/ 
bioperl-1.2.2
/ Bio::Tools::Lucy

NAME

Bio::Tools::Lucy - Object for analyzing the output from Lucy, a vector and quality trimming program from TIGR

SYNOPSIS

# Create the Lucy object from an existing Lucy output file 
@params = ('seqfile' => 'lucy.seq', 'lucy_verbose' => 1);
$lucyObj = Bio::Tools::Lucy->new(@params);

# Get names of all sequences
$names = $lucyObj->get_sequence_names();

#  Print seq and qual values for sequences >400 bp in order to run CAP3
foreach $name (@$names) {
    next unless $lucyObj->length_clear($name) > 400;
    print SEQ ">$name\n", $lucyObj->sequence($name), "\n";
    print QUAL ">$name\n", $lucyObj->quality($name), "\n";
}

# Get an array of Bio::PrimarySeq objects
@seqObjs = $lucyObj->get_Seq_Objs();

DESCRIPTION

Bio::Tools::Lucy.pm provides methods for analyzing the sequence and quality values generated by Lucy program from TIGR.

Lucy will identify vector, poly-A/T tails, and poor quality regions in a sequence. (www.genomics.purdue.edu/gcg/other/lucy.pdf)

The input to Lucy can be the Phred sequence and quality files generated from running Phred on a set of chromatograms.

Lucy can be obtained (free of charge to academic users) from www.tigr.org/softlab

There are a few methods that will only be available if you make some minor changes to the source for Lucy and then recompile. The changes are in the 'lucy.c' file and there is a diff between the original and the modified file in the Appendix

Please contact the author of this module if you have any problems making these modifications.

You do not have to make these modifications to use this module.

Creating a Lucy object

  @params = ('seqfile' => 'lucy.seq', 'adv_stderr' => 1, 
	     'fwd_desig' => '_F', 'rev_desig' => '_R');
  $lucyObj = Bio::Tools::Lucy->new(@params);

Using a Lucy object

  You should get an array with the sequence names in order to use
  accessor methods.  Note: The Lucy binary program will fail unless
  the sequence names provided as input are unique.

  $names_ref = $lucyObj->get_sequence_names();

  This code snippet will produce a Fasta format file with sequence
  lengths and %GC in the description line.

  foreach $name (@$names) {
      print FILE ">$name\t",
		 $lucyObj->length_clear($name), "\t",
		 $lucyObj->per_GC($name), "\n",
		 $lucyObj->sequence($name), "\n";  
  }


  Print seq and qual values for sequences >400 bp in order to assemble
  them with CAP3 (or other assembler).

  foreach $name (@$names) {
      next unless $lucyObj->length_clear($name) > 400;
      print SEQ ">$name\n", $lucyObj->sequence($name), "\n";
      print QUAL ">$name\n", $lucyObj->quality($name), "\n";
  }

  Get all the sequences as Bio::PrimarySeq objects (eg., for use with
  Bio::Tools::Blast to perform BLAST).

  @seqObjs = $lucyObj->get_Seq_Objs();

  Or use only those sequences that are full length and have a Poly-A
  tail.

  foreach $name (@$names) {
      next unless ($lucyObj->full_length($name) and $lucy->polyA($name));
      push @seqObjs, $lucyObj->get_Seq_Obj($name);
  }


  Get the names of those sequences that were rejected by Lucy.

  $rejects_ref = $lucyObj->get_rejects();

  Print the names of the rejects and 1 letter code for reason they
  were rejected.

  foreach $key (sort keys %$rejects_ref) {
      print "$key:  ", $rejects_ref->{$key};
  }

  There is a lot of other information available about the sequences
  analyzed by Lucy (see APPENDIX).  This module can be used with the
  DBI module to store this sequence information in a database.

