EMBOSS: plotcon

| plotcon

## 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

       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,
                                      tekt, tek, none, data, xterm, png, gif)

       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
       -sformat1           string     Input sequence format
       -sdbname1           string     Database name
       -sid1               string     Entryname
       -ufo1               string     UFO features
       -fformat1           string     Features format
       -fopenfile1         string     Features file name

       "-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. 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

Standard (Mandatory) qualifiers | Allowed values | Default
--- | --- | ---
[-sequences] (Parameter 1) | File containing a sequence alignment | Readable set of sequences | Required
-winsize | Number of columns to average alignment quality over. The larger this value is, the smoother the plot will be. | Any integer value | 4
-graph | Graph type | EMBOSS has a list of known devices, including ps, hpgl, hp7470, hp7580, meta, cps, x11, tekt, tek, none, data, xterm, png, gif | EMBOSS_GRAPHICS value, or x11
Additional (Optional) qualifiers | Allowed values | Default
-scorefile | This is the scoring matrix file used when comparing sequences. By default it is the file 'EBLOSUM62' (for proteins) or the file 'EDNAFULL' (for nucleic sequences). These files are found in the 'data' directory of the EMBOSS installation. | Comparison matrix file in EMBOSS data path | EBLOSUM62 for protein EDNAFULL for DNA
Advanced (Unprompted) qualifiers | Allowed values | Default
(none)

## 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

## 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:

- . (your current directory)
- .embossdata (under your current directory)
- ~/ (your home directory)
- ~/.embossdata

## 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 aligment of nucleic coding regions from aligned proteins

## Author(s)

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

## 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