Bio::SimpleAlign(3pm) | User Contributed Perl Documentation | Bio::SimpleAlign(3pm) |
Bio::SimpleAlign - Multiple alignments held as a set of sequences
# 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->num_residues; print $aln->is_flush; print $aln->num_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); # select certain sequences $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.
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.
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
Please direct usage questions or support issues to the mailing list:
bioperl-l@bioperl.org
rather than to the module maintainer directly. Many experienced and reponsive experts will be able look at the problem and quickly address it. Please include a thorough description of the problem with code and data examples if at all possible.
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:
https://github.com/bioperl/bioperl-live/issues
Ewan Birney, birney@ebi.ac.uk
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 Weigang Qiu, Weigang at GENECTR-HUNTER-CUNY-EDU Hongyu Zhang, forward at hongyu.org Jay Hannah, jay at jays.net Alexandr Bezginov, albezg at gmail.com
Bio::LocatableSeq
The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _
Title : new Usage : my $aln = Bio::SimpleAlign->new(); Function : Creates a new simple align object Returns : Bio::SimpleAlign Args : -source => string representing the source program where this alignment came from -annotation => Bio::AnnotationCollectionI -seq_annotation => Bio::AnnotationCollectionI for sequences (requires -annotation also be set) -seqs => array ref containing Bio::LocatableSeq or Bio::Seq::Meta -consensus => consensus string -consensus_meta => Bio::Seq::Meta object containing consensus met information (kludge)
These methods modify the MSA by adding, removing or shuffling complete sequences.
Title : add_seq Usage : $myalign->add_seq($newseq); $myalign->add_seq(-SEQ=>$newseq, -ORDER=>5); Function : Adds another sequence to the alignment. *Does not* align it - just adds it to the hashes. If -ORDER is specified, the sequence is inserted at the the position spec'd by -ORDER, and existing sequences are pushed down the storage array. Returns : nothing Args : A Bio::LocatableSeq object Positive integer for the sequence position (optional)
See Bio::LocatableSeq for more information
Title : remove_seq Usage : $aln->remove_seq($seq); Function : Removes a single sequence from an alignment Returns : Argument : a Bio::LocatableSeq object
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
Title : sort_alphabetically Usage : $ali->sort_alphabetically Function : Changes the order of the alignment to alphabetical on name followed by numerical by number. Returns : Argument :
Title : sort_by_list Usage : $aln_ordered=$aln->sort_by_list($list_file) Function : Arbitrarily order sequences in an alignment Returns : A new Bio::SimpleAlign object Argument : a file listing sequence names in intended order (one name per line)
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
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 : 1a. if called in a scalar context, a new Bio::SimpleAlign object (all sequences renamed as "ST") 1b. if called in an array context, a new Bio::SimpleAlign object, and a hashref whose keys are sequence types, and whose values are arrayrefs to lists of sequence ids within the corresponding sequence type 2. if $aln->verbose > 0, ST of each sequence is sent to STDERR (in a tabular format) Argument : None
Methods returning one or more sequences objects.
Title : each_seq Usage : foreach $seq ( $align->each_seq() ) Function : Gets a Seq object from the alignment Returns : Seq object Argument :
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 :
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
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 num_sequences() will throw an error. Returns : a Bio::LocatableSeq object Args : positive integer for the sequence position
Title : get_seq_by_id Usage : $seq = $aln->get_seq_by_id($name) # seq named $name Function : Gets a sequence based on its name. Sequences that do not exist will warn and return undef Returns : a Bio::LocatableSeq object Args : string for sequence name
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
The result of these methods are horizontal or vertical subsets of the current MSA.
