Raw content of Bio::DB::GFF::Feature
<![CDATA[=head1 NAME
Bio::DB::GFF::Feature -- A relative segment identified by a feature type
=head1 SYNOPSIS
See L<Bio::DB::GFF>.
=head1 DESCRIPTION
Bio::DB::GFF::Feature is a stretch of sequence that corresponding to a
single annotation in a GFF database. It inherits from
Bio::DB::GFF::RelSegment, and so has all the support for relative
addressing of this class and its ancestors. It also inherits from
Bio::SeqFeatureI and so has the familiar start(), stop(),
primary_tag() and location() methods (it implements Bio::LocationI
too, if needed).
Bio::DB::GFF::Feature adds new methods to retrieve the annotation's
type, group, and other GFF attributes. Annotation types are
represented by Bio::DB::GFF::Typename objects, a simple class that has
two methods called method() and source(). These correspond to the
method and source fields of a GFF file.
Annotation groups serve the dual purpose of giving the annotation a
human-readable name, and providing higher-order groupings of
subfeatures into features. The groups returned by this module are
objects of the Bio::DB::GFF::Featname class.
Bio::DB::GFF::Feature inherits from and implements the abstract
methods of Bio::SeqFeatureI, allowing it to interoperate with other
Bioperl modules.
Generally, you will not create or manipulate Bio::DB::GFF::Feature
objects directly, but use those that are returned by the
Bio::DB::GFF::RelSegment-E<gt>features() method.
=head2 Important note about start() vs end()
If features are derived from segments that use relative addressing
(which is the default), then start() will be less than end() if the
feature is on the opposite strand from the reference sequence. This
breaks Bio::SeqI compliance, but is necessary to avoid having the real
genomic locations designated by start() and end() swap places when
changing reference points.
To avoid this behavior, call $segment-E<gt>absolute(1) before fetching
features from it. This will force everything into absolute
coordinates.
For example:
my $segment = $db->segment('CHROMOSOME_I');
$segment->absolute(1);
my @features = $segment->features('transcript');
=head1 API
The remainder of this document describes the public and private
methods implemented by this module.
=cut
package Bio::DB::GFF::Feature;
use strict;
use Bio::DB::GFF::Util::Rearrange;
use Bio::DB::GFF::RelSegment;
use Bio::DB::GFF::Featname;
use Bio::DB::GFF::Typename;
use Bio::DB::GFF::Homol;
use Bio::SeqFeatureI;
use Bio::Root::Root;
use Bio::LocationI;
use vars qw(@ISA $AUTOLOAD);
@ISA = qw(Bio::DB::GFF::RelSegment Bio::SeqFeatureI
Bio::Root::Root);
#'
*segments = \&sub_SeqFeature;
my %CONSTANT_TAGS = (method=>1, source=>1, score=>1, phase=>1, notes=>1, id=>1, group=>1);
=head2 new_from_parent
Title : new_from_parent
Usage : $f = Bio::DB::GFF::Feature->new_from_parent(@args);
Function: create a new feature object
Returns : new Bio::DB::GFF::Feature object
Args : see below
Status : Internal
This method is called by Bio::DB::GFF to create a new feature using
information obtained from the GFF database. It is one of two similar
constructors. This one is called when the feature is generated from a
RelSegment object, and should inherit that object's coordinate system.
The 13 arguments are positional (sorry):
$parent a Bio::DB::GFF::RelSegment object (or descendent)
$start start of this feature
$stop stop of this feature
$method this feature's GFF method
$source this feature's GFF source
$score this feature's score
$fstrand this feature's strand (relative to the source
sequence, which has its own strandedness!)
$phase this feature's phase
$group this feature's group (a Bio::DB::GFF::Featname object)
$db_id this feature's internal database ID
$group_id this feature's internal group database ID
$tstart this feature's target start
$tstop this feature's target stop
tstart and tstop aren't used for anything at the moment, since the
information is embedded in the group object.
