From David Lynch's Mulholland Drive: Diane Selwyn has a dream in which we see a pool cleaner's pickup truck parked at Adam Kesher's house. The pool-man is inside the home, cheating in bed with Adam's wife. The words 'Gene Clean' painted on the side of the truck refer not only to Gene the pool man in Mulholland Drive, but also, the missing word, 'pool', is a reference to Frank Poole's last name, and ultimately to the idea of cleaning a (human) gene pool, which was effectively what the Nazi's supposedly believed they were doing by attempting to exterminate the Jews just before and during World War II.
Lynch is here giving us a clue about Frank Poole's last name being a reference to the general populace (i.e., 'gene pool'). The clue is also a reference to the situation with the Nazis and Jews, as indicated above, and Lynch believes Kubrick was making some sort of statement on this subject (i.e., the subject of the Jews and Nazis) in A Space Odyssey.