FEEDBACK

Mailing Lists

User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments and suggestions preferably to one of the Bioperl mailing lists. Your participation is much appreciated.

bioperl-l@bioperl.org             - General discussion
http://bio.perl.org/MailList.html - About the mailing lists

Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track the bugs and their resolution. Bug reports can be submitted via email or the web:

bioperl-bugs@bio.perl.org
http://bugzilla.bioperl.org/

AUTHOR

Andrew G. Walsh paeruginosa@hotmail.com

APPENDIX

Methods available to Lucy objects are described below. Please note that any method beginning with an underscore is considered internal and should not be called directly.

new

 Title	 :  new
 Usage	 :  $lucyObj = Bio::Tools::Lucy->new(seqfile => lucy.seq, rev_desig => '_R', 
	    fwd_desig => '_F')
 Function:  creates a Lucy object from Lucy analysis files
 Returns :  reference to Bio::Tools::Lucy object
 Args	 :  seqfile	Fasta sequence file generated by Lucy
	    qualfile	Quality values file generated by Lucy
	    infofile	Info file created when Lucy is run with -debug 'infofile' option
	    stderrfile	Standard error captured from Lucy when Lucy is run 
			with -info option and STDERR is directed to stderrfile 
			(ie. lucy ... 2> stderrfile).
			Info in this file will include sequences dropped for low 
			quality. If you've modified Lucy source (see adv_stderr below), 
			it will also include info on which sequences were dropped because 
			they were vector, too short, had no insert, and whether a poly-A 
			tail was found (if Lucy was run with -cdna option).
	    lucy_verbose verbosity level (0-1).  
	    fwd_desig	The string used to determine whether sequence is a forward read.  
			The parser will assume that this match will occus at the 
			end of the sequence name string.
	    rev_desig	As above, for reverse reads. 
 	    adv_stderr	Can be set to a true value (1).  Will only work if you have modified 
			the Lucy source code as outlined in DESCRIPTION and capture 
			the standard error from Lucy.

If you don't provide filenames for qualfile, infofile or stderrfile, the module will assume that .qual, .info, and .stderr are the file extensions and search in the same directory as the .seq file for these files.

For example, if you create a Lucy object with $lucyObj = Bio::Tools::Lucy->new(seqfile =>lucy.seq), the module will find lucy.qual, lucy.info and lucy.stderr.

You can omit any or all of the quality, info or stderr files, but you will not be able to use all of the object methods (see method documentation below).

_parse

Title	 :  _parse
Usage	 :  n/a (internal function)
Function:  called by new() to parse Lucy output files
Returns :  nothing
Args	 :  none

get_Seq_Objs

 Title   :  get_Seq_Objs
 Usage   :  $lucyObj->get_Seq_Objs()
 Function:  returns an array of references to Bio::PrimarySeq objects 
	    where -id = 'sequence name' and -seq = 'sequence'

 Returns :  array of Bio::PrimarySeq objects
 Args	 :  none

get_Seq_Obj

 Title   :  get_Seq_Obj
 Usage   :  $lucyObj->get_Seq_Obj($seqname)
 Function:  returns reference to a Bio::PrimarySeq object where -id = 'sequence name'
	    and -seq = 'sequence'
 Returns :  reference to Bio::PrimarySeq object
 Args	 :  name of a sequence

get_sequence_names

 Title   :  get_sequence_names
 Usage   :  $lucyObj->get_sequence_names
 Function:  returns reference to an array of names of the sequences analyzed by Lucy.
	    These names are required for most of the accessor methods.  
	    Note: The Lucy binary will fail unless sequence names are unique.
 Returns :  array reference
 Args	 :  none

sequence

Title   :  sequence
Usage   :  $lucyObj->sequence($seqname)
Function:  returns the DNA sequence of one of the sequences analyzed by Lucy.
Returns :  string
Args	 :  name of a sequence

quality

 Title   :  quality
 Usage   :  $lucyObj->quality($seqname)
 Function:  returns the quality values of one of the sequences analyzed by Lucy.
	    This method depends on the user having provided a quality file.
 Returns :  string
 Args    :  name of a sequence

avg_quality

Title   :  avg_quality
Usage   :  $lucyObj->avg_quality($seqname)
Function:  returns the average quality value for one of the sequences analyzed by Lucy.
Returns :  float
Args    :  name of a sequence

