Gene D1746, Chromosome 18, Site forty-two
“They’re an oversight. Some poor designer was too busy thinking about next week’s production quotas, or his digestive troubles, or his unrequited love for whatever norm-conforming certifiably A-Equivalent piece of tail he happened to be chasing at the moment. His mind strayed”–Arkasha’s free hand slid down Arkady’s chest and across his belly–”unforgivably from the all-important work at hand. An error crept into the D1746 gene at site forty-two of chromosome eighteen. That’s the frizzy D site to you and the rest of the hoi polloi. Our poor designer failed to notice the error. It began to replicate. The control team, perhaps similarly distracted by work, lust, or digestion, also failed to notice the error. Which continued to replicate. Which resulted in your spectacular cowlicks. Which resulted in my falling in love with you. Which is about to result in … here, hold this.”
Spin State by Chris Moriarty, p. 286. (emphasis added.)