[pstinard]

Here is a copy of an email that I sent to Animal Genetics, Incorporated, the company that tests for "D Locus" (color dilution) mutations in dogs. I'll let you know if I hear anything back:

"Dear Sirs,

I am writing to inquire about your DNA testing for the "D Locus" in dogs. I am a geneticist by profession, and I have friends who are Yorkshire Terrier breeders, so they wanted me to ask some questions about the test. One of the breeders just produced a litter with a "Blue Yorkie," and they are concerned about its health prognosis, and also want to eliminate the trait from their breeding stock.

First of all, does your test detect the allele responsible for the production of "Blue Yorkies" that have Color Dilution Alopecia? Can you test the DNA of a Blue Yorkie and determine whether it is homozygous for the mutation causing Color Dilution Alopecia? Do your tests also detect whether a Yorkshire Terrier used as breeding stock is a carrier of the mutation causing Color Dilution Alopecia?

Finally, even if your tests can't reveal anything about Color Dilution Alopecia in Yorkshire Terriers, are they accurate enough to detect carriers for the D locus mutations that are responsible for the coat color of Blue Yorkies? I just want to be sure before recommending that they spend money on genetic testing of their breeding stock.

The reason I'm asking is that I've done literature searches, and the most recent articles that I could access weren't 100% certain whether Color Dilution Alopecia is caused by mutations at the MLPH locus, or whether it is due to other factors that are either linked to the MLPH locus, or which interact with it. If you have citations of recent papers that discuss this issue, I'd appreciate it if you could give them to me. I have access to many journals at the University of Illinois, and I can find, read, and understand any articles that you can point me to. Thanks!

Sincerely,

Phil Stinard"