/ 
bioperl-1.5.2_004-RCd
/ Bio::SimpleAlign

NAME

Bio::SimpleAlign - Multiple alignments held as a set of sequences

SYNOPSIS

# Use Bio::AlignIO to read in the alignment
$str = Bio::AlignIO->new(-file => 't/data/testaln.pfam');
$aln = $str->next_aln();

# Describe
print $aln->length;
print $aln->no_residues;
print $aln->is_flush;
print $aln->no_sequences;
print $aln->score;
print $aln->percentage_identity;
print $aln->consensus_string(50);

# Find the position in the alignment for a sequence location
$pos = $aln->column_from_residue_number('1433_LYCES', 14); # = 6;

# Extract sequences and check values for the alignment column $pos
foreach $seq ($aln->each_seq) {
    $res = $seq->subseq($pos, $pos);
    $count{$res}++;
}
foreach $res (keys %count) {
    printf "Res: %s  Count: %2d\n", $res, $count{$res};
}

# Manipulate
$aln->remove_seq($seq);
$mini_aln = $aln->slice(20,30);  # get a block of columns
$mini_aln = $aln->select_noncont(1,3,5,7,11); # get single columns
$new_aln = $aln->remove_columns([20,30]); # remove by position
$new_aln = $aln->remove_columns(['mismatch']); # remove by property

# Analyze
$str = $aln->consensus_string($threshold_percent);
$str = $aln->match_line();
$str = $aln->cigar_line()
$id = $aln->percentage_identity;

See the module documentation for details and more methods.

DESCRIPTION

SimpleAlign is an object that handles a multiple sequence alignment (MSA). It is very permissive of types (it does not insist on sequences being all same length, for example). Think of it as a set of sequences with a whole series of built-in manipulations and methods for reading and writing alignments.

SimpleAlign uses Bio::LocatableSeq, a subclass of Bio::PrimarySeq, to store its sequences. These are subsequences with a start and end positions in the parent reference sequence. Each sequence in the SimpleAlign object is a Bio::LocatableSeq.

SimpleAlign expects the combination of name, start, and end for a given sequence to be unique in the alignment, and this is the key for the internal hashes (name, start, end are abbreviated nse in the code). However, in some cases people do not want the name/start-end to be displayed: either multiple names in an alignment or names specific to the alignment (ROA1_HUMAN_1, ROA1_HUMAN_2 etc). These names are called displayname, and generally is what is used to print out the alignment. They default to name/start-end.

The SimpleAlign Module is derived from the Align module by Ewan Birney.

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://bioperl.org/wiki/Mailing_lists  - 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 the web:

http://bugzilla.open-bio.org/

AUTHOR

Ewan Birney, birney@ebi.ac.uk

CONTRIBUTORS

Allen Day, allenday-at-ucla.edu, Richard Adams, Richard.Adams-at-ed.ac.uk, David J. Evans, David.Evans-at-vir.gla.ac.uk, Heikki Lehvaslaiho, heikki-at-bioperl-dot-org, Allen Smith, allens-at-cpan.org, Jason Stajich, jason-at-bioperl.org, Anthony Underwood, aunderwood-at-phls.org.uk, Xintao Wei & Giri Narasimhan, giri-at-cs.fiu.edu Brian Osborne, bosborne at alum.mit.edu

SEE ALSO

Bio::LocatableSeq

APPENDIX

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

new

Title     : new
Usage     : my $aln = new Bio::SimpleAlign();
Function  : Creates a new simple align object
Returns   : Bio::SimpleAlign
Args      : -source => string representing the source program
                       where this alignment came from

Modifier methods

These methods modify the MSA by adding, removing or shuffling complete sequences.

add_seq

Title     : add_seq
Usage     : $myalign->add_seq($newseq);
Function  : Adds another sequence to the alignment. *Does not* align
            it - just adds it to the hashes.
Returns   : nothing
Args      : a Bio::LocatableSeq object
            order (optional)