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 num_sequences() will throw an error. Returns : a Bio::SimpleAlign object Args : positive integer for the first sequence positive integer for the last sequence to include (optional)
Title : select_noncont Usage : # 1st and 3rd sequences, sorted $aln2 = $aln->select_noncont(1, 3) # 1st and 3rd sequences, sorted (same as first) $aln2 = $aln->select_noncont(3, 1) # 1st and 3rd sequences, unsorted $aln2 = $aln->select_noncont('nosort',3, 1) Function : Creates a new alignment from a subset of sequences. Numbering starts from 1. Sequence positions larger than num_sequences() will throw an error. Sorts the order added to new alignment by default, to prevent sorting pass 'nosort' as the first argument in the list. Returns : a Bio::SimpleAlign object Args : array of integers for the sequences. If the string 'nosort' is passed as the first argument, the sequences will not be sorted in the new alignment but will appear in the order listed.
Title : select_noncont_by_name Usage : my $aln2 = $aln->select_noncont_by_name('A123', 'B456'); Function : Creates a new alignment from a subset of sequences which are selected by name (sequence ID). Returns : a Bio::SimpleAlign object Args : array of names (i.e., identifiers) for the sequences.
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)
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
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().
These methods affect characters in all sequences without changing the alignment.
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
Title : map_chars Usage : $ali->map_chars('\.','-') Function : Does a s/$arg1/$arg2/ on the sequences. Useful for gap characters. Note that the first argument is interpreted as a regexp so be careful and escape any wild card characters (e.g. do $ali->map_chars('\.','-') to replace periods with dashes. Returns : 1 on success Argument : A regexp and a string
Title : uppercase() Usage : $ali->uppercase() Function : Sets all the sequences to uppercase Returns : 1 on success Argument :
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 : threshold (optional, defaults to 100) Returns : Hash of strings (cigar lines)
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
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
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
Title : gap_col_matrix() Usage : my $cols = $align->gap_col_matrix() Function : Generates an array where each element in the array is a hash reference with a key of the sequence name and a value of 1 if the sequence has a gap at that column Returns : Reference to an array Args : Optional: gap line character ($aln->gap_char or '-' by default)
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 on success Argument : a match character, optional, defaults to '.'
Title : unmatch() Usage : $ali->unmatch() Function : Undoes the effect of method match. Unsets match_char. Returns : 1 on success Argument : a match character, optional, defaults to '.'
See match and match_char
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 ('').
Title : id Usage : $myalign->id("Ig") Function : Gets/sets the id field of the alignment Returns : An id string Argument : An id string (optional)
Title : accession Usage : $myalign->accession("PF00244") Function : Gets/sets the accession field of the alignment Returns : An acc string Argument : An acc string (optional)
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)
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)
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)
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)
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
These read only methods describe the MSA in various ways.
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
Title : consensus_string Usage : $str = $ali->consensus_string($threshold_percent) Function : Makes a strict consensus Returns : Consensus string Argument : Optional threshold 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%)
Title : consensus_conservation Usage : @conservation = $ali->consensus_conservation(); Function : Conservation (as a percent) of each position of alignment Returns : Array of percentages [0-100]. Gap columns are 0% conserved. Argument :
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
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
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 :
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 :
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 :
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
Title : num_residues Usage : $no = $ali->num_residues Function : number of residues in total in the alignment Returns : integer Argument : Note : replaces no_residues()
Title : num_sequences Usage : $depth = $ali->num_sequences Function : number of sequence in the sequence alignment Returns : integer Argument : none Note : replaces no_sequences()
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.
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
Title : overall_percentage_identity Usage : $id = $align->overall_percentage_identity $id = $align->overall_percentage_identity('short') Function: The function calculates the percentage identity of the conserved columns Returns : The percentage identity of the conserved columns Args : length value to use, optional defaults to alignment length possible values: 'align', 'short', 'long'
The argument values 'short' and 'long' refer to shortest and longest sequence in the alignment. Method modification code by Hongyu Zhang.
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);
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)
Methods to manipulate the display name. The default name based on the sequence id and subsequence positions can be overridden in various ways.