=cut
# this is called for a feature that is attached to a parent sequence,
# in which case it inherits its coordinate reference system and strandedness
sub new_from_parent {
my $package = shift;
my ($parent,
$start,$stop,
$method,$source,$score,
$fstrand,$phase,
$group,$db_id,$group_id,
$tstart,$tstop) = @_;
($start,$stop) = ($stop,$start) if defined($fstrand) and $fstrand eq '-';
my $class = $group ? $group->class : $parent->class;
my $self = bless {
factory => $parent->{factory},
sourceseq => $parent->{sourceseq},
strand => $parent->{strand},
ref => $parent->{ref},
refstart => $parent->{refstart},
refstrand => $parent->{refstrand},
absolute => $parent->{absolute},
start => $start,
stop => $stop,
type => Bio::DB::GFF::Typename->new($method,$source),
fstrand => $fstrand,
score => $score,
phase => $phase,
group => $group,
db_id => $db_id,
group_id => $group_id,
class => $class,
},$package;
$self;
}
=head2 new
Title : new
Usage : $f = Bio::DB::GFF::Feature->new(@args);
Function: create a new feature object
Returns : new Bio::DB::GFF::Feature object
Args : see below
Status : Internal
This method is called by Bio::DB::GFF to create a new feature using
information obtained from the GFF database. It is one of two similar
constructors. This one is called when the feature is generated
without reference to a RelSegment object, and should therefore use its
default coordinate system (relative to itself).
The 11 arguments are positional:
$factory a Bio::DB::GFF adaptor object (or descendent)
$srcseq the source sequence
$start start of this feature
$stop stop of this feature
$method this feature's GFF method
$source this feature's GFF source
$score this feature's score
$fstrand this feature's strand (relative to the source
sequence, which has its own strandedness!)
$phase this feature's phase
$group this feature's group
$db_id this feature's internal database ID
=cut
# 'This is called when creating a feature from scratch. It does not have
# an inherited coordinate system.
sub new {
my $package = shift;
my ($factory,
$srcseq,
$start,$stop,
$method,$source,
$score,$fstrand,$phase,
$group,$db_id,$group_id,
$tstart,$tstop) = @_;
my $self = bless { },$package;
($start,$stop) = ($stop,$start) if defined($fstrand) and $fstrand eq '-';
my $class = $group ? $group->class : 'Sequence';
@{$self}{qw(factory sourceseq start stop strand class)} =
($factory,$srcseq,$start,$stop,$fstrand,$class);
# if the target start and stop are defined, then we use this information to create
# the reference sequence
# THIS SHOULD BE BUILT INTO RELSEGMENT
if (0 && $tstart ne '' && $tstop ne '') {
if ($tstart < $tstop) {
@{$self}{qw(ref refstart refstrand)} = ($group,$start - $tstart + 1,'+');
} else {
@{$self}{'start','stop'} = @{$self}{'stop','start'};
@{$self}{qw(ref refstart refstrand)} = ($group,$tstop + $stop - 1,'-');
}
} else {
@{$self}{qw(ref refstart refstrand)} = ($srcseq,1,'+');
}
@{$self}{qw(type fstrand score phase group db_id group_id absolute)} =
(Bio::DB::GFF::Typename->new($method,$source),$fstrand,$score,$phase,
$group,$db_id,$group_id,$factory->{absolute});
$self;
}
=head2 type
Title : type
Usage : $type = $f->type([$newtype])
Function: get or set the feature type
Returns : a Bio::DB::GFF::Typename object
Args : a new Typename object (optional)
Status : Public
This method gets or sets the type of the feature. The type is a
Bio::DB::GFF::Typename object, which encapsulates the feature method
and source.
The method() and source() methods described next provide shortcuts to
the individual fields of the type.
=cut
sub type {
my $self = shift;
my $d = $self->{type};
$self->{type} = shift if @_;
$d;
}
=head2 method
Title : method
Usage : $method = $f->method([$newmethod])
Function: get or set the feature method
Returns : a string
Args : a new method (optional)
Status : Public
This method gets or sets the feature method. It is a convenience
feature that delegates the task to the feature's type object.
