1. –“Since those wolves became dogs more than 15,000 years ago, no new wolf DNA has entered dog genomes. Humans crossbred dogs and wolves, but none of the wolf DNA survived in dogs at large. Modern wolves, however, do show the incorporation of some dog DNA.”—Reich

  2. —“pigs were brought to Europe by farmers from Anatolia. But the genes of those first domesticated pigs have been completely lost, replaced by the genes of wild European boars, even though the pigs stayed domesticated animals.”—Reich

  3. The answer, of course, is that we culled aggression from dogs by preventing their breeding (or worse). We HAVEN”T culled aggression from all humans. That’s what the data says.