated.
                                  Only the best ones (with most matches) are
                                  used in the alignment. This parameter
                                  specifies how many. Decrease for speed;
                                  increase for sensitivity. (Positive integer)
*  -window             integer    [5 for protein, 4 for nucleic] This is the
                                  number of diagonals around each of the
                                  'best' diagonals that will be used. Decrease
                                  for speed; increase for sensitivity.
                                  (Positive integer)
*  -nopercent          boolean    [N] Fast pairwise alignment: similarity
                                  scores: suppresses percentage score
   -gapopen            float      [10.0] The penalty for opening a gap in the
                                  alignment. Increasing the gap opening
                                  penalty will make gaps less frequent.
                                  (Positive floating point number)
   -gapextend          float      [5.0] The penalty for extending a gap by 1
                                  residue. Increasing the gap extension
                                  penalty will make gaps shorter. Terminal
                                  gaps are not penalised. (Positive floating
                                  point number)
   -[no]endgaps        boolean    [Y] End gap separation: treats end gaps just
                                  like internal gaps for the purposes of
                                  avoiding gaps that are too close (set by
                                  'gap separation distance'). If you turn this
                                  off, end gaps will be ignored for this
                                  purpose. This is useful when you wish to
                                  align fragments where the end gaps are not
                                  biologically meaningful.
   -gapdist            integer    [8] Gap separation distance: tries to
                                  decrease the chances of gaps being too close
                                  to each other. Gaps that are less than this
                                  distance apart are penalised more than
                                  other gaps. This does not prevent close
                                  gaps; it makes them less frequent, promoting
                                  a block-like appearance of the alignment.
                                  (Positive integer)
*  -norgap             boolean    [N] Residue specific penalties: amino acid
                                  specific gap penalties that reduce or
                                  increase the gap opening penalties at each
                                  position in the alignment or sequence. As an
                                  example, positions that are rich in glycine
                                  are more likely to have an adjacent gap
                                  than positions that are rich in valine.
*  -hgapres            string     [GPSNDQEKR] This is a set of the residues
                                  'considered' to be hydrophilic. It is used
                                  when introducing Hydrophilic gap penalties.
                                  (Any string)
*  -nohgap             boolean    [N] Hydrophilic gap penalties: used to
                                  increase the chances of a gap within a run
                                  (5 or more residues) of hydrophilic amino
                                  acids; these are likely to be loop or random
                                  coil regions where gaps are more common.
                                  The residues that are 'considered' to be
                                  hydrophilic are set by '-hgapres'.
   -maxdiv             integer    [30] This switch, delays the alignment of
                                  the most distantly related sequences until
                                  after the most closely related sequences
                                  have been aligned. The setting shows the
                                  percent identity level required to delay the
                                  addition of a sequence; sequences that are
                                  less identical than this level to any other
                                  sequences will be aligned later. (Integer
                                  from 0 to 100)

   Advanced (Unprompted) qualifiers: (none)
   Associated qualifiers:

   "-sequence" associated qualifiers
   -sbegin1            integer    Start of each sequence to be used
   -send1              integer    End of each 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
   -scircular1         boolean    Sequence is circular
   -squick1            boolean    Read id and sequence only
   -sformat1           string     Input sequence format
   -iquery1            string     Input query fields or ID list
   -ioffset1           integer    Input start position offset
   -sdbname1           string     Database name
   -sid1               string     Entryname
   -ufo1               string     UFO features
   -fformat1           string     Features format
   -fopenfile1         string     Features file name

   "-outseq" associated qualifiers
   -osformat2          string     Output seq format
   -osextension2       string     File name extension
   -osname2            string     Base file name
   -osdirectory2       string     Output directory
   -osdbname2          string     Database name to add
   -ossingle2          boolean    Separate file for each entry
   -oufo2              string     UFO features
   -offormat2          string     Features format
   -ofname2            string     Features file name
   -ofdirectory2       string     Output directory

   "-dendoutfile" associated qualifiers
   -odirectory3        string     Output directory

   General qualifiers:
   -auto               boolean    Turn off prompts
   -stdout             boolean    Write first file to standard output
   -filter             boolean    Read first file from standard input, write
                                  first file to 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 and exit. 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 dying program messages
   -version            boolean    Report version number and exit

</pre>
</td></tr></table>
<P>
<table border cellspacing=0 cellpadding=3 bgcolor="#ccccff">
<tr bgcolor="#FFFFCC">
<th align="left">Qualifier</th>
<th align="left">Type</th>
<th align="left">Description</th>
<th align="left">Allowed values</th>
<th align="left">Default</th>
</tr>

<tr bgcolor="#FFFFCC">
<th align="left" colspan=5>Standard (Mandatory) qualifiers</th>
</tr>

<tr bgcolor="#FFFFCC">
<td>[-sequence]<br>(Parameter 1)</td>
<td>seqall</td>
<td>(Gapped) sequence(s) filename and optional format, or reference (input USA)</td>
<td>Readable sequence(s)</td>
<td><b>Required</b></td>
</tr>

<tr bgcolor="#FFFFCC">
<td>[-outseq]<br>(Parameter 2)</td>
<td>seqoutset</td>
<td>Sequence set filename and optional format (output USA)</td>
<td>Writeable sequences</td>
<td><i>&lt;*&gt;</i>.<i>format</i></td>
</tr>

<tr bgcolor="#FFFFCC">
<td>[-dendoutfile]<br>(Parameter 3)</td>
<td>outfile</td>
<td>Dendrogram (tree file) from clustalw output file</td>
<td>Output file</td>
<td><i>&lt;*&gt;</i>.emma</td>
</tr>

<tr bgcolor="#FFFFCC">
<th align="left" colspan=5>Additional (Optional) qualifiers</th>
</tr>

