| ## EMBOSS: equicktandem

# Program equicktandem

## Function

Finds tandem repeats

## Description

equicktandem scans a sequence for potential tandem repeats up to a specified size. The results can be used to run etandem on the candidate repeat lengths to identify genuine tandem repeats.

equicktandem is a simple program that looks for segments in which each base tends to match the base 'repeatsize' back, i.e. with an autocorrelation peak at 'repeatsize'. This can allow drift in the repeating sequence, i.e. it does not look for a consensus sequence for the whole repeat block (that is what etandem does). But it is much quicker than etandem. It does not account for gaps.

The score is +1 for a match to the corresponding base 'repeatsize' back and -1 for a mismatch.

## Usage

Here is a sample session with equicktandem. The input sequence is the human herpesvirus tandem repeat.

    % equicktandem
    Input sequence: embl:hhtetra
    Output file [hhtetra.qtan]:
    Maximum repeat size [600]:
    Threshold score [20]:

## Command line arguments

       Mandatory qualifiers:
      [-sequence]          sequence   Sequence USA
       -maxrepeat          integer    Maximum repeat size
       -threshold          integer    Threshold score
      [-outfile]           report     (no help text) report value

       Optional qualifiers: (none)
       Advanced qualifiers:
       -origfile           outfile    Output file name

       General qualifiers:
      -help                bool       report command line options. More
                                      information on associated and general
                                      qualifiers can be found with -help -verbose

Mandatory qualifiers | Allowed values | Default
--- | --- | ---
[-sequence] (Parameter 1) | Sequence USA | Readable sequence | Required
-maxrepeat | Maximum repeat size | Any integer value | 600
-threshold | Threshold score | Any integer value | 20
[-outfile] (Parameter 2) | (no help text) report value | Report file |
Optional qualifiers | Allowed values | Default
(none)
Advanced qualifiers | Allowed values | Default
-origfile | Output file name | Output file | <sequence>.equicktandem

## Input file format

The input for equicktandem is a nucleotide sequence

## Output file format

The output is a standard EMBOSS report file.

The results can be output in one of several styles by using the command-line qualifier -rformat xxx, where 'xxx' is replaced by the name of the required format. The available format names are: embl, genbank, gff, pir, swiss, trace, listfile, dbmotif, diffseq, excel, feattable, motif, regions, seqtable, simple, srs, table, tagseq

See: http://www.uk.embnet.org/Software/EMBOSS/Themes/ReportFormats.html for further information on report formats.

By default equicktandem writes a 'table' report file.

The output from the above example is:

    ########################################
    # Program: equicktandem
    # Rundate: Thu Apr 11 13:28:55 2002
    # Report_file: stdout
    ########################################

    #=======================================
    #
    # Sequence: HHTETRA     from: 1   to: 1272
    # HitCount: 1
    #
    # Threshold: 20
    # Maxrepeat: 600
    #
    #=======================================

      Start     End   Score   Size  Count
        191     935     339      6    124

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

## Data files

None.

## Notes

None.

## References

None.

## Warnings

None.

## Diagnostic Error Messages

None.

## Exit status

It always exits with a status of 0.

## Known bugs

None.

## See also

Program name | Description
--- | ---
einverted | Finds DNA inverted repeats
etandem | Looks for tandem repeats in a nucleotide sequence
palindrome | Looks for inverted repeats in a nucleotide sequence

equicktandem identifies regions wich are likely to contain tanden repeats. tandem should then be run on those regions to confirm them and to get an accurate specification of the repeats. tandem runs slowly.

## Author(s)

This program was originally written by Richard Durbin at the Sanger Centre.

This application was modified for inclusion in EMBOSS by Peter Rice (pmr@sanger.ac.uk) Informatics Division, The Sanger Centre, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.

## History

Completed 25 May 1999

## Target users

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

## Comments