=cut
sub method {
my $self = shift;
my $d = $self->{type}->method;
$self->{type}->method(shift) if @_;
$d;
}
=head2 source
Title : source
Usage : $source = $f->source([$newsource])
Function: get or set the feature source
Returns : a string
Args : a new source (optional)
Status : Public
This method gets or sets the feature source. It is a convenience
feature that delegates the task to the feature's type object.
=cut
sub source {
my $self = shift;
my $d = $self->{type}->source;
$self->{type}->source(shift) if @_;
$d;
}
=head2 score
Title : score
Usage : $score = $f->score([$newscore])
Function: get or set the feature score
Returns : a string
Args : a new score (optional)
Status : Public
This method gets or sets the feature score.
=cut
sub score {
my $self = shift;
my $d = $self->{score};
$self->{score} = shift if @_;
$d;
}
=head2 phase
Title : phase
Usage : $phase = $f->phase([$phase])
Function: get or set the feature phase
Returns : a string
Args : a new phase (optional)
Status : Public
This method gets or sets the feature phase.
=cut
sub phase {
my $self = shift;
my $d = $self->{phase};
$self->{phase} = shift if @_;
$d;
}
=head2 strand
Title : strand
Usage : $strand = $f->strand
Function: get the feature strand
Returns : +1, 0 -1
Args : none
Status : Public
Returns the strand of the feature. Unlike the other methods, the
strand cannot be changed once the object is created (due to coordinate
considerations).
=cut
sub strand {
my $self = shift;
return 0 unless $self->{fstrand};
if ($self->absolute) {
return Bio::DB::GFF::RelSegment::_to_strand($self->{fstrand});
}
return $self->SUPER::strand;
}
=head2 group
Title : group
Usage : $group = $f->group([$new_group])
Function: get or set the feature group
Returns : a Bio::DB::GFF::Featname object
Args : a new group (optional)
Status : Public
This method gets or sets the feature group. The group is a
Bio::DB::GFF::Featname object, which has an ID and a class.
=cut
sub group {
my $self = shift;
my $d = $self->{group};
$self->{group} = shift if @_;
$d;
}
=head2 display_id
Title : display_id
Usage : $display_id = $f->display_id([$display_id])
Function: get or set the feature display id
Returns : a Bio::DB::GFF::Featname object
Args : a new display_id (optional)
Status : Public
This method is an alias for group(). It is provided for
Bio::SeqFeatureI compatibility.
=cut
=head2 info
Title : info
Usage : $info = $f->info([$new_info])
Function: get or set the feature group
Returns : a Bio::DB::GFF::Featname object
Args : a new group (optional)
Status : Public
This method is an alias for group(). It is provided for AcePerl
compatibility.
=cut
*info = \&group;
*display_id = \&group;
*display_name = \&group;
=head2 target
Title : target
Usage : $target = $f->target([$new_target])
Function: get or set the feature target
Returns : a Bio::DB::GFF::Featname object
Args : a new group (optional)
Status : Public
This method works like group(), but only returns the group if it
implements the start() method. This is typical for
similarity/assembly features, where the target encodes the start and stop
location of the alignment.
=cut
sub target {
my $self = shift;
my $group = $self->group or return;
return unless $group->can('start');
$group;
}
=head2 hit
Title : hit
Usage : $hit = $f->hit([$new_hit])
Function: get or set the feature hit
Returns : a Bio::DB::GFF::Featname object
Args : a new group (optional)
Status : Public
This is the same as target(), for compatibility with
Bio::SeqFeature::SimilarityPair.
=cut
*hit = \⌖
=head2 id
Title : id
Usage : $id = $f->id
Function: get the feature ID
Returns : a database identifier
Args : none
Status : Public
This method retrieves the database identifier for the feature. It
cannot be changed.
=cut
sub id { shift->{db_id} }
=head2 group_id
Title : group_id
Usage : $id = $f->group_id
Function: get the feature ID
Returns : a database identifier
Args : none
Status : Public
This method retrieves the database group identifier for the feature.
It cannot be changed. Often the group identifier is more useful than
the feature identifier, since it is used to refer to a complex object
containing subparts.
=cut
sub group_id { shift->{group_id} }
=head2 clone
Title : clone
Usage : $feature = $f->clone
Function: make a copy of the feature
Returns : a new Bio::DB::GFF::Feature object
Args : none
Status : Public
This method returns a copy of the feature.
