Hmm, that meme is different than the image I found associated with the original address. Just for interest, here's the one I found:

As for McCarthy's idea, despite the fact that he's a geneticist, he's apparently been unable to produce any genetic evidence supporting it. Instead he relies exclusively on morphological similarities between pigs and humans, i.e. some physical characteristics are shared by humans and pigs. He claims that the reason there's no genetic evidence is because "humans are probably the result of multiple generations of backcrossing to chimpanzees, which in nucleotide sequence data comparisons would effectively mask any contribution from pig" (
source). His, eh, outré hypothesis hasn't got any traction with scientists who study human origins, as
Pasta Chick said (though not in so many words

).