I’mactually wondering something: a certain friend of mine (and obviously he’s confused here, since his opinion differes from mine 
) says that foxes, coyotes, wolves, and dogs have crosed up genes through interbreeding.
I say: coyotes, wolves, and sometimes dogs yes! Foxes? No! (Probably Hyena’s no, too, but who’se counting?)
What’s the real scoop?
No. As far as l know, all species in the genus Canis (wolves, coyotes, jackals, and domestic dogs) are able to produce fertile hybrids. I have never heard of any of them producing hybrids with foxes (Vulpes and others), which are relatively distantly related within the same family.
It is well established now that the only wild species that has provided any genes to the domestic dog is the Gray or Timber Wolf Canis lupus. It was formerly proposed that there might have been some cross-breeding with jackals involved, but that has been disproved. There certainly hasn’t ever been any crossing with foxes.