$seq =~ s/\s//g;

##</code><code>##

$seq =~ s/\s+//g;

##</code><code>##

my $A = () = $seq =~ /A/ig;

##</code><code>##

my $A = $seq =~ tr/aA//;

##</code><code>##

my @matches = $seq =~ /[AG]TG.*?T[AG][AG]/ig;
print "Here are the matched parts of the string:\n";
print "  '$_'\n" for @matches;
my $GENE = @matches;