=cut
sub clone {
my $self = shift;
my $clone = $self->SUPER::clone;
if (ref(my $t = $clone->type)) {
my $type = $t->can('clone') ? $t->clone : bless {%$t},ref $t;
$clone->type($type);
}
if (ref(my $g = $clone->group)) {
my $group = $g->can('clone') ? $g->clone : bless {%$g},ref $g;
$clone->group($group);
}
if (my $merged = $self->{merged_segs}) {
$clone->{merged_segs} = { %$merged };
}
$clone;
}
=head2 compound
Title : compound
Usage : $flag = $f->compound([$newflag])
Function: get or set the compound flag
Returns : a boolean
Args : a new flag (optional)
Status : Public
This method gets or sets a flag indicated that the feature is not a
primary one from the database, but the result of aggregation.
=cut
sub compound {
my $self = shift;
my $d = $self->{compound};
$self->{compound} = shift if @_;
$d;
}
=head2 sub_SeqFeature
Title : sub_SeqFeature
Usage : @feat = $feature->sub_SeqFeature([$method])
Function: get subfeatures
Returns : a list of Bio::DB::GFF::Feature objects
Args : a feature method (optional)
Status : Public
This method returns a list of any subfeatures that belong to the main
feature. For those features that contain heterogeneous subfeatures,
you can retrieve a subset of the subfeatures by providing a method
name to filter on.
For AcePerl compatibility, this method may also be called as
segments().
=cut
sub sub_SeqFeature {
my $self = shift;
my $type = shift;
my $subfeat = $self->{subfeatures} or return;
$self->sort_features;
my @a;
if ($type) {
my $features = $subfeat->{lc $type} or return;
@a = @{$features};
} else {
@a = map {@{$_}} values %{$subfeat};
}
return @a;
}
=head2 add_subfeature
Title : add_subfeature
Usage : $feature->add_subfeature($feature)
Function: add a subfeature to the feature
Returns : nothing
Args : a Bio::DB::GFF::Feature object
Status : Public
This method adds a new subfeature to the object. It is used
internally by aggregators, but is available for public use as well.
=cut
sub add_subfeature {
my $self = shift;
my $feature = shift;
my $type = $feature->method;
my $subfeat = $self->{subfeatures}{lc $type} ||= [];
push @{$subfeat},$feature;
}
=head2 attach_seq
Title : attach_seq
Usage : $sf->attach_seq($seq)
Function: Attaches a Bio::Seq object to this feature. This
Bio::Seq object is for the *entire* sequence: ie
from 1 to 10000
Example :
Returns : TRUE on success
Args : a Bio::PrimarySeqI compliant object
=cut
sub attach_seq { }
=head2 location
Title : location
Usage : my $location = $seqfeature->location()
Function: returns a location object suitable for identifying location
of feature on sequence or parent feature
Returns : Bio::LocationI object
Args : none
=cut
sub location {
my $self = shift;
require Bio::Location::Split unless Bio::Location::Split->can('new');
require Bio::Location::Simple unless Bio::Location::Simple->can('new');
my $location;
if (my @segments = $self->segments) {
$location = Bio::Location::Split->new(-seq_id => $self->seq_id);
foreach (@segments) {
$location->add_sub_Location($_->location);
}
} else {
$location = Bio::Location::Simple->new(-start => $self->start,
-end => $self->stop,
-strand => $self->strand,
-seq_id => $self->seq_id);
}
$location;
}
=head2 entire_seq
Title : entire_seq
Usage : $whole_seq = $sf->entire_seq()
Function: gives the entire sequence that this seqfeature is attached to
Example :
Returns : a Bio::PrimarySeqI compliant object, or undef if there is no
sequence attached
Args : none
=cut
sub entire_seq {
my $self = shift;
$self->factory->segment($self->sourceseq);
}
=head2 merged_segments
Title : merged_segments
Usage : @segs = $feature->merged_segments([$method])
Function: get merged subfeatures
Returns : a list of Bio::DB::GFF::Feature objects
Args : a feature method (optional)
Status : Public
This method acts like sub_SeqFeature, except that it merges
overlapping segments of the same time into contiguous features. For
those features that contain heterogeneous subfeatures, you can
retrieve a subset of the subfeatures by providing a method name to
filter on.