<tr bgcolor="#FFFFCC">
<td>-onlydend</td>
<td>toggle</td>
<td>Only produce dendrogram file</td>
<td>Toggle value Yes/No</td>
<td>No</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-dendreuse</td>
<td>toggle</td>
<td>Do alignment using an old dendrogram</td>
<td>Toggle value Yes/No</td>
<td>No</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-dendfile</td>
<td>infile</td>
<td>Dendrogram (tree file) from clustalw file (optional)</td>
<td>Input file</td>
<td><b>Required</b></td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-[no]slowalign</td>
<td>toggle</td>
<td>A distance is calculated between every pair of sequences and these are used to construct the dendrogram which guides the final multiple alignment. The scores are calculated from separate pairwise alignments. These can be calculated using 2 methods: dynamic programming (slow but accurate) or by the method of Wilbur and Lipman (extremely fast but approximate).
The slow-accurate method is fine for short sequences but will be VERY SLOW for many (e.g. &gt;100) long (e.g. &gt;1000 residue) sequences.</td>
<td>Toggle value Yes/No</td>
<td>Yes</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-pwmatrix</td>
<td>list</td>
<td>The scoring table which describes the similarity of each amino acid to each other.
There are three 'in-built' series of weight matrices offered. Each consists of several matrices which work differently at different evolutionary distances. To see the exact details, read the documentation. Crudely, we store several matrices in memory, spanning the full range of amino acid distance (from almost identical sequences to highly divergent ones). For very similar sequences, it is best to use a strict weight matrix which only gives a high score to identities and the most favoured conservative substitutions. For more divergent sequences, it is appropriate to use 'softer' matrices which give a high score to many other frequent substitutions.
1) BLOSUM (Henikoff). These matrices appear to be the best available for carrying out data base similarity (homology searches). The matrices used are: Blosum80, 62, 45 and 30.
2) PAM (Dayhoff). These have been extremely widely used since the late '70s. We use the PAM 120, 160, 250 and 350 matrices.
3) GONNET . These matrices were derived using almost the same procedure as the Dayhoff one (above) but are much more up to date and are based on a far larger data set. They appear to be more sensitive than the Dayhoff series. We use the GONNET 40, 80, 120, 160, 250 and 350 matrices.
We also supply an identity matrix which gives a score of 1.0 to two identical amino acids and a score of zero otherwise. This matrix is not very useful.</td>
<td><table><tr><td>b</td> <td><i>(blosum)</i></td></tr><tr><td>p</td> <td><i>(pam)</i></td></tr><tr><td>g</td> <td><i>(gonnet)</i></td></tr><tr><td>i</td> <td><i>(id)</i></td></tr><tr><td>o</td> <td><i>(own)</i></td></tr></table></td>
<td>b</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-pwdnamatrix</td>
<td>list</td>
<td>The scoring table which describes the scores assigned to matches and mismatches (including IUB ambiguity codes).</td>
<td><table><tr><td>i</td> <td><i>(iub)</i></td></tr><tr><td>c</td> <td><i>(clustalw)</i></td></tr><tr><td>o</td> <td><i>(own)</i></td></tr></table></td>
<td>i</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-pairwisedatafile</td>
<td>infile</td>
<td>Comparison matrix file (optional)</td>
<td>Input file</td>
<td><b>Required</b></td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-matrix</td>
<td>list</td>
<td>This gives a menu where you are offered a choice of weight matrices. The default for proteins is the PAM series derived by Gonnet and colleagues. Note, a series is used! The actual matrix that is used depends on how similar the sequences to be aligned at this alignment step are. Different matrices work differently at each evolutionary distance.
There are three 'in-built' series of weight matrices offered. Each consists of several matrices which work differently at different evolutionary distances. To see the exact details, read the documentation. Crudely, we store several matrices in memory, spanning the full range of amino acid distance (from almost identical sequences to highly divergent ones). For very similar sequences, it is best to use a strict weight matrix which only gives a high score to identities and the most favoured conservative substitutions. For more divergent sequences, it is appropriate to use 'softer' matrices which give a high score to many other frequent substitutions.
1) BLOSUM (Henikoff). These matrices appear to be the best available for carrying out data base similarity (homology searches). The matrices used are: Blosum80, 62, 45 and 30.
2) PAM (Dayhoff). These have been extremely widely used since the late '70s. We use the PAM 120, 160, 250 and 350 matrices.
3) GONNET . These matrices were derived using almost the same procedure as the Dayhoff one (above) but are much more up to date and are based on a far larger data set. They appear to be more sensitive than the Dayhoff series. We use the GONNET 40, 80, 120, 160, 250 and 350 matrices.
We also supply an identity matrix which gives a score of 1.0 to two identical amino acids and a score of zero otherwise. This matrix is not very useful. Alternatively, you can read in your own (just one matrix, not a series).</td>
<td><table><tr><td>b</td> <td><i>(blosum)</i></td></tr><tr><td>p</td> <td><i>(pam)</i></td></tr><tr><td>g</td> <td><i>(gonnet)</i></td></tr><tr><td>i</td> <td><i>(id)</i></td></tr><tr><td>o</td> <td><i>(own)</i></td></tr></table></td>
<td>b</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-dnamatrix</td>
<td>list</td>
<td>This gives a menu where a single matrix (not a series) can be selected.</td>
<td><table><tr><td>i</td> <td><i>(iub)</i></td></tr><tr><td>c</td> <td><i>(clustalw)</i></td></tr><tr><td>o</td> <td><i>(own)</i></td></tr></table></td>
<td>i</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-mamatrixfile</td>
<td>infile</td>
<td>Comparison matrix file (optional)</td>
<td>Input file</td>
<td><b>Required</b></td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-pwgapopen</td>
<td>float</td>
<td>The penalty for opening a gap in the pairwise alignments.</td>
<td>Number 0.000 or more</td>
<td>10.0</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-pwgapextend</td>
<td>float</td>
<td>The penalty for extending a gap by 1 residue in the pairwise alignments.</td>
<td>Number 0.000 or more</td>
<td>0.1</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-ktup</td>
<td>integer</td>
<td>This is the size of exactly matching fragment that is used. INCREASE for speed (max= 2 for proteins; 4 for DNA), DECREASE for sensitivity. For longer sequences (e.g. &gt;1000 residues) you may need to increase the default.</td>
<td>integer from 0 to 4</td>
<td>1 for protein, 2 for nucleic</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-gapw</td>
<td>integer</td>
<td>This is a penalty for each gap in the fast alignments. It has little affect on the speed or sensitivity except for extreme values.</td>
<td>Positive integer</td>
<td>3 for protein, 5 for nucleic</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-topdiags</td>
<td>integer</td>
<td>The number of k-tuple matches on each diagonal (in an imaginary dot-matrix plot) is calculated. Only the best ones (with most matches) are used in the alignment. This parameter specifies how many. Decrease for speed; increase for sensitivity.</td>
<td>Positive integer</td>
<td>5 for protein, 4 for nucleic</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-window</td>
<td>integer</td>
<td>This is the number of diagonals around each of the 'best' diagonals that will be used. Decrease for speed; increase for sensitivity.</td>
<td>Positive integer</td>
<td>5 for protein, 4 for nucleic</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-nopercent</td>
<td>boolean</td>
<td>Fast pairwise alignment: similarity scores: suppresses percentage score</td>
<td>Boolean value Yes/No</td>
<td>No</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-gapopen</td>
<td>float</td>
<td>The penalty for opening a gap in the alignment. Increasing the gap opening penalty will make gaps less frequent.</td>
<td>Positive floating point number</td>
<td>10.0</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-gapextend</td>
<td>float</td>
<td>The penalty for extending a gap by 1 residue. Increasing the gap extension penalty will make gaps shorter. Terminal gaps are not penalised.</td>
<td>Positive floating point number</td>
<td>5.0</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-[no]endgaps</td>
<td>boolean</td>
<td>End gap separation: treats end gaps just like internal gaps for the purposes of avoiding gaps that are too close (set by 'gap separation distance'). If you turn this off, end gaps will be ignored for this purpose. This is useful when you wish to align fragments where the end gaps are not biologically meaningful.</td>
<td>Boolean value Yes/No</td>
<td>Yes</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-gapdist</td>
<td>integer</td>
<td>Gap separation distance: tries to decrease the chances of gaps being too close to each other. Gaps that are less than this distance apart are penalised more than other gaps. This does not prevent close gaps; it makes them less frequent, promoting a block-like appearance of the alignment.</td>
<td>Positive integer</td>
<td>8</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-norgap</td>
<td>boolean</td>
<td>Residue specific penalties: amino acid specific gap penalties that reduce or increase the gap opening penalties at each position in the alignment or sequence. As an example, positions that are rich in glycine are more likely to have an adjacent gap than positions that are rich in valine.</td>
<td>Boolean value Yes/No</td>
<td>No</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-hgapres</td>
<td>string</td>
<td>This is a set of the residues 'considered' to be hydrophilic. It is used when introducing Hydrophilic gap penalties.</td>
<td>Any string</td>
<td>GPSNDQEKR</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-nohgap</td>
<td>boolean</td>
<td>Hydrophilic gap penalties: used to increase the chances of a gap within a run (5 or more residues) of hydrophilic amino acids; these are likely to be loop or random coil regions where gaps are more common. The residues that are 'considered' to be hydrophilic are set by '-hgapres'.</td>
<td>Boolean value Yes/No</td>
<td>No</td>
</tr>

<tr bgcolor="#FFFFCC">
<td>-maxdiv</td>
<td>integer</td>
<td>This switch, delays the alignment of the most distantly related sequences until after the most closely related sequences have been aligned. The setting shows the percent identity level required to delay the addition of a sequence; sequences that are less identical than this level to any other sequences will be aligned later.</td>
<td>Integer from 0 to 100</td>
<td>30</td>
</tr>

<tr bgcolor="#FFFFCC">
<th align="left" colspan=5>Advanced (Unprompted) qualifiers</th>
</tr>

<tr>
<td colspan=5>(none)</td>
</tr>

<tr bgcolor="#FFFFCC">
<th align="left" colspan=5>Associated qualifiers</th>
</tr>

