Trim fasta.pl

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1. ! /usr/bin/perl -w
2. *************************************************************
3. This Programme does the following in sequence
4. -> Parses a multi fasta
5. -> Removes the sequence if they have <50bp and of 'N'
6. -> Capture the results

1. Author : Rajkumar (itc@rajkumar.in)
2. Release: DEC 2009
3. *************************************************************

1. Libraries

use strict; use Bio::Perl; use Bio::SeqIO;

1. Variables

my $path = "/home/raj/bio"; my $multifasta = "$path/euca/data/globulus/globulus_est.fa";

1. making several Fasta files of GDNA

my $in = Bio::SeqIO->new(-file => "$multifasta", -format => 'Fasta'); my $identifier; my $sequence;

while ( my $seq = $in->next_seq() ) { $identifier = $seq->id;

 		$sequence = $seq->seq;

my ($fasta) = $_; $fasta = ">$identifier\n$sequence\n";

my $count_seq = length($sequence); my $count_N = ($sequence =~ tr/N//);

 		my $math = $count_seq * 0.2;
 		

$sequence =~ s/-/N/; if ($count_seq < 50){ next; } if ($count_N > $math){ next; }

print $identifier."\n";

}

1. END

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