Zombie Best Friends

Starchy diet may have transformed wolves to dogs

Canine cousins differ in genes related to digestion

Tamed fox shows domestication's effects on the brain

In a different sort of analysis, Pipes discovered that all aggressive foxes carry one form of the GRM3 glutamate receptor gene, while a majority of the friendly foxes have a different variant of the gene. In people, genetic variants of GRM3 have been linked to schizophrenia, bipolar disorder and other mood disorders. Other genes involved in transmitting glutamate signals, which help regulate mood, had increased activity in tame foxes, Pipes said.