plotcon

 

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Function

Plot conservation of a sequence alignment

Description

plotcon reads a sequence alignment and draws a plot of the sequence conservation within windows over the alignment.

Algorithm

Sequence conservation is calculated for windows of a specified length over the alignment. Within a window, the similarity of any one position is taken to be the average of all the possible pairwise substitution scores of the bases or residues at that position. The pairwise substitution scores are taken from the specified similarity matrix. The average of the position similarities within the window is plotted.

The average similarity is calculated by:


Av. Sim. =       sum( Mij*wi + Mji*wj  )
                      -------------------
                  (Nseq*Wsize)*((Nseq-1)*Wsize)

sum - over column*window size
w - sequence weighting
M - matrix comparison table
i,j - with respect to residue i or j
Nseq - number of sequences in the alignment
Wsize - window size

Usage

Here is a sample session with plotcon


% plotcon -sformat msf globins.msf -graph cps 
Plot conservation of a sequence alignment
Window size [4]: 

Created plotcon.ps

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

Command line arguments

Plot conservation of a sequence alignment
Version: EMBOSS:6.5.0.0

   Standard (Mandatory) qualifiers:
  [-sequences]         seqset     File containing a sequence alignment
   -winsize            integer    [4] Number of columns to average alignment
                                  quality over. The larger this value is, the
                                  smoother the plot will be. (Any integer
                                  value)
   -graph              xygraph    [$EMBOSS_GRAPHICS value, or x11] Graph type
                                  (ps, hpgl, hp7470, hp7580, meta, cps, x11,
                                  tek, tekt, none, data, xterm, png, gif, pdf,
                                  svg)

   Additional (Optional) qualifiers:
   -scorefile          matrix     [EBLOSUM62 for protein, EDNAFULL for DNA]
                                  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: (none)
   Associated qualifiers:

   "-sequences" 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
   -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

   "-graph" associated qualifiers
   -gprompt            boolean    Graph prompting
   -gdesc              string     Graph description
   -gtitle             string     Graph title
   -gsubtitle          string     Graph subtitle
   -gxtitle            string     Graph x axis title
   -gytitle            string     Graph y axis title
   -goutfile           string     Output file for non interactive displays
   -gdirectory         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

