We've had both our dogs DNA tested -- purely for our own entertainment, not because we have any concern about "pure breeding" -- and both of them gave us results that were quite a shock.
First, there's Guinness, whom the rescue agency told us was a black lab/akita mix. You can see why:
Then there's Rosie, who we thought sure would turn out to be fox terrier/beagle:
I'm not sure that it's reasonable to expect a fifty-dollar mail-order dog DNA test to be all that reliable, mind you. In Guinness's case, though, there are features that do make sense -- the ebullient disposition and square face of the AmStaff, and the curly tail and thick, silky undercoat of his husky/chow ancestry. Whatever its accuracy, though, it's fascinating that any signal of ancestry at all shows up in a simple saliva test.
Especially given that just about every dog breed in existence traces back to wild dog populations in only a few thousand years. That's an extremely short time to have any evolutionary divergence take place. But genetic testing has become sophisticated enough that we can now retrace the steps in dog evolution -- creating a family tree of dog relationships encompassing 321 different dog breeds (including several sorts of wild dogs).
A team of geneticists led by Jeff Kidd of the University of Michigan, Jennifer R. S. Meadows of Uppsala University, and Elaine A. Ostrander of the NIH National Human Genome Research Institute did a detailed study of two thousand different DNA samples containing over forty-eight million analyzable sequences. They identified three million SNPs -- single nucleotide polymorphisms, or "snips" -- that were characteristic of certain breeds."We did an analysis to see how similar the dogs were to each other," Kidd said. "It ended up that we could divide them into around twenty-five major groups that pretty much match up with what people would have expected based on breed origin, the dogs' type, size and coloration."