See Bio::LocatableSeq for more information

remove_seq

Title     : remove_seq
Usage     : $aln->remove_seq($seq);
Function  : Removes a single sequence from an alignment
Returns   :
Argument  : a Bio::LocatableSeq object

purge

Title   : purge
Usage   : $aln->purge(0.7);
Function: Removes sequences above given sequence similarity
          This function will grind on large alignments. Beware!
Example :
Returns : An array of the removed sequences
Args    : float, threshold for similarity

sort_alphabetically

Title     : sort_alphabetically
Usage     : $ali->sort_alphabetically
Function  : Changes the order of the alignemnt to alphabetical on name
            followed by numerical by number.
Returns   :
Argument  :

set_new_reference

Title     : set_new_reference
Usage     : $aln->set_new_reference(3 or 'B31'):  Select the 3rd sequence, or
            the sequence whoes name is "B31" (full, exact, and case-sensitive),
            as the reference (1st) sequence
Function  : Change/Set a new reference (i.e., the first) sequence
Returns   : a new Bio::SimpleAlign object.
            Throws an exception if designated sequence not found
Argument  : a positive integer of sequence order, or a sequence name
            in the original alignment

uniq_seq

Title     : uniq_seq
Usage     : $aln->uniq_seq():  Remove identical sequences in
            in the alignment.  Ambiguous base ("N", "n") and
            leading and ending gaps ("-") are NOT counted as
            differences.
Function  : Make a new alignment of unique sequence types (STs)
Returns   : 1. a new Bio::SimpleAlign object (all sequences renamed as "ST")
            2. ST of each sequence in STDERR
Argument  : None

Sequence selection methods

Methods returning one or more sequences objects.

each_seq

Title     : each_seq
Usage     : foreach $seq ( $align->each_seq() )
Function  : Gets a Seq object from the alignment
Returns   : Seq object
Argument  :

each_alphabetically

Title     : each_alphabetically
Usage     : foreach $seq ( $ali->each_alphabetically() )
Function  : Returns a sequence object, but the objects are returned
            in alphabetically sorted order.
            Does not change the order of the alignment.
Returns   : Seq object
Argument  :

each_seq_with_id

Title     : each_seq_with_id
Usage     : foreach $seq ( $align->each_seq_with_id() )
Function  : Gets a Seq objects from the alignment, the contents
            being those sequences with the given name (there may be
            more than one)
Returns   : Seq object
Argument  : a seq name

get_seq_by_pos

Title     : get_seq_by_pos
Usage     : $seq = $aln->get_seq_by_pos(3) # third sequence from the alignment
Function  : Gets a sequence based on its position in the alignment.
            Numbering starts from 1.  Sequence positions larger than
            no_sequences() will thow an error.
Returns   : a Bio::LocatableSeq object
Args      : positive integer for the sequence osition

seq_with_features

Title   : seq_with_features
Usage   : $seq = $aln->seq_with_features(-pos => 1,
                                         -consensus => 60
                                         -mask =>
          sub { my $consensus = shift;

                for my $i (1..5){
                   my $n = 'N' x $i;
                   my $q = '\?' x $i;
                   while($consensus =~ /[^?]$q[^?]/){
                      $consensus =~ s/([^?])$q([^?])/$1$n$2/;
                   }
                 }
                return $consensus;
              }
                                        );
Function: produces a Bio::Seq object by first splicing gaps from -pos
          (by means of a splice_by_seq_pos() call), then creating
          features using non-? chars (by means of a consensus_string()
          call with stringency -consensus).
Returns : a Bio::Seq object
Args    : -pos : required. sequence from which to build the Bio::Seq
            object
          -consensus : optional, defaults to consensus_string()'s
            default cutoff value
          -mask : optional, a coderef to apply to consensus_string()'s
            output before building features.  this may be useful for
            closing gaps of 1 bp by masking over them with N, for
            instance

Create new alignments

The result of these methods are horizontal or vertical subsets of the current MSA.

select

Title     : select
Usage     : $aln2 = $aln->select(1, 3) # three first sequences
Function  : Creates a new alignment from a continuous subset of
            sequences.  Numbering starts from 1.  Sequence positions
            larger than no_sequences() will thow an error.
Returns   : a Bio::SimpleAlign object
Args      : positive integer for the first sequence
            positive integer for the last sequence to include (optional)

select_noncont

Title     : select_noncont
Usage     : $aln2 = $aln->select_noncont(1, 3) # 1st and 3rd sequences
Function  : Creates a new alignment from a subset of
            sequences.  Numbering starts from 1.  Sequence positions
            larger than no_sequences() will thow an error.
Returns   : a Bio::SimpleAlign object
Args      : array of integers for the sequences

slice

Title     : slice
Usage     : $aln2 = $aln->slice(20,30)
Function  : Creates a slice from the alignment inclusive of start and
            end columns, and the first column in the alignment is denoted 1.
            Sequences with no residues in the slice are excluded from the
            new alignment and a warning is printed. Slice beyond the length of
            the sequence does not do padding.
Returns   : A Bio::SimpleAlign object
Args      : Positive integer for start column, positive integer for end column,
            optional boolean which if true will keep gap-only columns in the newly
            created slice. Example:

