Dog breeds

[Karen2005]

Could a Chihuahua sucessfully breed with a Great Dane?

How different would two breeds of dog have to be before they are classified as different species all together?

At what stage would two different pure breeds of dog become a separate species of animal?

[woofgang]

okay, they would never be a different species, but you could evolve a different breed like Louis Dobermann did.

IMO the bred would be "different" once it bred true and no longer needed to be back bred to the breeds used to create it. It would also need to have a large enough gene pool to avoid the problems created by inbreeding, both genetic and those which are hereditary and thus replicated by breeding with affected animals.

if you are talking about biological classifiaction then I guess that today that decision would be made on a basis of DNA.

If you are talking about Kennel Club Registration, I am sure that each country would have its own hoops to jump through.

The mechanical and humane issues of breeding a large and small breed are obvious, it should also be added that it would put both bitch and puppies at risk for the bitch to be from the smaller breed.

Please please reassure me that this question has no practical point?

[Karen2005]

No, this question has absolutely no practical points! Purely academic. I don't own dogs and I have no interest in breeding them!

I'm reading a book about Darwin and evolution at the moment and it got me thinking about breeds of dog and how different they look. I understand that different breeds evolved a bit like species do by combining certain characteristics that are favourable. I guess I thought that given enough time (thousands/millions of years) and some barrier to reproduction then certain breeds of dogs may split sufficiently to become two distinct species.

[Karen2005]

I suppose I might add that given enough time any species may split and evolve different species. Evolution is such a slow process that I guess it's impossible to guess how things will end up in a few thousand years.

[woofgang]

thanks! The answer is already out there....dogs wolves and foxes, lions and tigers....all with differing dna, all with the same (canine or feline) background

[jake-the-peg]

You might like to consider ligers and tions where 2 different species have cross bred

Ligers are impressive things weighing in at 900 pounds and standing 12 feet tall on hind legs

http://en.wikipedia.org/wiki/Liger

All known males have been sterile but not females - so if somebody manages to breed a fertile male you have to ask whether that would proove the generation of a new species or whether you would then say that lions and tigers were the same species "by definition"

[Eels]

Two species are defined as such when they cannot produce fertile offspring when bred together.

For example, a horse can breed with a donkey and produce live offspring, but the resulting mule will be infertile. Thus a horse and a donkey are separate species.

For dogs that day is a long way off - believe it or not, a Great Dane and a Chihuahua are genetically closer than the horse and the donkey are!

[jake-the-peg]

So eels what about lions and tigers then where the male offspring are infertile and the female not?

Maybe we need a new definition!

[nagnag]

I feel sorry for the small dog, imagine being a jack russell mated with a rotweiller. I would imagine the little 'un being eaten after mating.