Qualifier Type Description Allowed values Default
Standard (Mandatory) qualifiers
[-sequences]
(Parameter 1)
seqset File containing a sequence alignment Readable set of sequences Required
-winsize integer Number of columns to average alignment quality over. The larger this value is, the smoother the plot will be. Any integer value 4
-graph xygraph Graph type EMBOSS has a list of known devices, including ps, hpgl, hp7470, hp7580, meta, cps, x11, tek, tekt, none, data, xterm, png, gif, pdf, svg EMBOSS_GRAPHICS value, or x11
Additional (Optional) qualifiers
-scorefile matrix 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
(none)
Associated qualifiers
"-sequences" associated seqset qualifiers
-sbegin1
-sbegin_sequences
integer Start of each sequence to be used Any integer value 0
-send1
-send_sequences
integer End of each sequence to be used Any integer value 0
-sreverse1
-sreverse_sequences
boolean Reverse (if DNA) Boolean value Yes/No N
-sask1
-sask_sequences
boolean Ask for begin/end/reverse Boolean value Yes/No N
-snucleotide1
-snucleotide_sequences
boolean Sequence is nucleotide Boolean value Yes/No N
-sprotein1
-sprotein_sequences
boolean Sequence is protein Boolean value Yes/No N
-slower1
-slower_sequences
boolean Make lower case Boolean value Yes/No N
-supper1
-supper_sequences
boolean Make upper case Boolean value Yes/No N
-scircular1
-scircular_sequences
boolean Sequence is circular Boolean value Yes/No N
-sformat1
-sformat_sequences
string Input sequence format Any string  
-iquery1
-iquery_sequences
string Input query fields or ID list Any string  
-ioffset1
-ioffset_sequences
integer Input start position offset Any integer value 0
-sdbname1
-sdbname_sequences
string Database name Any string  
-sid1
-sid_sequences
string Entryname Any string  
-ufo1
-ufo_sequences
string UFO features Any string  
-fformat1
-fformat_sequences
string Features format Any string  
-fopenfile1
-fopenfile_sequences
string Features file name Any string  
"-graph" associated xygraph qualifiers
-gprompt boolean Graph prompting Boolean value Yes/No N
-gdesc string Graph description Any string  
-gtitle string Graph title Any string  
-gsubtitle string Graph subtitle Any string  
-gxtitle string Graph x axis title Any string Relative Residue Position
-gytitle string Graph y axis title Any string  
-goutfile string Output file for non interactive displays Any string  
-gdirectory string Output directory Any string  
General qualifiers
-auto boolean Turn off prompts Boolean value Yes/No N
-stdout boolean Write first file to standard output Boolean value Yes/No N
-filter boolean Read first file from standard input, write first file to standard output Boolean value Yes/No N
-options boolean Prompt for standard and additional values Boolean value Yes/No N
-debug boolean Write debug output to program.dbg Boolean value Yes/No N
-verbose boolean Report some/full command line options Boolean value Yes/No Y
-help boolean Report command line options and exit. More information on associated and general qualifiers can be found with -help -verbose Boolean value Yes/No N
-warning boolean Report warnings Boolean value Yes/No Y
-error boolean Report errors Boolean value Yes/No Y
-fatal boolean Report fatal errors Boolean value Yes/No Y
-die boolean Report dying program messages Boolean value Yes/No Y
-version boolean Report version number and exit Boolean value Yes/No N

Input file format

plotcon reads a set of gapped, aligned sequences.

Input files for usage example

File: globins.msf

!!AA_MULTIPLE_ALIGNMENT 1.0

  ../data/globins.msf MSF:  164 Type: P 25/06/01 CompCheck: 4278 ..

  Name: HBB_HUMAN Len: 164  Check: 6914 Weight: 0.61
  Name: HBB_HORSE Len: 164  Check: 6007 Weight: 0.65
  Name: HBA_HUMAN Len: 164  Check: 3921 Weight: 0.65
  Name: HBA_HORSE Len: 164  Check: 4770 Weight: 0.83
  Name: MYG_PHYCA Len: 164  Check: 7930 Weight: 1.00
  Name: GLB5_PETMA Len: 164  Check: 1857 Weight: 0.91
  Name: LGB2_LUPLU Len: 164  Check: 2879 Weight: 0.43

//

           1                                               50
HBB_HUMAN  ~~~~~~~~VHLTPEEKSAVTALWGKVN.VDEVGGEALGR.LLVVYPWTQR
HBB_HORSE  ~~~~~~~~VQLSGEEKAAVLALWDKVN.EEEVGGEALGR.LLVVYPWTQR
HBA_HUMAN  ~~~~~~~~~~~~~~VLSPADKTNVKAA.WGKVGAHAGEYGAEALERMFLS
HBA_HORSE  ~~~~~~~~~~~~~~VLSAADKTNVKAA.WSKVGGHAGEYGAEALERMFLG
MYG_PHYCA  ~~~~~~~VLSEGEWQLVLHVWAKVEAD.VAGHGQDILIR.LFKSHPETLE
GLB5_PETMA PIVDTGSVAPLSAAEKTKIRSAWAPVYSTYETSGVDILVKFFTSTPAAQE
LGB2_LUPLU ~~~~~~~~GALTESQAALVKSSWEEFNANIPKHTHRFFILVLEIAPAAKD

