Directly, or through several generations? I.e., could the cross-breed great-grandson of a Great Dane successfully mate with a teacup poodle? Undoubtedly Yes -- which suggests (to me) that they're still the same species.
Also, Chihuahuas can still mate with other small dog breeds, can't they?
Also, what would become of Chihuahuas and Great Danes if we stopped selective breeding? Wouldn't the extremes of dogkind fade over time?
BTW, I want to add my voice to those who have praised these posts for being free of name calling! And Stremba, if you read this, please don't take my occasional stubbornness for disrespect! :-)
...and if pigs had wings, they could fly. What if the cross-breeding was intended to produce a near-microscopic dog and a horse size Great Dane, and the program was kept up for 10,000 years?
Undoubtedly Yes -- which suggests (to me) that they're still the same species.
This is not in the least "undoubted". If insisting on filling the fossil gaps is sauce for the goose, it is sauce for the gander. There were once Marsupial wolves in Australia--do you think they could have been mated with timberwolves because they were about the same size?
Do you think horses, zebras and Donkeys are the same species because they can produce offspring when they mate? If you think they are really one species, how do you think they are going to be merging back together, since their mutual offspring are sterile?
What is your definition of "species"?
Also, is "species" an attribute of an individual entity?