We appreciate and endorse the idea that additional molecular and phenotypic information on natural canid populations will add to our understanding of gene flow and evolutionary histories of domestic dogs and their wild relatives. However, this information could only expand upon, rather than revise, our primary conclusion that the KB allele has been introduced into wolves from dogs.
Several lines of independent evidence indicate that KB is “older” in dogs than in Arctic wolves and their descendants in Yellowstone National Park. Extended haplotypes associated with KB are much shorter in dogs than in wolves, more point mutations have accumulated in dog KB than in wolf KB chromosomes, and the worldwide distribution patterns for KB are much broader in dogs than in wolves. Had the ky to KB mutation originated in North American eastern wolves, as Rutledge and colleagues speculate, it is difficult to envision how it could have spread so widely among dog breeds around the world. Thus, even if KB was introduced from eastern to western wolves during the Wisconsin glaciation, KB in eastern wolves would still have been acquired originally from American (in this case, Native American) dogs.