           51                                             100
HBB_HUMAN  FFESFGDLSTPDAVMGNPKVKAHGKKVLGAFSDGLAHLDNLKGTFATLSE
HBB_HORSE  FFDSFGDLSNPGAVMGNPKVKAHGKKVLHSFGEGVHHLDNLKGTFAALSE
HBA_HUMAN  FPTTKTYFPHFDLSHGSAQVKGHGKKVADALTNAVAHVDDMPNALSALSD
HBA_HORSE  FPTTKTYFPHFDLSHGSAQVKAHGKKVGDALTLAVGHLDDLPGALSNLSD
MYG_PHYCA  KFDRFKHLKTEAEMKASEDLKKHGVTVLTALGAILKKKGHHEAELKPLAQ
GLB5_PETMA FFPKFKGLTTADQLKKSADVRWHAERIINAVNDAVASMDDTEKMSMKLRD
LGB2_LUPLU LFSFLKGTSEVPQNNPELQAHAGKVFKLVYEAAIQLQVTGVVVTDATLKN

           101                                            150
HBB_HUMAN  LHCDKLH..VDPENFRLLGNVLVCVLAHHFGKEFTPPVQAAYQKVVAGVA
HBB_HORSE  LHCDKLH..VDPENFRLLGNVLVVVLARHFGKDFTPELQASYQKVVAGVA
HBA_HUMAN  LHAHKLR..VDPVNFKLLSHCLLVTLAAHLPAEFTPAVHASLDKFLASVS
HBA_HORSE  LHAHKLR..VDPVNFKLLSHCLLSTLAVHLPNDFTPAVHASLDKFLSSVS
MYG_PHYCA  SHATKHK..IPIKYLEFISEAIIHVLHSRHPGDFGADAQGAMNKALELFR
GLB5_PETMA LSGKHAK..SFQVDPQYFKVLAAVIADTVAAGDAGFEKLMSMICILLRSA
LGB2_LUPLU LGSVHVSKGVADAHFPVVKEAILKTIKEVVGAKWSEELNSAWTIAYDELA

           151        164
HBB_HUMAN  NALAHKYH~~~~~~
HBB_HORSE  NALAHKYH~~~~~~
HBA_HUMAN  TVLTSKYR~~~~~~
HBA_HORSE  TVLTSKYR~~~~~~
MYG_PHYCA  KDIAAKYKELGYQG
GLB5_PETMA Y~~~~~~~~~~~~~
LGB2_LUPLU IVIKKEMNDAA~~~

Output file format

A graph of the quality of the alignment is dispalyed on the specifed graphics device.

Output files for usage example

Graphics File: plotcon.ps

[plotcon results]

Data files

It reads in the specified similarity matrix.

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:

Notes

The program is useful for visualising the quality of alignment along its length. This can give a qualitative insight into where there are regions of conservation in a group of aligned sequences.

Note that you should only compare the results of two runs of plotcon if you use the same window size in each. This is because the 'similarity score' units that are output are very sensitive to the size of the window. A large window (e.g. 100) gives a nice, smooth curve, and very low 'similarity score' units, whereas a small window (e.g. 4) gives a very spikey, noisy plot with 'similarity score' units of a round 1.00

References

None.

Warnings

plotcon does not distinguish between aligned and unaligned sets of sequences. If the input set of sequences is unaligned, the output will in most cases lack much biological meaning.

Diagnostic Error Messages

None.

Exit status

It always exits with status 0.

Known bugs

None.

See also

Program name Description
edialign Local multiple alignment of sequences
emma Multiple sequence alignment (ClustalW wrapper)
infoalign Display basic information about a multiple sequence alignment
prettyplot Draw a sequence alignment with pretty formatting
showalign Display a multiple sequence alignment in pretty format
tranalign Generate an alignment of nucleic coding regions from aligned proteins

Author(s)

Tim Carver formerly at:
MRC Rosalind Franklin Centre for Genomics Research Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SB, UK

Please report all bugs to the EMBOSS bug team (emboss-bug © emboss.open-bio.org) not to the original author.

History

Written (Sept 2000) - Tim Carver.

Target users

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

Comments

None