Summary

Bio::AlignIO::bl2seq - bl2seq sequence input/output stream

Package variables

Included modules

Inherit

Bio::AlignIO

Synopsis

Do not use this module directly. Use it via the Bio::AlignIO class, as in:

    use Bio::AlignIO;

    $in  = Bio::AlignIO->new(-file => "inputfilename" , '-format' => 'bl2seq');
    $aln = $in->next_aln();

Description

This object can create Bio::SimpleAlign sequence alignment objects (of
2 sequences) from bl2seq BLAST reports.
A nice feature of this module is that- in combination with
StandAloneBlast.pm or remote blasting - it can be used to align 2
sequences and make a SimpleAlign object from them which can then be
manipulated using any SimpleAlign.pm methods, eg:

   #Get 2 sequences
   $str = Bio::SeqIO->new(-file=>'t/amino.fa' , '-format' => 'Fasta', );
   my $seq3 = $str->next_seq();
   my $seq4 = $str->next_seq();

   # Run bl2seq on them
   $factory = Bio::Tools::StandAloneBlast->new('program' => 'blastp', 
					       'outfile' => 'bl2seq.out');
   my $bl2seq_report = $factory->bl2seq($seq3, $seq4);

   # Use AlignIO.pm to create a SimpleAlign object from the bl2seq report
   $str = Bio::AlignIO->new(-file=> 'bl2seq.out','-format' => 'bl2seq');
   $aln = $str->next_aln();

Methods

Methods description

 Title   : next_aln
 Usage   : $aln = $stream->next_aln()
 Function: returns the next alignment in the stream.
 Returns : Bio::Align::AlignI object - returns 0 on end of file
	    or on error
 Args    : NONE

 Title   : write_aln
 Usage   : $stream->write_aln(@aln)
 Function: writes the $aln object into the stream in bl2seq format
 Returns : 1 for success and 0 for error
 Args    : Bio::Align::AlignI object

Methods code

sub next_aln {

    my $self = shift;
    my ($start,$end,$name,$seqname,$seq,$seqchar);
    my $aln =  Bio::SimpleAlign->new(-source => 'bl2seq');
    $self->{'bl2seqobj'} =
    	$self->{'bl2seqobj'} || Bio::Tools::BPbl2seq->new(-fh => $self->_fh);
    my $bl2seqobj = $self->{'bl2seqobj'};
    my $hsp =   $bl2seqobj->next_feature;
    $seqchar = $hsp->querySeq;
    $start = $hsp->query->start;
    $end = $hsp->query->end;
    $seqname = 'Query-sequence';    # Query name not present in bl2seq report

#    unless ($seqchar && $start && $end  && $seqname) {return 0} ;	
    unless ($seqchar && $start && $end ) {return 0} ;	

    $seq = new Bio::LocatableSeq('-seq'=>$seqchar,
				 '-id'=>$seqname,
				 '-start'=>$start,
				 '-end'=>$end,
				 );

    $aln->add_seq($seq);

    $seqchar = $hsp->sbjctSeq;
    $start = $hsp->hit->start;
    $end = $hsp->hit->end;
    $seqname = $bl2seqobj->sbjctName;

    unless ($seqchar && $start && $end  && $seqname) {return 0} ;	

    $seq = new Bio::LocatableSeq('-seq'=>$seqchar,
				 '-id'=>$seqname,
				 '-start'=>$start,
				 '-end'=>$end,
				 );

    $aln->add_seq($seq);

    return $aln;

}

sub write_aln {

    my ($self,@aln) = @_;

    $self->throw("Sorry: writing bl2seq output is not available! /n");

}

General documentation

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
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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/

Email: schattner@alum.mit.edu

The rest of the documentation details each of the object
methods. Internal methods are usually preceded with a _