<tr bgcolor="#FFFFCC">
<td align="left" colspan=5>"-sequence" associated seqall qualifiers
</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sbegin1<br>-sbegin_sequence</td>
<td>integer</td>
<td>Start of each sequence to be used</td>
<td>Any integer value</td>
<td>0</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -send1<br>-send_sequence</td>
<td>integer</td>
<td>End of each sequence to be used</td>
<td>Any integer value</td>
<td>0</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sreverse1<br>-sreverse_sequence</td>
<td>boolean</td>
<td>Reverse (if DNA)</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sask1<br>-sask_sequence</td>
<td>boolean</td>
<td>Ask for begin/end/reverse</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -snucleotide1<br>-snucleotide_sequence</td>
<td>boolean</td>
<td>Sequence is nucleotide</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sprotein1<br>-sprotein_sequence</td>
<td>boolean</td>
<td>Sequence is protein</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -slower1<br>-slower_sequence</td>
<td>boolean</td>
<td>Make lower case</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -supper1<br>-supper_sequence</td>
<td>boolean</td>
<td>Make upper case</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -scircular1<br>-scircular_sequence</td>
<td>boolean</td>
<td>Sequence is circular</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -squick1<br>-squick_sequence</td>
<td>boolean</td>
<td>Read id and sequence only</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sformat1<br>-sformat_sequence</td>
<td>string</td>
<td>Input sequence format</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -iquery1<br>-iquery_sequence</td>
<td>string</td>
<td>Input query fields or ID list</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -ioffset1<br>-ioffset_sequence</td>
<td>integer</td>
<td>Input start position offset</td>
<td>Any integer value</td>
<td>0</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sdbname1<br>-sdbname_sequence</td>
<td>string</td>
<td>Database name</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -sid1<br>-sid_sequence</td>
<td>string</td>
<td>Entryname</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -ufo1<br>-ufo_sequence</td>
<td>string</td>
<td>UFO features</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -fformat1<br>-fformat_sequence</td>
<td>string</td>
<td>Features format</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -fopenfile1<br>-fopenfile_sequence</td>
<td>string</td>
<td>Features file name</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td align="left" colspan=5>"-outseq" associated seqoutset qualifiers
</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -osformat2<br>-osformat_outseq</td>
<td>string</td>
<td>Output seq format</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -osextension2<br>-osextension_outseq</td>
<td>string</td>
<td>File name extension</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -osname2<br>-osname_outseq</td>
<td>string</td>
<td>Base file name</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -osdirectory2<br>-osdirectory_outseq</td>
<td>string</td>
<td>Output directory</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -osdbname2<br>-osdbname_outseq</td>
<td>string</td>
<td>Database name to add</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -ossingle2<br>-ossingle_outseq</td>
<td>boolean</td>
<td>Separate file for each entry</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -oufo2<br>-oufo_outseq</td>
<td>string</td>
<td>UFO features</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -offormat2<br>-offormat_outseq</td>
<td>string</td>
<td>Features format</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -ofname2<br>-ofname_outseq</td>
<td>string</td>
<td>Features file name</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -ofdirectory2<br>-ofdirectory_outseq</td>
<td>string</td>
<td>Output directory</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<td align="left" colspan=5>"-dendoutfile" associated outfile qualifiers
</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -odirectory3<br>-odirectory_dendoutfile</td>
<td>string</td>
<td>Output directory</td>
<td>Any string</td>
<td>&nbsp;</td>
</tr>

<tr bgcolor="#FFFFCC">
<th align="left" colspan=5>General qualifiers</th>
</tr>

<tr bgcolor="#FFFFCC">
<td> -auto</td>
<td>boolean</td>
<td>Turn off prompts</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -stdout</td>
<td>boolean</td>
<td>Write first file to standard output</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -filter</td>
<td>boolean</td>
<td>Read first file from standard input, write first file to standard output</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -options</td>
<td>boolean</td>
<td>Prompt for standard and additional values</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -debug</td>
<td>boolean</td>
<td>Write debug output to program.dbg</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -verbose</td>
<td>boolean</td>
<td>Report some/full command line options</td>
<td>Boolean value Yes/No</td>
<td>Y</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -help</td>
<td>boolean</td>
<td>Report command line options and exit. More information on associated and general qualifiers can be found with -help -verbose</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -warning</td>
<td>boolean</td>
<td>Report warnings</td>
<td>Boolean value Yes/No</td>
<td>Y</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -error</td>
<td>boolean</td>
<td>Report errors</td>
<td>Boolean value Yes/No</td>
<td>Y</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -fatal</td>
<td>boolean</td>
<td>Report fatal errors</td>
<td>Boolean value Yes/No</td>
<td>Y</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -die</td>
<td>boolean</td>
<td>Report dying program messages</td>
<td>Boolean value Yes/No</td>
<td>Y</td>
</tr>

<tr bgcolor="#FFFFCC">
<td> -version</td>
<td>boolean</td>
<td>Report version number and exit</td>
<td>Boolean value Yes/No</td>
<td>N</td>
</tr>

</table>

<H2>
    Input file format
</H2>

The input is two or more sequences.

<p>

<a name="input.1"></a>
<h3>Input files for usage example </h3>
<p><h3>File: globins.fasta</h3>
<table width="90%"><tr><td bgcolor="#FFCCFF">
<pre>
&gt;HBB_HUMAN Sw:Hbb_Human =&gt; HBB_HUMAN
VHLTPEEKSAVTALWGKVNVDEVGGEALGRLLVVYPWTQRFFESFGDLSTPDAVMGNPKV
KAHGKKVLGAFSDGLAHLDNLKGTFATLSELHCDKLHVDPENFRLLGNVLVCVLAHHFGK
EFTPPVQAAYQKVVAGVANALAHKYH
&gt;HBB_HORSE Sw:Hbb_Horse =&gt; HBB_HORSE
VQLSGEEKAAVLALWDKVNEEEVGGEALGRLLVVYPWTQRFFDSFGDLSNPGAVMGNPKV
KAHGKKVLHSFGEGVHHLDNLKGTFAALSELHCDKLHVDPENFRLLGNVLVVVLARHFGK
DFTPELQASYQKVVAGVANALAHKYH
&gt;HBA_HUMAN Sw:Hba_Human =&gt; HBA_HUMAN
VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHFDLSHGSAQVKGHGK
KVADALTNAVAHVDDMPNALSALSDLHAHKLRVDPVNFKLLSHCLLVTLAAHLPAEFTPA
VHASLDKFLASVSTVLTSKYR
&gt;HBA_HORSE Sw:Hba_Horse =&gt; HBA_HORSE
VLSAADKTNVKAAWSKVGGHAGEYGAEALERMFLGFPTTKTYFPHFDLSHGSAQVKAHGK
KVGDALTLAVGHLDDLPGALSNLSDLHAHKLRVDPVNFKLLSHCLLSTLAVHLPNDFTPA
VHASLDKFLSSVSTVLTSKYR
&gt;MYG_PHYCA Sw:Myg_Phyca =&gt; MYG_PHYCA
VLSEGEWQLVLHVWAKVEADVAGHGQDILIRLFKSHPETLEKFDRFKHLKTEAEMKASED
LKKHGVTVLTALGAILKKKGHHEAELKPLAQSHATKHKIPIKYLEFISEAIIHVLHSRHP
GDFGADAQGAMNKALELFRKDIAAKYKELGYQG
&gt;GLB5_PETMA Sw:Glb5_Petma =&gt; GLB5_PETMA
PIVDTGSVAPLSAAEKTKIRSAWAPVYSTYETSGVDILVKFFTSTPAAQEFFPKFKGLTT
ADQLKKSADVRWHAERIINAVNDAVASMDDTEKMSMKLRDLSGKHAKSFQVDPQYFKVLA
AVIADTVAAGDAGFEKLMSMICILLRSAY
&gt;LGB2_LUPLU Sw:Lgb2_Luplu =&gt; LGB2_LUPLU
GALTESQAALVKSSWEEFNANIPKHTHRFFILVLEIAPAAKDLFSFLKGTSEVPQNNPEL
QAHAGKVFKLVYEAAIQLQVTGVVVTDATLKNLGSVHVSKGVADAHFPVVKEAILKTIKE
VVGAKWSEELNSAWTIAYDELAIVIKKEMNDAA
</pre>
</td></tr></table><p>
<p>

EMBOSS programs do not allow you to simply type the names of two or more
files or database entries - they try to interpret this as all one
file-name and complain that a file of that name does not exist. 

