my %count;
$count{substr($genome, $_, 2)}++ for 0..length($genome)-2;
# Next combine the counts like in the original code
# is this a bug or intentional ?
$count{tt} += $count{aa};
$count{ag} += $count{ct};
$count{ac} += $count{gt};
$count{tg} += $count{ca};
$count{ga} += $count{tc};
$count{cc} += $count{gg};