my $str   =  $Genome;
        my $match = "ATCGACTACGACTCGACT";
        my $len   = length($match);
        
        for my $i ( 0 .. length($str) - $len ) {
            my $s = substr $str, $i, $len;
            my $x = $s ^ $match;
            $x =~ tr/\0//d;    # equal characters xor to \0
          
             print "'$s' at offset $i matched\t".length($x)."\n" unless length($x) > 5;
        }