to reverse the bases: 
my %ibase;
$ibase{"A"} = "T";
$ibase{"T"} = "A";
$ibase{"C"} = "G";
$ibase{"G"} = "C";
$ibase{"N"} = "N";
sub seq_inverse
{
    my ($nseq) = @_;
    my @seq = split(m//,$nseq);
    my $lim = @seq;
    my $inv = "";

    $inv .= $ibase{$seq[$lim]} while($lim > 0 and $lim--);

    return $inv;
}

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In reply to Re: Extracting DNA sequences from FASTA files by Anonymous Monk
in thread Extracting DNA sequences from FASTA files by statsman5

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