<p>

In order to enter the sequences that you wish to align, you must group
them in one of three ways: either make a 'list file' or place several
sequences in a single sequence file or specify the sequences using
wildcards. 

<p>


<H3>Making a List file</H3>

A list file is a text file that holds the names of database entries
and/or sequence files. 

<p>

You should use a text editor such as <b>pico</b> or <b>nedit</b> to edit
a file to contain the names of the sequence files or database entries. 
There must be one sequence per line. 

<p>

An example is the file 'fred' which contains:

<p>
<pre>
<hr>
opsd_abyko.fasta
sw:opsd_xenla
sw:opsd_c*
@another_list
<hr>
</pre>
<p>

This List files contains:

<p>
<ul>

<li>opsd_abyko.fasta - this is the name of a sequence file. The file
is read in from the current directory.

<li>sw:opsd_xenla - this is a reference to a specific sequence in the
SwissProt database

<li>sw:opsd_c* - this represents all the sequences in SwissProt whose
identifiers start with ``opsd_c''

<li>another_list - this is the name of a second list file. List files
can be nested!

</ul>
<p>

Notice the @ in front of the last entry.  This is the way you tell
EMBOSS that this file is a List file, not a regular sequence file.  That
last line was put there both as an indication of the way you tell EMBOSS
that a file is a List file and to emphasise that List files can contain
other List files. 

<p>

When <b>emma</b> asks for the sequences to align, you should type
'@fred'.  The '@' character tells EMBOSS that this is the name
of a List file.

<p>

An alternative to editing a file and laboriously typing in all of the
names you require is to make a list of a directory containing the
sequence files and then to edit the list file to remove the names of the
sequences files than you do not require. 

<p>

To make a list of all the files in the current directory that end in
'.pep', type:

<p>

ls *.pep &gt; listfile

<H3>Several sequences in one file</H3>

EMBOSS can read in a single file which contains many sequences.

<p>

Each of the sequences in the file must be in the same format - if the
first sequence is in EMBL format, then all the others must be in EMBL
format. 

<p>

There are some sequence formats that cannot be used when placing many
sequences in the same file.  These are sequence formats that have no
clear indication of where the sequence ends and the annotation of the
next sequence starts.  These formats include: plain or text format (no
real format, just the sequence), staden, gcg. 

<p>

If your sequences are not already in a single file, you can place them
in one using <b>seqret</b>.  The following example takes all the files
ending in '.pep' and places them in the file 'mystuff' in Fasta format. 

<p>

seqret "*.pep" mystuff

<p>

When <b>emma</b> asks for the sequences to align, you should type
'mystuff'.

<H3>Using wildcards</H3>

'Wildcard' characters are characters that are expanded to match all
possible matching files or entries in a database. 

<p>

By far the most commonly used wildcard character is '*' which matches
any number (or zero) of possible characters at that position in the name. 

<p>

A less commonly used wildcard character is '?' which matches any one
character at that position. 

<p>

For example, when <b>emma</b> asks for sequences to align, you could answer:
<br>
abc*.pep

This would select any files whose name starts with 'abc' and then ends
in '.pep'; the centre of the name where there is a '*' can be anything. 

<p>

Both file names and database entry names can be wildcarded.

<p>

There is a slightly irritating problem that occurs when wildcards are
used one the Unix command line (This is the line that you type against
the 'Unix' prompt together with the program name.)

<p>

In this case the Unix session gets the command line first, runs the
program, expands the wildcards and passes the program parameters to the
program.  When Unix expands the wildcards, two things go wrong.  You may
have specified wildcarded database entries - the Unix system tries to
file files that match that specification, it fails and refuses to run
the program.  Alternatively, you may have specified wildcarded files -
Unix fileds them and gives the name of each of them to the program as a
separate parameter - emma gets the wrong number of parameters and
refuses to run. 

<p>

You get round this by quoting the wildcard.  You can either put the
whole wildcarded name in quotes:

<br>
"abc*.pep"
<br>

or you can quote just the '*' using a '\' as:
<br>
abc\*.pep
<br>  

<p>

This problem does not occur when you reply to the prompt from the
program for the input sequences, or when you are typing the wildcard
files name in a web browser of GUI (such as Jemboss or SPIN) field

<H2>
    Output file format
</H2>


<a name="output.1"></a>
<h3>Output files for usage example </h3>
<p><h3>File: hbb_human.aln</h3>
<table width="90%"><tr><td bgcolor="#CCFFCC">
<pre>
&gt;HBB_HUMAN
--------VHLTPEEKSAVTALWGKVN--VDEVGGEALGRLLVVYPWTQRFFESFGDLST
PDAVMGNPKVKAHGKKVLGAFSDGLAHLDNLKGTFATLSELHCDKLHVDP----ENFRLL
GNVLVCVLAHHFGKEFTPPVQAAYQKVVAGVANALAHKYH------
&gt;HBB_HORSE
--------VQLSGEEKAAVLALWDKVN--EEEVGGEALGRLLVVYPWTQRFFDSFGDLSN
PGAVMGNPKVKAHGKKVLHSFGEGVHHLDNLKGTFAALSELHCDKLHVDP----ENFRLL
GNVLVVVLARHFGKDFTPELQASYQKVVAGVANALAHKYH------
&gt;HBA_HUMAN
---------VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHF-----
-DLSHGSAQVKGHGKKVADALTNAVAHVDDMPNALSALSDLHAHKLRVDP----VNFKLL
SHCLLVTLAAHLPAEFTPAVHASLDKFLASVSTVLTSKYR------
&gt;HBA_HORSE
---------VLSAADKTNVKAAWSKVGGHAGEYGAEALERMFLGFPTTKTYFPHF-----
-DLSHGSAQVKAHGKKVGDALTLAVGHLDDLPGALSNLSDLHAHKLRVDP----VNFKLL
SHCLLSTLAVHLPNDFTPAVHASLDKFLSSVSTVLTSKYR------
&gt;MYG_PHYCA
---------VLSEGEWQLVLHVWAKVEADVAGHGQDILIRLFKSHPETLEKFDRFKHLKT
EAEMKASEDLKKHGVTVLTALGAILKKKGHHEAELKPLAQSHATKHKIPI----KYLEFI
SEAIIHVLHSRHPGDFGADAQGAMNKALELFRKDIAAKYKELGYQG
&gt;GLB5_PETMA
PIVDTGSVAPLSAAEKTKIRSAWAPVYSTYETSGVDILVKFFTSTPAAQEFFPKFKGLTT
ADQLKKSADVRWHAERIINAVNDAVASMDDTEKMSMKLRDLSGKHAKSFQ----VDPQYF
KVLAAVIADTVAAGDAGFEKLMSMICILLRSAY-------------
&gt;LGB2_LUPLU
--------GALTESQAALVKSSWEEFNANIPKHTHRFFILVLEIAPAAKDLFSFLKG--T
SEVPQNNPELQAHAGKVFKLVYEAAIQLQVTGVVVTDATLKNLGSVHVSKGVADAHFPVV
KEAILKTIKEVVGAKWSEELNSAWTIAYDELAIVIKKEMNDAA---
</pre>
</td></tr></table><p>
<p><h3>File: hbb_human.dnd</h3>
<table width="90%"><tr><td bgcolor="#CCFFCC">
<pre>
(
(
(
(
HBB_HUMAN:0.08080,
HBB_HORSE:0.08359)
:0.21952,
(
HBA_HUMAN:0.05452,
HBA_HORSE:0.06605)
:0.21070)
:0.06034,
MYG_PHYCA:0.39882)
:0.01490,
GLB5_PETMA:0.38267,
LGB2_LUPLU:0.50324);
</pre>
</td></tr></table><p>
<p>

<h3>Sequences</h3>

<b>emma</b> writes the aligned sequences and a dendrogram file showing how
the sequences were clustered during the progressive alignments.