A side-effect of this method is that the features are returned in
sorted order by their start tposition.
=cut
#'
sub merged_segments {
my $self = shift;
my $type = shift;
$type ||= ''; # prevent uninitialized variable warnings
my $truename = overload::StrVal($self);
return @{$self->{merged_segs}{$type}} if exists $self->{merged_segs}{$type};
my @segs = map { $_->[0] }
sort { $a->[1] <=> $b->[1] ||
$a->[2] cmp $b->[2] }
map { [$_, $_->start, $_->type] } $self->sub_SeqFeature($type);
# attempt to merge overlapping segments
my @merged = ();
for my $s (@segs) {
my $previous = $merged[-1] if @merged;
my ($pscore,$score) = (eval{$previous->score}||0,eval{$s->score}||0);
if (defined($previous)
&& $previous->stop+1 >= $s->start
&& (!defined($s->score) || $previous->score == $s->score)
&& $previous->method eq $s->method
) {
if ($self->absolute && $self->strand < 0) {
$previous->{start} = $s->{start};
} else {
$previous->{stop} = $s->{stop};
}
# fix up the target too
my $g = $previous->{group};
if ( ref($g) && $g->isa('Bio::DB::GFF::Homol')) {
my $cg = $s->{group};
$g->{stop} = $cg->{stop};
}
} elsif (defined($previous)
&& $previous->start == $s->start
&& $previous->stop == $s->stop) {
next;
} else {
my $copy = $s->clone;
push @merged,$copy;
}
}
$self->{merged_segs}{$type} = \@merged;
@merged;
}
=head2 sub_types
Title : sub_types
Usage : @methods = $feature->sub_types
Function: get methods of all sub-seqfeatures
Returns : a list of method names
Args : none
Status : Public
For those features that contain subfeatures, this method will return a
unique list of method names of those subfeatures, suitable for use
with sub_SeqFeature().
=cut
sub sub_types {
my $self = shift;
my $subfeat = $self->{subfeatures} or return;
return keys %$subfeat;
}
=head2 attributes
Title : attributes
Usage : @attributes = $feature->attributes($name)
Function: get the "attributes" on a particular feature
Returns : an array of string
Args : feature ID
Status : public
Some GFF version 2 files use the groups column to store a series of
attribute/value pairs. In this interpretation of GFF, the first such
pair is treated as the primary group for the feature; subsequent pairs
are treated as attributes. Two attributes have special meaning:
"Note" is for backward compatibility and is used for unstructured text
remarks. "Alias" is considered as a synonym for the feature name.
@gene_names = $feature->attributes('Gene');
@aliases = $feature->attributes('Alias');
If no name is provided, then attributes() returns a flattened hash, of
attribute=E<gt>value pairs. This lets you do:
%attributes = $db->attributes;
=cut
sub attributes {
my $self = shift;
my $factory = $self->factory;
defined(my $id = $self->id) or return;
$factory->attributes($id,@_)
}
=head2 notes
Title : notes
Usage : @notes = $feature->notes
Function: get the "notes" on a particular feature
Returns : an array of string
Args : feature ID
Status : public
Some GFF version 2 files use the groups column to store various notes
and remarks. Adaptors can elect to store the notes in the database,
or just ignore them. For those adaptors that store the notes, the
notes() method will return them as a list.
=cut
sub notes {
my $self = shift;
$self->attributes('Note');
}
=head2 aliases
Title : aliases
Usage : @aliases = $feature->aliases
Function: get the "aliases" on a particular feature
Returns : an array of string
Args : feature ID
Status : public
This method will return a list of attributes of type 'Alias'.