            $aln2 = $aln->slice(20,30,1)

remove_columns

Title     : remove_columns
Usage     : $aln2 = $aln->remove_columns(['mismatch','weak']) or
            $aln2 = $aln->remove_columns([0,0],[6,8])
Function  : Creates an aligment with columns removed corresponding to
            the specified type or by specifying the columns by number.
Returns   : Bio::SimpleAlign object
Args      : Array ref of types ('match'|'weak'|'strong'|'mismatch'|'gaps'|
            'all_gaps_columns') or array ref where the referenced array
            contains a pair of integers that specify a range.
            The first column is 0,

remove_gaps

Title     : remove_gaps
Usage     : $aln2 = $aln->remove_gaps
Function  : Creates an aligment with gaps removed
Returns   : a Bio::SimpleAlign object
Args      : a gap character(optional) if none specified taken
               from $self->gap_char,
            [optional] $all_gaps_columns flag (1 or 0, default is 0)
                       indicates that only all-gaps columns should be deleted

Used from method remove_columns in most cases. Set gap character using gap_char().

Change sequences within the MSA

These methods affect characters in all sequences without changing the alignment.

splice_by_seq_pos

Title   : splice_by_seq_pos
Usage   : $status = splice_by_seq_pos(1);
Function: splices all aligned sequences where the specified sequence
          has gaps.
Example :
Returns : 1 on success
Args    : position of sequence to splice by

map_chars

Title     : map_chars
Usage     : $ali->map_chars('\.','-')
Function  : Does a s/$arg1/$arg2/ on the sequences. Useful for gap
            characters

            Notice that the from (arg1) is interpretted as a regex,
            so be careful about quoting meta characters (eg
            $ali->map_chars('.','-') wont do what you want)
Returns   :
Argument  : 'from' rexexp
            'to' string

uppercase

Title     : uppercase()
Usage     : $ali->uppercase()
Function  : Sets all the sequences to uppercase
Returns   :
Argument  :

cigar_line

Title    : cigar_line()
Usage    : %cigars = $align->cigar_line()
Function : Generates a "cigar" (Compact Idiosyncratic Gapped Alignment
           Report) line for each sequence in the alignment. Examples are
           "1,60" or "5,10:12,58", where the numbers refer to conserved
           positions within the alignment. The keys of the hash are the
           NSEs (name/start/end) assigned to each sequence.
Args     : none
Returns  : Hash of strings (cigar lines)

match_line

Title    : match_line()
Usage    : $line = $align->match_line()
Function : Generates a match line - much like consensus string
           except that a line indicating the '*' for a match.
Args     : (optional) Match line characters ('*' by default)
           (optional) Strong match char (':' by default)
           (optional) Weak match char ('.' by default)
Returns  : String

gap_line

Title    : gap_line()
Usage    : $line = $align->gap_line()
Function : Generates a gap line - much like consensus string
           except that a line where '-' represents gap
Args     : (optional) gap line characters ('-' by default)
Returns  : string

all_gap_line

Title    : all_gap_line()
Usage    : $line = $align->all_gap_line()
Function : Generates a gap line - much like consensus string
           except that a line where '-' represents all-gap column
Args     : (optional) gap line characters ('-' by default)
Returns  : string

gap_col_matrix

Title    : gap_col_matrix()
Usage    : my $cols = $align->gap_col_matrix()
Function : Generates an array of hashes where
           each entry in the array is a hash reference
           with keys of all the sequence names and
           and value of 1 or 0 if the sequence has a gap at that column
Args     : (optional) gap line characters ($aln->gap_char or '-' by default)

match

Title     : match()
Usage     : $ali->match()
Function  : Goes through all columns and changes residues that are
            identical to residue in first sequence to match '.'
            character. Sets match_char.

