[pstinard]

Originally Posted by pstinard

Hi, I'll park some links here so people can read up on this. If any of these are behind firewalls, I'll quote the relevant parts later. Cross breeding might be fine for a breed of dog in which ALL individuals are affected by a genetic disease, but there are still plenty of healthy breed standard Yorkshire Terriers. The people doing cross breeding with Yorkies are doing so in order to breed in "lovely" coat colors.

Mutations in the SLC2A9 Gene Cause Hyperuricosuria and Hyperuricemia in the Dog

About The Dalmatian Heritage Project - Dalmatian Puppy Breeding & Adoption - Hayward, California

Exclusion of Urate Oxidase as a Candidate Gene for Hyperuricosuria in the Dalmatian Dog Using an Interbreed Backcross

A Dalmatian Study—The Genetic Correction of Health Problems By Robert H. Schaible, Ph.D.

From what I gathered in a quick glance at the Dalmation Heritage Project, a Dalmation was crossed to a healthy Pointer, and then backcrossed to purebred Dalmations for 10 generations, selecting the healthy Dalmations each generation. They are still maintaining the gene in the heterozygous (carrier) state, because they are afraid that with such a low amount of diversity from doing this kind of breeding, the gene pool would be too small if they started creating homozygous healthy Dalmations.

Now, if they're being this careful and ethical with Dalmations, imagine how unethical the breeders are who are crossing other breeds to Yorkies for only three generations and then creating homozygous chocolate, parti, or gold dust Yorkies.