If a group started with 100,00 pugs could they selectively breed a wolf? How long would it take? Starting with 100,000 wolves how long would it take to breed a pug?
You could never breed back to a wolf from pugs, because pugs as a breed are inbred and have lost many of the alleles that would give wolf characteristics.
If you had a greater range of breeds to work with with more genetic diversity you might eventually arrive at something that looked like a wolf, but it would not be genetically equivalent.
It would take an indefinite time to breed pugs from wolves, since some of the pug’s characteristics are due to mutations, and there’s no telling when equivalent mutations would occur in the population.
However, I think that the ‘yaller dog’ type is easier to breed back to, since it seems to be the prototype domestic dog. Look at pictures of ‘town’ or feral-type dogs hanging around in any town, anywhere in the world. They may not be yellow, although yellow seems to predominate, but they’re all a certain type - medium sized, lean, with long tails and typically long faces.
Well, I have two pugs here. I’ll tell 'em to get going.
Well, technically, you could breed back from a pug to a wolf. Evolution, after all, eventually managed to produce wolves from DNA that had none of the necessary alleles. However, I doubt that you have millions of years to spend breeding canines, and even then, you’d sooner win the lottery than stumble upon the proper sequence of mutations to match an existing species.
You mean a dingo, basically. I don’t know if it’s accepted as more than a theory but I’ve read that if dogs were allowed to interbreed amongst themselves with no outside intervention, something looking very much like a dingo would be the end result.
True. I should perhaps have qualified my answer a little more. But as you say, it’s going to take a very long time to accumulate all the back mutations you would need to reconstitute a wolf, and whatever you get is never going to be genetically exactly the same as a real wolf.
In my Staff Report on the origins of domestic cattle, What did cows evolve from?, I mention attempts to “breed back” to the extinct ancestral form, the Aurochs. Although these animals look a lot like an Aurochs, they are much smaller, and are undoubtedly different genetically.
That’s no theory - it’s an observed fact; how do you think we got dingos in the first place? 
This site has many links on dog ancestry. Many researchers believe that the ancestral dog looked much like the “Yaller Dog,” which resembles dogs believed to be “primitive,” including the dingo, pariah dogs, the New Guinea Singing Dog, Basenjis, Carolina Dog, etc.
Recent genetic evidence indicates that dogs may have developed from wolves more than 100,000 years ago. This conflicts with archeological evidence, in which morphologically distinct dogs first appear perhaps 14,000 years ago.
In that instance. A different population might breed a different result or so I would assume.
IIRC, there aren’t too many known archaeological sites with human remains between 15k and 100k years ago, especially >25k. Presumably, more sites will be found as time goes on, and techniques both for locating sites and for examining them improve. As that happens, we’ll have more information to go on. Maybe we’ll have physical evidence of earlier canid domestication … and maybe not.
In general, I prefer to put more faith in actual remains and artifacts than in genetic evidence. There have been some instances in the last few years when geneticists have made assertions that I find implausible. OTOH, some of their work is based on concepts that are pretty important to the entire structure of biology.
In any case, I do tend to think that dogs go back much farther as domestic animals than any other animals. Until there’s more physical evidence, I prefer to believe that the jury is still out.
Dude. Seriously. From this, to a wolf?
(That’s our pug, Jasmine, a.k.a. The Jazmanian Devil. Quite the terror, isn’t she?)
The interesting (if unsurprising to the initiated) part of this thread is the concealed assumption that pugs represent the ultimate in terms of canine evolution.
I simply don’t understand why other dog breeders haven’t just given up now perfection exists in the form of pugs.
Well, can you think of a dog more unlike a wolf than a pug? I mean, really! I love them to little pieces, but they’re the most unwolfy dog in existance. At least poodles have a yap. Pugs just sort of cough gruffly. And snore.
I beg to differ. Edith has quite the bark. She lets me know everytime that pesky Mr. Athena goes into the garage, or comes in from the garage, or leaves his office, or talks on the phone. She’s also quite the guard dog, if your definition of “guard dog” is “one who barks after someone knocks on the door or rings the doorbell.”
Preach it, brother.
Anyway, it’s been 4 days, and no wolves yet. That might be Frodo’s doing; at only 8 weeks old, he’s not much of a breeder. Then again, Edith is spayed, so she’s not exactly the mothery type. I’ll still keep an eye on them, just in case.
That’s so cute! All my pugs tried really, really hard to be good watchdogs, but there was just too much interesting stuff going on in the kitchen! And they all had the same little gruff “bark” that sounded like a 89 year old emphysema patient off the ventilator.
I love the name Edith. I always had males, and they demanded tough-guy names, even though they could never live up to them. I had a Butch, and Andy and a Rocky (of course).
Butch was so well-trained that one night after a party, we woke up to find him sitting on a pillow in front of the couch. His flat little chin was resting on a plate of cheese and sausage that had been left on the couch cushion. He hadn’t eaten a bite, nor jumped up on the couch. But OH! The pathetic look he gave me. (I gave him some, of course, 'cause he had earned it at that point.) He was far and away the smartest and most trainable dog I’ve owned, of any breed.
I miss my pugs. 
Edith is named after Edith Wharton
The new guy is Frodo, but we considered Rocky.
That story about Butch is amazing! I love my pugs, but have no illusions that they’re trained that well!
And howl. At least, ours does, and it’s the most awful sound; the first time I heard it, I thought she was in pain. It honestly sounds like someone’s torturing her.
Really, though, she just does it when she misses us. Which leads to a lot of, “PUG! I was just in the garage! Chill!”-type statements.
Actually, there are populations of dogs like dingos and the Carolina “yaller dog” all over the world - anywhere where a population has all of the bred traits cancelled. Here’s an article from the Smithsonian: http://www.carolinadogs.org/smith.html
We saw dogs that looked much like dingoes, but with shorter hair, when we were in Bali a few years ago. They’re everywhere. Some of the smartest dang dogs I’ve ever seen, too. They look both ways before crossing streets and herd small children away from cars, although they (the dogs, not the children) don’t appear to “belong” to anybody.
I would assume that dogs on an island are dealing with a pretty limited gene pool, yet they’ve bred themselves back to dingoes.