            USE WITH CARE: Most MSA formats do not support match
            characters in sequences, so this is mostly for output
            only. NEXUS format (Bio::AlignIO::nexus) can handle
            it.
Returns   : 1
Argument  : a match character, optional, defaults to '.'

unmatch

Title     : unmatch()
Usage     : $ali->unmatch()
Function  : Undoes the effect of method match. Unsets match_char.
Returns   : 1
Argument  : a match character, optional, defaults to '.'

See match and match_char

MSA attibutes

Methods for setting and reading the MSA attributes.

Note that the methods defining character semantics depend on the user to set them sensibly. They are needed only by certain input/output methods. Unset them by setting to an empty string ('').

id

Title     : id
Usage     : $myalign->id("Ig")
Function  : Gets/sets the id field of the alignment
Returns   : An id string
Argument  : An id string (optional)

accession

Title     : accession
Usage     : $myalign->accession("PF00244")
Function  : Gets/sets the accession field of the alignment
Returns   : An acc string
Argument  : An acc string (optional)

description

Title     : description
Usage     : $myalign->description("14-3-3 proteins")
Function  : Gets/sets the description field of the alignment
Returns   : An description string
Argument  : An description string (optional)

missing_char

Title     : missing_char
Usage     : $myalign->missing_char("?")
Function  : Gets/sets the missing_char attribute of the alignment
            It is generally recommended to set it to 'n' or 'N'
            for nucleotides and to 'X' for protein.
Returns   : An missing_char string,
Argument  : An missing_char string (optional)

match_char

Title     : match_char
Usage     : $myalign->match_char('.')
Function  : Gets/sets the match_char attribute of the alignment
Returns   : An match_char string,
Argument  : An match_char string (optional)

gap_char

Title     : gap_char
Usage     : $myalign->gap_char('-')
Function  : Gets/sets the gap_char attribute of the alignment
Returns   : An gap_char string, defaults to '-'
Argument  : An gap_char string (optional)

symbol_chars

Title   : symbol_chars
Usage   : my @symbolchars = $aln->symbol_chars;
Function: Returns all the seen symbols (other than gaps)
Returns : array of characters that are the seen symbols
Args    : boolean to include the gap/missing/match characters

Alignment descriptors

These read only methods describe the MSA in various ways.

score

Title     : score
Usage     : $str = $ali->score()
Function  : get/set a score of the alignment
Returns   : a score for the alignment
Argument  : an optional score to set

consensus_string

Title     : consensus_string
Usage     : $str = $ali->consensus_string($threshold_percent)
Function  : Makes a strict consensus
Returns   : Consensus string
Argument  : Optional treshold ranging from 0 to 100.
            The consensus residue has to appear at least threshold %
            of the sequences at a given location, otherwise a '?'
            character will be placed at that location.
            (Default value = 0%)

consensus_iupac

Title     : consensus_iupac
Usage     : $str = $ali->consensus_iupac()
Function  : Makes a consensus using IUPAC ambiguity codes from DNA
            and RNA. The output is in upper case except when gaps in
            a column force output to be in lower case.

            Note that if your alignment sequences contain a lot of
            IUPAC ambiquity codes you often have to manually set
            alphabet.  Bio::PrimarySeq::_guess_type thinks they
            indicate a protein sequence.
Returns   : consensus string
Argument  : none
Throws    : on protein sequences

consensus_meta

Title     : consensus_meta
Usage     : $seqmeta = $ali->consensus_meta()
Function  : Returns a Bio::Seq::Meta object containing the consensus
            strings derived from meta data analysis.
Returns   : Bio::Seq::Meta 
Argument  : Bio::Seq::Meta 
Throws    : non-MetaI object

is_flush

Title     : is_flush
Usage     : if ( $ali->is_flush() )
Function  : Tells you whether the alignment
          : is flush, i.e. all of the same length
Returns   : 1 or 0
Argument  :

length

Title     : length()
Usage     : $len = $ali->length()
Function  : Returns the maximum length of the alignment.
            To be sure the alignment is a block, use is_flush
Returns   : Integer
Argument  :

maxdisplayname_length

Title     : maxdisplayname_length
Usage     : $ali->maxdisplayname_length()
Function  : Gets the maximum length of the displayname in the
            alignment. Used in writing out various MSA formats.
Returns   : integer
Argument  :

max_metaname_length

Title     : max_metaname_length
Usage     : $ali->max_metaname_length()
Function  : Gets the maximum length of the meta name tags in the
            alignment for the sequences and for the alignment.
            Used in writing out various MSA formats.
Returns   : integer
Argument  : None