<p>

The clustalw output sequences are reformatted into the default EMBOSS
output format instead of being left as Clustal-format '.aln' files. 


<h3>Trees</h3>

Believe it or not, we now use the New Hampshire (nested parentheses)
format as default for our trees.  This format is compatible with e.g. the
PHYLIP package.  If you want to view a tree, you can use the RETREE or 
DRAWGRAM/DRAWTREE programs of PHYLIP.  This format is used for all our 
trees, even the initial guide trees for deciding the order of multiple
alignment.  The output trees from the phylogenetic tree menu can also be
requested in our old verbose/cryptic format.  This may be more useful
if, for example, you wish to see the bootstrap figures.  The bootstrap
trees in the default New Hampshire format give the bootstrap figures
as extra labels which can be viewed very easily using TREETOOL which is
available as part of the GDE package.  TREETOOL is available from the
RDP project by ftp from rdp.life.uiuc.edu.  

<p>

The New Hampshire format is only useful if you have software to display
or manipulate the trees.  The PHYLIP package is highly recommended if
you intend to do much work with trees and includes programs for doing
this.  WE DO NOT PROVIDE ANY DIRECT MEANS FOR VIEWING TREES GRAPHICALLY. 



<H2>
    Data files
</H2>


The comparison matrices available for clustalw are not EMBOSS matrix
files, as they are defined in the clustalw code. The matrices
available for carrying out a protein sequence alignment are:

<ul>

<li>blosum

<li>pam

<li>gonnet

<li>id

<li>user defined

</ul>

The comparison matrices available in clustalw for carrying out a
nucleotide sequence alignment are:

<ul>

<li>iub

<li>clustalw

<li>user defined

</ul>


<H2>
    Notes
</H2>

<h3>The basic alignment method</h3>

The basic multiple alignment algorithm consists of three main stages: 1) all 
pairs of sequences are aligned separately in order to calculate a distance matrix 
giving the divergence of each pair of sequences; 2) a guide tree is calculated 
from the distance matrix; 3) the sequences are progressively aligned according 
to the branching order in the guide tree.   An example using 7 globin 
sequences of known tertiary structure (25) is given in figure 1.


<h4>1) The distance matrix/pairwise alignments</h4>

In the original CLUSTAL programs, the pairwise distances were calculated 
using a fast approximate method (22).   This allows very large numbers of 
sequences to be aligned, even on a microcomputer.   The scores are calculated 
as the number of k-tuple matches (runs of identical residues, typically 1 or 2 
long for proteins or 2 to 4 long for nucleotide sequences) in the best alignment 
between two sequences minus a fixed penalty for every gap.   We now offer a 
choice between this method and the slower but more accurate scores from full 
dynamic programming alignments using two gap penalties (for opening or 
extending gaps) and a full amino acid weight matrix.   These scores are 
calculated as the number of identities in the best alignment divided by the 
number of residues compared (gap positions are excluded).   Both of these 
scores are initially calculated as percent identity scores and are converted to 
distances by dividing by 100 and subtracting from 1.0 to give number of 
differences per site.   We do not correct for multiple substitutions in these 
initial distances.   In figure 1 we give the 7x7 distance matrix between the 7 
globin sequences calculated using the full dynamic programming method.


<h4>2) The guide tree</h4>

The trees used to guide the final multiple alignment process are calculated 
from the distance matrix of step 1 using the Neighbour-Joining method (21).   
This produces unrooted trees with branch lengths proportional to estimated 
divergence along each branch.   The root is placed by a "mid-point" method 
(15) at a position where the means of the branch lengths on either side of the 
root are equal.   These trees are also used to derive a weight for each sequence 
(15).   The weights are dependent upon the distance from the root of the tree 
but sequences which have a common branch with other sequences share the 
weight derived from the shared branch.   In the example in figure 1, the 
leghaemoglobin (Lgb2_Luplu) gets a weight of 0.442 which is equal to the 
length of the branch from the root to it.  The Human beta globin 
(Hbb_Human) gets a weight consisting of the length of the branch leading to 
it that is not shared with any other sequences (0.081) plus half the length of 
the branch shared with the horse beta globin (0.226/2) plus one quarter the 
length of the branch shared by all four haemoglobins (0.061/4) plus one fifth 
the branch shared between the haemoglobins and the myoglobin (0.015/5) 
plus one sixth the branch leading to all the vertebrate globins (0.062).  This 
sums to a total of 0.221.  By contrast, in the normal progressive alignment 
algorithm, all sequences would be equally weighted.  The rooted tree with 
branch lengths and sequence weights for the 7 globins is given in figure 1.  


<h4>3) Progressive alignment</h4>

The basic procedure at this stage is to use a series of pairwise alignments to 
align larger and larger groups of sequences, following the branching order in 
the guide tree.   You proceed from the tips of the rooted tree towards the root.

<p>
   
In the globin example in figure 1 you align the sequences in the following 
order: human vs. horse beta globin; human vs. horse alpha globin; the 2 
alpha globins vs. the 2 beta globins; the myoglobin vs. the haemoglobins; the 
cyanohaemoglobin vs the haemoglobins plus myoglobin; the leghaemoglobin 
vs. all the rest.  At each stage a full dynamic programming (26,27) algorithm is 
used with a residue weight matrix and penalties for opening and extending 
gaps.   Each step consists of aligning two existing alignments or sequences.  
Gaps that are present in older alignments remain fixed.  In the basic 
algorithm, new gaps that are introduced at each stage get full gap opening and 
extension penalties, even if they are introduced inside old gap positions (see 
the section on gap penalties below for modifications to this rule).  In order to 
calculate the score between a position from one sequence or alignment and 
one from another, the average of all the pairwise weight matrix scores from 
the amino acids in the two sets of sequences is used i.e. if you align 2 
alignments with 2 and 4 sequences respectively, the score at each position is 
the average of 8 (2x4) comparisons.   This is illustrated in figure 2.  If either set 
of sequences contains one or more gaps in one of the positions being 
considered, each gap versus a residue is scored as zero.   The default amino 
acid weight matrices we use are rescored to have only positive values. 
Therefore, this treatment of gaps treats the score of a residue versus a gap as 
having the worst possible score.  When sequences are weighted (see 
improvements to progressive alignment, below), each weight matrix value is 
multiplied by the weights from the 2 sequences, as illustrated in figure 2.


<h4>Improvements to progressive alignment</h4>

All of the remaining modifications apply only to the final progressive 
alignment stage.   Sequence weighting is relatively straightforward and is 
already widely used in profile searches (15,16).   The treatment of gap penalties 
is more complicated.   Initial gap penalties are calculated depending on the 
weight matrix, the similarity of the sequences, and the length of the 
sequences. Then, an attempt is made to derive sensible local gap opening 
penalties at every position in each pre-aligned group of sequences that will 
vary as new sequences are added.   The use of different weight matrices as the 
alignment progresses is novel and largely by-passes the problem of initial 
choice of weight matrix.   The final modification allows us to delay the 
addition of very divergent sequences until the end of the alignment process 
when all of the more closely related sequences have already been aligned.


<h3>Sequence weighting</h3>

Sequence weights are calculated directly from the guide tree.    The weights 
are normalised such that the biggest one is set to 1.0 and the rest are all less 
than one.  Groups of closely related sequences receive lowered weights 
because they contain much duplicated information.  Highly divergent 
sequences without any close relatives receive high weights.  These weights 
are used as simple multiplication factors for scoring positions from different 
sequences or prealigned groups of sequences.  The method is illustrated in 
figure 2.  In the globin example in figure 1, the two alpha globins get 
downweighted because they are almost duplicate sequences (as do the two 
beta globins); they receive a combined weight of only slightly more than if a 
single alpha globin was used.   