=cut
sub aliases {
my $self = shift;
$self->attributes('Alias');
}
=head2 Autogenerated Methods
Title : AUTOLOAD
Usage : @subfeat = $feature->Method
Function: Return subfeatures using autogenerated methods
Returns : a list of Bio::DB::GFF::Feature objects
Args : none
Status : Public
Any method that begins with an initial capital letter will be passed
to AUTOLOAD and treated as a call to sub_SeqFeature with the method
name used as the method argument. For instance, this call:
@exons = $feature->Exon;
is equivalent to this call:
@exons = $feature->sub_SeqFeature('exon');
=cut
=head2 SeqFeatureI methods
The following Bio::SeqFeatureI methods are implemented:
primary_tag(), source_tag(), all_tags(), has_tag(), each_tag_value() [renamed get_tag_values()].
=cut
*primary_tag = \&method;
*source_tag = \&source;
sub all_tags {
my $self = shift;
my @tags = keys %CONSTANT_TAGS;
# autogenerated methods
if (my $subfeat = $self->{subfeatures}) {
push @tags,keys %$subfeat;
}
@tags;
}
*get_all_tags = \&all_tags;
sub has_tag {
my $self = shift;
my $tag = shift;
my %tags = map {$_=>1} $self->all_tags;
return $tags{$tag};
}
*each_tag_value = \&get_tag_values;
sub get_tag_values {
my $self = shift;
my $tag = shift;
return $self->$tag() if $CONSTANT_TAGS{$tag};
$tag = ucfirst $tag;
return $self->$tag(); # try autogenerated tag
}
sub AUTOLOAD {
my($pack,$func_name) = $AUTOLOAD=~/(.+)::([^:]+)$/;
my $sub = $AUTOLOAD;
my $self = $_[0];
# ignore DESTROY calls
return if $func_name eq 'DESTROY';
# fetch subfeatures if func_name has an initial cap
# return sort {$a->start <=> $b->start} $self->sub_SeqFeature($func_name) if $func_name =~ /^[A-Z]/;
return $self->sub_SeqFeature($func_name) if $func_name =~ /^[A-Z]/;
# error message of last resort
$self->throw(qq(Can't locate object method "$func_name" via package "$pack"));
}#'
=head2 adjust_bounds
Title : adjust_bounds
Usage : $feature->adjust_bounds
Function: adjust the bounds of a feature
Returns : ($start,$stop,$strand)
Args : none
Status : Public
This method adjusts the boundaries of the feature to enclose all its
subfeatures. It returns the new start, stop and strand of the
enclosing feature.
=cut
# adjust a feature so that its boundaries are synched with its subparts' boundaries.
# this works recursively, so subfeatures can contain other features
sub adjust_bounds {
my $self = shift;
my $g = $self->{group};
if (my $subfeat = $self->{subfeatures}) {
for my $list (values %$subfeat) {
for my $feat (@$list) {
# fix up our bounds to hold largest subfeature
my($start,$stop,$strand) = $feat->adjust_bounds;
$self->{fstrand} = $strand unless defined $self->{fstrand};
my ($low,$high) = $start < $stop ? ($start,$stop) : ($stop,$start);
if ($self->{fstrand} ne '-') {
$self->{start} = $low if !defined($self->{start}) || $low < $self->{start};
$self->{stop} = $high if !defined($self->{stop}) || $high > $self->{stop};
} else {
$self->{start} = $high if !defined($self->{start}) || $high > $self->{start};
$self->{stop} = $low if !defined($self->{stop}) || $low < $self->{stop};
}
# fix up endpoints of targets too (for homologies only)
my $h = $feat->group;
next unless $h && $h->isa('Bio::DB::GFF::Homol');
next unless $g && $g->isa('Bio::DB::GFF::Homol');
($start,$stop) = ($h->{start},$h->{stop});
if ($start <= $stop) {
$g->{start} = $start if !defined($g->{start}) || $start < $g->{start};
$g->{stop} = $stop if !defined($g->{stop}) || $stop > $g->{stop};
} else {
$g->{start} = $start if !defined($g->{start}) || $start > $g->{start};
$g->{stop} = $stop if !defined($g->{stop}) || $stop < $g->{stop};
}
}
}
}
($self->{start},$self->{stop},$self->strand);
}
=head2 sort_features
Title : sort_features
Usage : $feature->sort_features
Function: sort features
Returns : nothing
Args : none
Status : Public
This method sorts subfeatures in ascending order by their start
position. For reverse strand features, it sorts subfeatures in
descending order. After this is called sub_SeqFeature will return the
features in order.