direction

 Title   :  direction
 Usage   :  $lucyObj->direction($seqname)
 Function:  returns the direction for one of the sequences analyzed by Lucy
	    providing that 'fwd_desig' or 'rev_desig' were set when the
 	    Lucy object was created.
	    Strings returned are: 'F' for forward, 'R' for reverse.  
 Returns :  string 
 Args    :  name of a sequence

length_raw

 Title   :  length_raw
 Usage   :  $lucyObj->length_raw($seqname)
 Function:  returns the length of a DNA sequence prior to quality/ vector 
	    trimming by Lucy.
 Returns :  integer
 Args    :  name of a sequence

length_clear

Title   :  length_clear
Usage   :  $lucyObj->length_clear($seqname)
Function:  returns the length of a DNA sequence following quality/ vector   
           trimming by Lucy.
Returns :  integer
Args    :  name of a sequence

start_clear

 Title   :  start_clear
 Usage   :  $lucyObj->start_clear($seqname)
 Function:  returns the beginning position of good quality, vector free DNA sequence 
	    determined by Lucy.
 Returns :  integer
 Args    :  name of a sequence

end_clear

Title   :  end_clear
Usage   :  $lucyObj->end_clear($seqname)
Function:  returns the ending position of good quality, vector free DNA sequence
           determined by Lucy.
Returns :  integer
Args    :  name of a sequence

per_GC

Title   :  per_GC
Usage   :  $lucyObj->per_GC($seqname)
Function:  returns the percente of the good quality, vector free DNA sequence
           determined by Lucy.
Returns :  float
Args    :  name of a sequence

full_length

Title   :  full_length
Usage   :  $lucyObj->full_length($seqname)
Function:  returns the truth value for whether or not the sequence read was
           full length (ie. vector present on both ends of read).  This method
           depends on the user having provided the 'info' file (Lucy must be
           run with the -debug 'info_filename' option to get this file).
Returns :  boolean 
Args    :  name of a sequence

polyA

Title   :  polyA
Usage   :  $lucyObj->polyA($seqname)
Function:  returns the truth value for whether or not a poly-A tail was detected
           and clipped by Lucy.  This method depends on the user having modified
           the source for Lucy as outlined in DESCRIPTION and invoking Lucy with
           the -cdna option and saving the standard error.
           Note, the final sequence will not show the poly-A/T region.
Returns :  boolean
Args    :  name of a sequence

get_rejects

 Title   :  get_rejects
 Usage   :  $lucyObj->get_rejects()
 Function:  returns a hash containing names of rejects and a 1 letter code for the 
 	    reason Lucy rejected the sequence.
	    Q- rejected because of low quality values
	    S- sequence was short
	    V- sequence was vector 
	    E- sequence was empty
	    P- poly-A/T trimming caused sequence to be too short
	    In order to get the rejects, you must provide a file with the standard
	    error from Lucy.  You will only get the quality category rejects unless
	    you have modified the source and recompiled Lucy as outlined in DESCRIPTION.
 Returns :  hash reference
 Args    :  none

Diff for Lucy source code

352a353,354
>       /* AGW added next line */
>       fprintf(stderr, "Empty: %s\n", seqs[i].name);
639a642,643
> 	    /* AGW added next line */
> 	    fprintf(stderr, "Short/ no insert: %s\n", seqs[i].name);
678c682,686
< 	if (left) seqs[i].left+=left;
---
> 	if (left) {
> 	  seqs[i].left+=left;
> 	  /*  AGW added next line */
> 	  fprintf(stderr, "%s has PolyA (left).\n", seqs[i].name);
> 	}
681c689,693
< 	if (right) seqs[i].right-=right;
---
> 	if (right) {
> 	  seqs[i].right-=right;
> 	  /* AGW added next line */
> 	  fprintf(stderr, "%s has PolyA (right).\n", seqs[i].name);
> 	}
682a695,696
> 	  /* AGW added next line */
> 	  fprintf(stderr, "Dropped PolyA: %s\n", seqs[i].name);	
734a749,750
> 	  /* AGW added next line */
> 	  fprintf(stderr, "Vector: %s\n", seqs[i].name);