<h3>Initial gap penalties</h3>

Initially, two gap penalties are used: a gap opening penalty (GOP) which gives 
the cost of opening a new gap of any length and a gap extension penalty (GEP) 
which gives the cost of every item in a gap.  Initial values can be set by the 
user from a menu.   The software then automatically attempts to choose 
appropriate gap penalties for each sequence alignment, depending on the 
following factors.

<h4>1) Dependence on the weight matrix</h4>

It has been shown (16,28) that varying the gap penalties used with different 
weight matrices can improve the accuracy of sequence alignments. Here, we 
use the average score for two mismatched residues (ie. off-diagonal values in 
the matrix) as a scaling factor for the GOP.

<h4>2) Dependence on the similarity of the sequences</h4>

The percent identity of the two (groups of) sequences to be aligned is used to 
increase the GOP for closely related sequences and decrease it for more 
divergent sequences on a linear scale.

<h4>3) Dependence on the lengths of the sequences</h4>

The scores for both true and false sequence alignments grow with the length 
of the sequences. We use the logarithm of the length of the shorter sequence 
to increase the GOP with sequence length.

<p>

Using these three modifications, the initial GOP calculated by the program is:

<p>

GOP->(GOP+log(MIN(N,M))) * (average residue mismatch score) *                                                               (percent identity scaling factor)
<br>
where N, M are the lengths of the two sequences.

<p>

<h4>4) Dependence on the difference in the lengths of the sequences</h4>

The GEP is modified depending on the difference between the lengths of the 
two sequences to be aligned. If one sequence is much shorter than the other, 
the GEP is increased to inhibit too many long gaps in the shorter sequence.
The initial GEP calculated by the program is:

<p>

GEP ->  GEP*(1.0+|log(N/M)|) 
<br>
where N, M are the lengths of the two sequences.


<h3>Position-specific gap penalties</h3>

 In most dynamic programming applications, the initial gap opening and 
extension penalties are applied equally at every position in the sequence, 
regardless of the location of a gap, except for terminal gaps which are usually 
allowed at no cost.   In CLUSTAL W, before any pair of sequences or 
prealigned groups of sequences are aligned, we generate a table of gap opening 
penalties for every position in the two (sets of) sequences.  An example is 
shown in figure 3.  We manipulate the initial gap opening penalty in a 
position specific manner, in order to make gaps more or less likely at different 
positions.   

<p>

The local gap penalty modification rules are applied in a hierarchical manner.  
 
<p>

The exact details of each rule are given below.  Firstly, if there is a gap at a
position, the gap opening and gap extension penalties are lowered; the other 
rules do not apply.   This makes gaps more likely at positions where there are 
already gaps.  If there is no gap at a position, then the gap opening penalty is
increased if the position is within 8 residues of an existing gap.   This 
discourages gaps that are too close together.  Finally, at any position within a
run of hydrophilic residues, the penalty is decreased.  These runs usually 
indicate loop regions in protein structures.  If there is no run of hydrophilic 
residues, the penalty is modified using a table of residue specific gap 
propensities (12).   These propensities were derived by counting the frequency 
of each residue at either end of gaps in alignments of proteins of known 
structure.  An illustration of the application of these rules from one part of 
the globin example, in figure 1, is given in figure 3.  

<h4>1) Lowered gap penalties at existing gaps</h4>

If there are already gaps at a position, then the GOP is reduced in proportion 
to the number of sequences with a gap at this position and the GEP is lowered 
by a half.  The new gap opening penalty is calculated as:

<p>

GOP ->  GOP*0.3*(no. of sequences without a gap/no. of sequences).

<h4>2) Increased gap penalties near existing gaps</h4>

If a position does not have any gaps but is within 8 residues of an existing gap, 
the GOP is increased by:

<p>

GOP ->  GOP*(2+((8-distance from gap)*2)/8)

<h4>3) Reduced gap penalties in hydrophilic stretches</h4>

Any run of 5 hydrophilic residues is considered to be a hydrophilic stretch.  
The residues that are to be considered hydrophilic may be set by the user but 
are conservatively set to D, E, G, K, N, Q, P, R or S by default.   If, at any 
position, there are no gaps and any of the sequences has such a stretch, the 
GOP is reduced by one third.


<h4>4) Residue specific penalties</h4>

If there is no hydrophilic stretch and the position does not contain any gaps, 
then the GOP is multiplied by one of the 20 numbers in table 1, depending on 
the residue.  If there is a mixture of residues at a position, the multiplication 
factor is the average of all the contributions from each sequence.  


<h3>Weight matrices</h3>

Two main series of weight matrices are offered to the user: the Dayhoff PAM 
series (3) and the BLOSUM series (4).   The default is the BLOSUM series.  In 
each case, there is a choice of matrix ranging from strict ones, useful for 
comparing very closely related sequences to very "soft" ones that are useful 
for comparing very distantly related sequences.   Depending on the distance 
between the two sequences or groups of sequences to be compared, we switch 
between 4 different matrices.  The distances are measured directly from the 
guide tree.  The ranges of distances and tables used with the PAM series of 
matrices is: 80-100%:PAM20, 60-80%:PAM60, 40-60%:PAM120, 0-40%:PAM350. 
The range used with the BLOSUM series is:80-100%:BLOSUM80,
60-80%:BLOSUM62, 30-60%:BLOSUM45, 0-30%:BLOSUM30.

<h3>Divergent sequences</h3>

The most divergent sequences (most different, on average from all of the 
other sequences) are usually the most difficult to align correctly.  It is 
sometimes better to delay the incorporation of these sequences until all of the 
more easily aligned sequences are merged first.  This may give a better chance 
of correctly placing the gaps and matching weakly conserved positions against 
the rest of the sequences.   A choice is offered to set a cut off (default is 40% 
identity or less with any other sequence) that will delay the alignment of the 
divergent sequences until all of the rest have been aligned.  


<h2>Software and Algorithms</h2>


<h3>Dynamic Programming</h3>

The most demanding part of the multiple alignment strategy, in terms of 
computer processing and memory usage, is the alignment of two (groups of) 
sequences at each step in the final progressive alignment.   To make it 
possible to align very long sequences (e.g. dynein heavy chains at ~ 5,000 
residues) in a reasonable amount of memory, we use the memory efficient 
dynamic programming algorithm of Myers and Miller (26).   This sacrifices 
some processing time but makes very large alignments practical in very little 
memory.   One disadvantage of this algorithm is that it does not allow 
different gap opening and extension penalties at each position.  We have 
modified the algorithm so as to allow this and the details are described in a 
separate paper (27).   


<h3>Alignment to an alignment</h3>

Profile alignment is used to align two existing alignments (either of which 
may consist of just one sequence) or to add a series of new sequences to an 
existing alignment.   This is useful because one may wish to build up a 
multiple alignment gradually, choosing different parameters manually, or 
correcting intermediate errors as the alignment proceeds.   Often, just a few 
sequences cause misalignments in the progressive algorithm and these can be 
removed from the process and then added at the end by profile alignment.  A 
second use is where one has a high quality reference alignment and wishes to 
keep it fixed while adding new sequences automatically.  


<!-- clustalw.doc documentation  -->

<h3>Terminal Gaps</h3>

In the original Clustal V program, terminal gaps were penalised the same
as all other gaps.  This caused some ugly side effects e.g.

<p>

<pre>
acgtacgtacgtacgt                              acgtacgtacgtacgt
a----cgtacgtacgt  gets the same score as      ----acgtacgtacgt
</pre>

<p>

NOW, terminal gaps are free.  This is better on average and stops silly
effects like single residues jumping to the edge of the alignment.  However,
it is not perfect.  It does mean that if there should be a gap near the end 
of the alignment, the program may be reluctant to insert it i.e. 

