[Steuard]

Right, so he's claiming that the genes responsible for this really pretty random list of traits ("protruding, cartilaginous mucous noses"? "Prostate encircles urethra"? "Alcoholism"?) were so strongly selected for that they became 100% ubiquitous in the human genome. Meanwhile, every other trace of pig ancestry got diluted away to nothing.

I understand the idea of dilution, I just don't understand why he thinks that so many random things would survive it to become defining features of the human species. Remember, he's not just saying that 2% of living humans carry Genghis Khan's Y-chromosome or have red hair or something, he's saying that all of these traits became completely universal.