no_residues

Title     : no_residues
Usage     : $no = $ali->no_residues
Function  : number of residues in total in the alignment
Returns   : integer
Argument  :

no_sequences

Title     : no_sequences
Usage     : $depth = $ali->no_sequences
Function  : number of sequence in the sequence alignment
Returns   : integer
Argument  :

average_percentage_identity

Title   : average_percentage_identity
Usage   : $id = $align->average_percentage_identity
Function: The function uses a fast method to calculate the average
          percentage identity of the alignment
Returns : The average percentage identity of the alignment
Args    : None
Notes   : This method implemented by Kevin Howe calculates a figure that is
          designed to be similar to the average pairwise identity of the
          alignment (identical in the absence of gaps), without having to
          explicitly calculate pairwise identities proposed by Richard Durbin.
          Validated by Ewan Birney ad Alex Bateman.

percentage_identity

Title   : percentage_identity
Usage   : $id = $align->percentage_identity
Function: The function calculates the average percentage identity
          (aliased to average_percentage_identity)
Returns : The average percentage identity
Args    : None

overall_percentage_identity

Title   : percentage_identity
Usage   : $id = $align->percentage_identity
Function: The function calculates the percentage identity of
          the conserved columns
Returns : The percentage identity of the conserved columns
Args    : None

Alignment positions

Methods to map a sequence position into an alignment column and back. column_from_residue_number() does the former. The latter is really a property of the sequence object and can done using Bio::LocatableSeq::location_from_column:

# select somehow a sequence from the alignment, e.g.
my $seq = $aln->get_seq_by_pos(1);
#$loc is undef or Bio::LocationI object
my $loc = $seq->location_from_column(5);

column_from_residue_number

 Title   : column_from_residue_number
 Usage   : $col = $ali->column_from_residue_number( $seqname, $resnumber)
 Function: This function gives the position in the alignment
           (i.e. column number) of the given residue number in the
           sequence with the given name. For example, for the
           alignment

    	     Seq1/91-97 AC..DEF.GH.
   	     Seq2/24-30 ACGG.RTY...
  	        Seq3/43-51 AC.DDEF.GHI

           column_from_residue_number( "Seq1", 94 ) returns 6.
           column_from_residue_number( "Seq2", 25 ) returns 2.
           column_from_residue_number( "Seq3", 50 ) returns 10.

           An exception is thrown if the residue number would lie
           outside the length of the aligment
           (e.g. column_from_residue_number( "Seq2", 22 )

      	  Note: If the the parent sequence is represented by more than
	        one alignment sequence and the residue number is present in
	        them, this method finds only the first one.

 Returns : A column number for the position in the alignment of the
           given residue in the given sequence (1 = first column)
 Args    : A sequence id/name (not a name/start-end)
           A residue number in the whole sequence (not just that
           segment of it in the alignment)

Sequence names

Methods to manipulate the display name. The default name based on the sequence id and subsequence positions can be overridden in various ways.

displayname

Title     : displayname
Usage     : $myalign->displayname("Ig", "IgA")
Function  : Gets/sets the display name of a sequence in the alignment
Returns   : A display name string
Argument  : name of the sequence
            displayname of the sequence (optional)

set_displayname_count

Title     : set_displayname_count
Usage     : $ali->set_displayname_count
Function  : Sets the names to be name_# where # is the number of
            times this name has been used.
Returns   : 1, on success
Argument  :

set_displayname_flat

Title     : set_displayname_flat
Usage     : $ali->set_displayname_flat()
Function  : Makes all the sequences be displayed as just their name,
            not name/start-end
Returns   : 1
Argument  :

set_displayname_normal

Title     : set_displayname_normal
Usage     : $ali->set_displayname_normal()
Function  : Makes all the sequences be displayed as name/start-end
Returns   : 1, on success
Argument  :

source

Title   : source
Usage   : $obj->source($newval)
Function: sets the Alignment source program
Example :
Returns : value of source
Args    : newvalue (optional)

annotation

Title   : annotation
Usage   : $ann = $aln->annotation or 
          $aln->annotation($ann)
Function: Gets or sets the annotation
Returns : Bio::AnnotationCollectionI object
Args    : None or Bio::AnnotationCollectionI object

See Bio::AnnotationCollectionI and Bio::Annotation::Collection for more information