<p>
<pre>
cccccgggccccc                                              cccccgggccccc
ccccc---ccccc  may be considered worse (lower score) than  cccccccccc---
</pre>

<p>

In the right hand case above, the terminal gap is free and may score higher
than the laft hand alignment.  This can be prevented by lowering the gap
opening and extension penalties.   It is difficult to get this right all the
time.  Please watch the ends of your alignments. 



<h3>Speed of the initial (pairwise) alignments (fast approximate/slow accurate)</h3>

By default, the initial pairwise alignments are now carried out using a full
dynamic programming algorithm.  This is more accurate than the older hash/
k-tuple based alignments (Wilbur and Lipman) but is MUCH slower.  On a fast
workstation you may not notice but on a slow box, the difference is extreme.
You can set the alignment method from the menus easily to the older, faster
method.



<h3>Delaying alignment of distant sequences</h3>

The user can set a cut off to delay the alignment of the most divergent
sequences in a data set until all other sequences have been aligned.  By 
default, this is set to 40% which means that if a sequence is less than 40%
identical to any other sequence, its alignment will be delayed.  



<h3>Iterative realignment/Reset gaps between alignments</h3>

By default, if you align a set of sequences a second time (e.g. with changed
gap penalties), the gaps from the first alignment are discarded.  You can
set this from the menus so that older gaps will be kept between alignments,
This can sometimes give better alignments by keeping the gaps (do not reset
them) and doing the full multiple alignment a second time.  Sometimes, the
alignment will converge on a better solution; sometimes the new alignment will
be the same as the first.  There can be a strange side effect: you can get
columns of nothing but gaps introduced.  

<p>

Any gaps that are read in from the input file are always kept, regardless 
of the setting of this switch.  If you read in a full multiple alignment, the "reset
gaps" switch has no effect.  The old gaps will remain and if you carry out 
a multiple alignment, any new gaps will be added in.  If you wish to carry out 
a full new alignment of a set of sequences that are already aligned in a file
you must input the sequences without gaps.



<h3>Profile alignment</h3>

By profile alignment, we simply mean the alignment of old alignments/sequences.
In this context, a profile is just an existing alignment (or even a set of 
unaligned sequences; see below).  This allows you to
read in an old alignment (in any of the allowed input formats) and align
one or more new sequences to it.  From the profile alignment menu, you
are allowed to read in 2 profiles.  Either profile can be a full alignment
OR a single sequence.  In the simplest mode, you simply align the two profiles
to each other. This is useful if you want to gradually build up a full
multiple alignment.  

<p>

A second option is to align the sequences from the second profile, one at
a time to the first profile.  This is done, taking the underlying tree between
the sequences into account.  This is useful if you have a set of new sequences
(not aligned) and you wish to add them all to an older alignment.

<h2>Changes to the phylogentic tree calculations and some hints</h2>



<h3>Improved distance calculations for protein trees</h3>


The phylogenetic trees in Clustal W (the real trees that you calculate
AFTER alignment; not the guide trees used to decide the branching order
for multiple alignment) use the Neighbor-Joining method of Saitou and
Nei based on a matrix of "distances" between all sequences.  These distances
can be corrected for "multiple hits".  This is normal practice when accurate
trees are needed.  This correction stretches distances (especially large ones)
to try to correct for the fact that OBSERVED distances (mean number of 
differences per site) greatly underestimate the actual number that happened
during evolution.  

<p>

In Clustal V we used a simple formula to convert an observed distance to one
that is corrected for multiple hits.  The observed distance is the mean number
of differences per site in an alignment (ignoring sites with a gap) and is
therefore always between 0.0 (for ientical sequences) an 1.0 (no residues the
same at any site).  These distances can be multiplied by 100 to give percent
difference values.  100 minus percent difference gives percent identity.
The formula we use to correct for multiple hits is from Motoo Kimura
(Kimura, M. The neutral Theory of Molecular Evolution, Camb.Univ.Press, 1983,
page 75) and is:

<p>

K = -Ln(1 - D - (D.D)/5)  
<br>
where D is the observed distance and K is       
                              corrected distance.

<p>

This formula gives mean number of estimated substitutions per site and, in
contrast to D (the observed number), can be greater than 1 i.e. more than
one substitution per site, on average.  For example, if you observe 0.8
differences per site (80% difference; 20% identity), then the above formula
predicts that there have been 2.5 substitutions per site over the course 
of evolution since the 2 sequences diverged.  This can also be expressed in 
PAM units by multiplying by 100 (mean number of substitutions per 100 residues).
The PAM scale of evolution and its derivation/calculation comes from the
work of Margaret Dayhoff and co workers (the famous Dayhoff PAM series
of weight matrices also came from this work).  Dayhoff et al constructed
an elaborate model of protein evolution based on observed frequencies
of substitution between very closely related proteins.  Using this model,
they derived a table relating observed distances to predicted PAM distances.
Kimura's formula, above, is just a "curve fitting" approximation to this table.
It is very accurate in the range 0.75 > D > 0.0 but becomes increasingly
unaccurate at high D (>0.75) and fails completely at around D = 0.85.

<p>

To circumvent this problem, we calculated all the values for K corresponding
to D above 0.75 directly using the Dayhoff model and store these in an 
internal table, used by Clustal W.  This table is declared in the file dayhoff.h and
gives values of K for all D between 0.75 and 0.93 in intervals of 0.001 i.e.
for D = 0.750, 0.751, 0.752 ...... 0.929, 0.930.   For any observed D 
higher than 0.930, we arbitrarily set K to 10.0.  This sounds drastic but
with real sequences, distances of 0.93 (less than 7% identity) are rare.
If your data set includes sequences with this degree of divergence, you
will have great difficulty getting accurate trees by ANY method; the alignment
itself will be very difficult (to construct and to evaluate).

<p>

There are some important
things to note.  Firstly, this formula works well if your sequences are
of average amino acid composition and if the amino acids substitute according
to the original Dayhoff model.  In other cases, it may be misleading.  Secondly,
it is based only on observed percent distance i.e. it does not DIRECTLY
take conservative substitutions into account.  Thirdly, the error on the
estimated PAM distances may be VERY great for high distances; at very high
distance (e.g. over 85%) it may give largely arbitrary corrected distances.
In most cases, however, the correction is still worth using; the trees will
be more accurate and the branch lengths will be more realistic.  

<p>

A far more sophisticated distance correction based on a full Dayhoff
model which DOES take conservative substitutions and actual amino acid
composition into account, may be found in the PROTDIST program of the
PHYLIP package.  For serious tree makers, this program is highly recommended. 



<h3>TWO NOTES ON BOOTSTRAPPING...</h3>

When you use the BOOTSTRAP in Clustal W to estimate the reliability of parts
of a tree, many of the uncorrected distances may randomly exceed the arbitrary cut
off of 0.93 (sequences only 7% identical) if the sequences are distantly
related.  This will happen randomly i.e. even if none of the pairs of 
sequences are less than 7% identical, the bootstrap samples may contain pairs
of sequences that do exceed this cut off.
If this happens, you will be warned.  In practice, this can
happen with many data sets.  It is not a serious problem if it happens rarely.
If it does happen (you are warned when it happens and told how often the
problem occurs), you should consider removing the most distantly
related sequences and/or using the PHYLIP package instead.

<p>

A further problem arises in almost exactly the opposite situation: when
you bootstrap a data set which contains 3 or more sequences that are identical
or almost identical.  Here, the sets of identical sequences should be shown
as a multifurcation (several sequences joing at the same part of the tree).
Because the Neighbor-Joining method only gives strictly dichotomous trees
(never more than 2 sequences join at one time), this cannot be exactly 
represented.  In practice, this is NOT a problem as there will be some
internal branches of zero length seperating the sequences.  If you
display the tree with all branch lengths, you will still see a multifurcation.  
However, when you bootstrap
the tree, only the branching orders are stored and counted.  In the case
of multifurcations, the exact branching order is arbitrary but the program
will always get the same branching order, depending only on the input order
of the sequences.  In practice, this is only a problem in situations where
you have a set of sequences where all of them are VERY similar.  In this case,
you can find very high support for some groupings which will disappear if you
run the analysis with a different input order.  Again, the PHYLIP package
deals with this by offering a JUMBLE option to shuffle the input order
of your sequences between each bootstrap sample.  