This method is called internally by merged_segments().
=cut
# sort features
sub sort_features {
my $self = shift;
return if $self->{sorted}++;
my $strand = $self->strand or return;
my $subfeat = $self->{subfeatures} or return;
for my $type (keys %$subfeat) {
$subfeat->{$type} = [map { $_->[0] }
sort {$a->[1] <=> $b->[1] }
map { [$_,$_->start] }
@{$subfeat->{$type}}] if $strand > 0;
$subfeat->{$type} = [map { $_->[0] }
sort {$b->[1] <=> $a->[1]}
map { [$_,$_->start] }
@{$subfeat->{$type}}] if $strand < 0;
}
}
=head2 asString
Title : asString
Usage : $string = $feature->asString
Function: return human-readabled representation of feature
Returns : a string
Args : none
Status : Public
This method returns a human-readable representation of the feature and
is called by the overloaded "" operator.
=cut
sub asString {
my $self = shift;
my $type = $self->type;
my $name = $self->group;
return "$type($name)" if $name;
return $type;
# my $type = $self->method;
# my $id = $self->group || 'unidentified';
# return join '/',$id,$type,$self->SUPER::asString;
}
sub name {
my $self =shift;
return $self->group || $self->SUPER::name;
}
sub gff_string {
my $self = shift;
my ($start,$stop) = ($self->start,$self->stop);
# the defined() tests prevent uninitialized variable warnings, when dealing with clone objects
# whose endpoints may be undefined
($start,$stop) = ($stop,$start) if defined($start) && defined($stop) && $start > $stop;
my ($class,$name) = ('','');
my @group;
if (my $t = $self->target) {
my $class = $t->class;
my $name = $t->name;
my $start = $t->start;
my $stop = $t->stop;
push @group,qq(Target "$class:$name" $start $stop);
}
elsif (my $g = $self->group) {
$class = $g->class || '';
$name = $g->name || '';
push @group,"$class $name";
}
push @group,map {qq(Note "$_")} $self->notes;
my $group_field = join ' ; ',@group;
my $strand = ('-','.','+')[$self->strand+1];
my $ref = $self->refseq;
my $n = ref($ref) ? $ref->name : $ref;
my $phase = $self->phase;
$phase = '.' unless defined $phase;
return join("\t",$n,$self->source,$self->method,$start||'.',$stop||'.',$self->score||'.',$strand||'.',$phase,$group_field);
}
=head1 A Note About Similarities
The current default aggregator for GFF "similarity" features creates a
composite Bio::DB::GFF::Feature object of type "gapped_alignment".
The target() method for the feature as a whole will return a
RelSegment object that is as long as the extremes of the similarity
hit target, but will not necessarily be the same length as the query
sequence. The length of each "similarity" subfeature will be exactly
the same length as its target(). These subfeatures are essentially
the HSPs of the match.
The following illustrates this:
@similarities = $segment->feature('similarity:BLASTN');
$sim = $similarities[0];
print $sim->type; # yields "gapped_similarity:BLASTN"
$query_length = $sim->length;
$target_length = $sim->target->length; # $query_length != $target_length
@matches = $sim->Similarity; # use autogenerated method
$query1_length = $matches[0]->length;
$target1_length = $matches[0]->target->length; # $query1_length == $target1_length
If you merge segments by calling merged_segments(), then the length of
the query sequence segments will no longer necessarily equal the
length of the targets, because the alignment information will have
been lost. Nevertheless, the targets are adjusted so that the first
and last base pairs of the query match the first and last base pairs
of the target.
=cut
1;
=head1 BUGS
This module is still under development.
=head1 SEE ALSO
L<bioperl>, L<Bio::DB::GFF>, L<Bio::DB::RelSegment>
=head1 AUTHOR
Lincoln Stein E<lt>lstein@cshl.orgE<gt>.
Copyright (c) 2001 Cold Spring Harbor Laboratory.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
]]>