That's not true, though. There's nothing to corrupt. The human genome is 41% fruit fly, 60% banana and 8% virus simultaneously. Hugh Mann Georg, whose genome is 131 billion percent human is an outlier adn should not have been counted.

Plus natural selection isn't solely random by nature, nor is it independent of humans. It doesn't magically go away, even with sci-fi gene technology, since people would naturally select genes that they find attractive, make them superhuman, or won't give them some nasty disease. Humans deciding that they want a gene that gives them breasts all-year round because they find them attractive is no different to humans selecting for the trait over generations, for much the same reason.