How many generations to produce a distinct "line" or "new breed" of animal?

[RyGuyFly]

Any thoughts on how many generations of selective breeding it would require to produce animals significantly different from the general population?

 

Maybe for an example how many generations would be required to produce a pug-faced poodle if you started with regular poodles? I know many of the dog breeds have been "reshaped" over the last 100 years. So that would have to be less than 100 generations I would think.

[John Cuthber]

Few enough that it has been done.

http://blogs.scientificamerican.com/guest-blog/mans-new-best-friend-a-forgotten-russian-experiment-in-fox-domestication/

The report says "over 40 generations".