<H2>
    References
</H2>

The main reference for ClustalW is Thompson et al below.

<ol>

<li>Thompson, J.D., Higgins, D.G. and Gibson, T.J. (1994)
"CLUSTAL W: improving the sensitivity of progressive multiple sequence
alignment through sequence weighting, positions-specific gap penalties
and weight matrix choice."
Nucleic Acids Research, 22:4673-4680.

<li>Feng, D.-F. and Doolittle, R.F. (1987). J. Mol. Evol. 25, 351-360.

<li>Needleman, S.B. and Wunsch, C.D. (1970). J. Mol. Biol. 48, 443-453.

<li>Dayhoff, M.O., Schwartz, R.M. and Orcutt, B.C. (1978) in Atlas of
Protein Sequence and Structure, vol. 5, suppl. 3 (Dayhoff, M.O., ed.),
pp 345-352, NBRF, Washington.

<li>Henikoff, S. and Henikoff, J.G. (1992). Proc. Natl. Acad. Sci. USA
89, 10915-10919.

<li>Lipman, D.J., Altschul, S.F. and Kececioglu,
J.D. (1989). Proc. Natl. Acad. Sci. USA 86, 4412-4415.

<li>Barton, G.J. and Sternberg, M.J.E. (1987). J. Mol. Biol. 198, 327-337.

<li>Gotoh, O. (1993). CABIOS 9, 361-370.

<li>Altschul, S.F. (1989). J. Theor. Biol. 138, 297-309.

<li>Lukashin, A.V., Engelbrecht, J. and Brunak, S. (1992). Nucl. Acids
Res. 20, 2511-2516.

<li>Lawrence, C.E., Altschul, S.F., Boguski, M.S., Liu, J.S., Neuwald,
A.F. and Wooton, J.C. (1993). Science, 262, 208-214.

<li>Vingron, M. and Waterman, M.S. (1993). J. Mol. Biol. 234, 1-12.

<li>Pascarella, S. and Argos, P. (1992). J. Mol. Biol. 224, 461-471.

<li>Collins, J.F. and Coulson, A.F.W. (1987). In Nucleic acid and
protein sequence analysis a practical approach, Bishop, M.J. and
Rawlings, C.J. ed., chapter 13, pp. 323-358.

<li>Vingron, M. and Sibbald, P.R. (1993). Proc. Natl. Acad. Sci. USA,
90, 8777-8781.

<li>Thompson, J.D., Higgins, D.G. and Gibson, T.J. (1994). CABIOS, 10, 19-29.

<li>Lthy, R., Xenarios, I. and Bucher, P. (1994). Protein Science, 3, 139-146.

<li>Higgins, D.G. and Sharp, P.M. (1988). Gene, 73, 237-244.

<li>Higgins, D.G. and Sharp, P.M. (1989). CABIOS, 5, 151-153.

<li>Higgins, D.G., Bleasby, A.J. and Fuchs, R. (1992). CABIOS, 8, 189-191.

<li>Sneath, P.H.A. and Sokal, R.R. (1973). Numerical Taxonomy,
W.H. Freeman, San Francisco.

<li>Saitou, N. and Nei, M. (1987). Mol. Biol. Evol. 4, 406-425.

<li>Wilbur, W.J. and Lipman, D.J. (1983). Proc. Natl. Acad. Sci. USA,
80, 726-730.

<li>Musacchio, A., Gibson, T., Lehto, V.-P. and Saraste,
M. (1992). FEBS Lett. 307, 55-61.

<li>Musacchio, A., Noble, M., Pauptit, R., Wierenga, R. and Saraste,
M. (1992). Nature, 359, 851-855.

<li>Bashford, D., Chothia, C. and Lesk,
A.M. (1987). J. Mol. Biol. 196, 199-216.

<li>Myers, E.W. and Miller, W. (1988). CABIOS, 4, 11-17.

<li>Thompson, J.D. (1994). CABIOS, (Submitted).

<li>Smith, T.F., Waterman, M.S. and Fitch,
W.M. (1981). J. Mol. Evol. 18, 38-46.

<li>Pearson, W.R. and Lipman,
D.J. (1988). Proc. Natl. Acad. Sci. USA. 85, 2444-2448.

<li>Devereux, J., Haeberli, P. and Smithies, O. (1984). Nucleic Acids
Res. 12, 387-395.

<li>Felsenstein, J. (1989). Cladistics 5, 164-166.

<li>Kimura, M. (1980). J. Mol. Evol. 16, 111-120.

<li>Kimura, M. (1983). The Neutral Theory of Molecular Evolution.
Cambridge University Press, Cambridge.

<li>Felsenstein, J. (1985). Evolution 39, 783-791.

<li>Smith, R.F. and Smith, T.F. (1992) Protein Engineering 5, 35-41.

<li>Krogh, A., Brown, M., Mian, S., Sjlander, K. and Haussler,
D. (1994) J. Mol. Biol. 235-1501-1531.

<li>Jones, D.T., Taylor, W.R. and Thornton, J.M.  (1994). FEBS
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<li>Bairoch, A. and Bckmann, B. (1992) Nucleic Acids Res., 20, 2019-2022.

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<li>Kabsch, W. and Sander, C. (1983) Biopolymers, 22, 2577-2637.

</ol>

<H2>
    Warnings
</H2>

None.

<H2>
    Diagnostic Error Messages
</H2>

"cannot find program 'clustalw'" - means that the ClustalW program has
not been set up on your site or is not in your environment (i.e.  is
not on your path). The solutions are to (1) install clustalw in the
path so that emma can find it with the command "clustalw", or (2)
define a variable (an environment variable or in emboss.defaults or
your .embossrc file) called EMBOSS_CLUSTALW containing the command
(program name or full path) to run clustalw if you have it elsewhere
on your system.

<H2>
    Exit status
</H2>

It exits with status 0 unless an error is reported

<H2>
    Known bugs
</H2>

None. 


<h2><a name="See also">See also</a></h2>
<table border cellpadding=4 bgcolor="#FFFFF0">
<tr><th>Program name</th>
<th>Description</th></tr>
<tr>
<td><a href="edialign.html">edialign</a></td>
<td>Local multiple alignment of sequences</td>
</tr>

<tr>
<td><a href="infoalign.html">infoalign</a></td>
<td>Display basic information about a multiple sequence alignment</td>
</tr>

<tr>
<td><a href="plotcon.html">plotcon</a></td>
<td>Plot conservation of a sequence alignment</td>
</tr>

<tr>
<td><a href="prettyplot.html">prettyplot</a></td>
<td>Draw a sequence alignment with pretty formatting</td>
</tr>

<tr>
<td><a href="showalign.html">showalign</a></td>
<td>Display a multiple sequence alignment in pretty format</td>
</tr>

<tr>
<td><a href="tranalign.html">tranalign</a></td>
<td>Generate an alignment of nucleic coding regions from aligned proteins</td>
</tr>

</table>

<H2>
    Author(s)
</H2>


Mark Faller formerly at:
<br>
HGMP-RC, Genome Campus, Hinxton, Cambridge CB10 1SB, UK

<p>
Please report all bugs to the EMBOSS bug team (emboss-bug&nbsp;&copy;&nbsp;emboss.open-bio.org) not to the original author.


<H2>
    History
</H2>


Completed  18 February 1999

<H2>
    Target users
</H2>
This program is intended to be used by everyone and everything, from naive users to embedded scripts.

<H2>
    Comments
</H2>
None
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