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)
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 :
Title : set_displayname_flat Usage : $ali->set_displayname_flat() Function : Makes all the sequences be displayed as just their name, not name/start-end (NSE) Returns : 1 Argument :
Title : set_displayname_normal Usage : $ali->set_displayname_normal() Function : Makes all the sequences be displayed as name/start-end (NSE) Returns : 1, on success Argument :
Title : source Usage : $obj->source($newval) Function: sets the Alignment source program Example : Returns : value of source Args : newvalue (optional)
Title : set_displayname_safe Usage : ($new_aln, $ref_name)=$ali->set_displayname_safe(4) Function : Assign machine-generated serial names to sequences in input order. Designed to protect names during PHYLIP runs. Assign 10-char string in the form of "S000000001" to "S999999999". Restore the original names using "restore_displayname". Returns : 1. a new $aln with system names; 2. a hash ref for restoring names Argument : Number for id length (default 10)
Title : restore_displayname Usage : $aln_name_restored=$ali->restore_displayname($hash_ref) Function : Restore original sequence names (after running $ali->set_displayname_safe) Returns : a new $aln with names restored. Argument : a hash reference of names from "set_displayname_safe".
Title : sort_by_start Usage : $ali->sort_by_start Function : Changes the order of the alignment to the start position of each subalignment Returns : 1 on success Argument :
Title : bracket_string Usage : my @params = (-refseq => 'testseq', -allele1 => 'allele1', -allele2 => 'allele2', -delimiters => '{}', -separator => '/'); $str = $aln->bracket_string(@params) Function : When supplied with a list of parameters (see below), returns a string in BIC format. This is used for allelic comparisons. Briefly, if either allele contains a base change when compared to the refseq, the base or gap for each allele is represented in brackets in the order present in the 'alleles' parameter. For the following data: >testseq GGATCCATTGCTACT >allele1 GGATCCATTCCTACT >allele2 GGAT--ATTCCTCCT the returned string with parameters 'refseq => testseq' and 'alleles => [qw(allele1 allele2)]' would be: GGAT[C/-][C/-]ATT[C/C]CT[A/C]CT Returns : BIC-formatted string Argument : Required args refseq : string (ID) of the reference sequence used as basis for comparison allele1 : string (ID) of the first allele allele2 : string (ID) of the second allele Optional args delimiters: two symbol string of left and right delimiters. Only the first two symbols are used default = '[]' separator : string used as a separator. Only the first symbol is used default = '/' Throws : On no refseq/alleles, or invalid refseq/alleles.
FeatureHolderI implementation to support labeled character sets like one would get from NEXUS represented data.
Usage : @features = $aln->get_SeqFeatures Function: Get the feature objects held by this feature holder. Example : Returns : an array of Bio::SeqFeatureI implementing objects Args : optional filter coderef, taking a Bio::SeqFeatureI : as argument, returning TRUE if wanted, FALSE if : unwanted
Usage : $aln->add_SeqFeature($subfeat); Function: Adds a SeqFeature into the SeqFeature array. The 'EXPAND' qualifier (see L<Bio::FeatureHolderI>) is supported, but has no effect. Example : Returns : 1 on success Args : a Bio::SeqFeatureI object
Usage : $obj->remove_SeqFeatures Function: Removes all SeqFeatures. If you want to remove only a subset, remove that subset from the returned array, and add back the rest. Returns : The array of Bio::SeqFeatureI features that was deleted from this alignment. Args : none
Title : feature_count Usage : $obj->feature_count() Function: Return the number of SeqFeatures attached to the alignment Returns : integer representing the number of SeqFeatures Args : None
Title : get_all_SeqFeatures Usage : Function: Get all SeqFeatures. Example : Returns : an array of Bio::SeqFeatureI implementing objects Args : none Note : Falls through to Bio::FeatureHolderI implementation.
AnnotatableI implementation to support sequence alignments which contain annotation (NEXUS, Stockholm).
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
Title : mask_columns Usage : $aln2 = $aln->mask_columns(20,30) Function : Masks a slice of the alignment inclusive of start and end columns, and the first column in the alignment is denoted 1. Mask 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 string value use for the mask. Example: $aln2 = $aln->mask_columns(20,30,'?') Note : Masking must use a character that is not used for gaps or frameshifts. These can be adjusted using the relevant global variables, but be aware these may be (uncontrollably) modified elsewhere within BioPerl (see bug 2715)
2020-10-28 | perl v5.30.3 |