DNA test for the dilute (dd) locus – It’s here, it can be done!


Just to be sure that I’m not talking about something that doesn’t exist and can’t be done, I approached three veterinary genetic laboratories, yesterday, and asked them if it’s technically possible to specifically test for the dilute (dd) locus in Labrador Retrievers. All three of these laboratories, VetGen, Laboklinet and VHL Genetics (the Van Haeringen Group) responded very quickly, with a positive reply. And if they can do it, others can.

Dear Jack,

We offer the D-locus mutation on the MLPH gene which is the cause for color dilution in dogs. We test it under the internal reference code H815 (http://tinyurl.com/D-locus). In dogs this mutation is also known alopecia (http://omia.angis.org.au/OMIA000031/9615/).

So, to answer your first questions: yes, it is possible to test for this mutations in Labradors.

With regards to making this mutation a standard in Labradors; is not up to us to decide. If a breeder would like to have the mutation tested with every sample he or she will submit, the choice is up to the breeder or the breeding society.

Kind regards,

Maarten de Groot


VetGen replied this:


Yes, we can and have detected the d allele in Labrador Retrievers.  Determining whether such testing becomes standard is not up to us, but rather the owners/breeders/clubs who pay for our services.
We also can detect the two recessive alleles at the K locus (kbr and ky) that lead to tan point and brindle point Labs.  About 1 out of 25-30 Labs carry one or the other of these meaning that between 1 in 625 and 1 in 900 litters will produce pups with tan or brindle points.

And from Vetgen Customer Service:

Hi Jack,

I am including a link to the secure Labrador shopping cart on the VetGen site. Here you will see that the dilution test is offered right along with b, e and k (brindling). Customers may select any or all of what we offer.

http://vetgen.com/ordertests.aspx?id=Labrador Retriever

Thank you and best regards,

VetGen Customer Service

Laboklin (U.K.) answered this:

Dear Mr Vanderwyk,

Thank you for your email.

My answer to your questions: Yes we offer test for the dilute gene and it is valid for all dog breeds including Labrador, it is test number 8136 Dilution or D locus.

As a lab we offer the test to anyone interested. We are not in a position to get involved in breed standards or breeding decisions, it is up to breeders, breeding clubs, and or the breed council to decide whether to recommend this test as a standard test in Labrador.

If you have any further questions please do not hesitate to contact me.

Kind regards

Dr Mansour Makki
Laboratory For Veterinary Diagnostics


P.S. Many of our American friends are testing their dogs with DDC Veterinary. OFA accepts these results.

Now we know that Labradors can be tested for the dilute (d) gene, we have a powerful instrument in our hands to exclude affected dogs and carriers of the dd locus from breeding with dogs from respectable Labrador breeders.

Breeders of “silver”, “champagne” and “charcoal” Labradors will do anything to get well respected Labradors into their mutts’ bloodlines. They might come to visit your stud dog with a carrier of the dilute (d) gene, without mentioning this fact, and the result will be that the name of your Champion Labrador ends up in the pedigree certificates of these mutts. They’re doing it all the time, they’ll try to do it again.
Now you can demand that the owners of a bitch you don’t know produce scientific proof that the bitch doesn’t carry the dilute (d) gene. 

This information opens many doors, and with it we can move on to the next step: to approach the guards of the stud books, usually the national kennel clubs, and force them to do their job: making sure that any Labrador with a pedigree is a purebred Labrador. If they fail to use this instrument, if they fail to see that the dilute (d) locus is alien to the Labrador Retriever, thus that any “Labrador” carrying the dilute (d) locus is NOT A PUREBRED LABRADOR, we need to take them to court.

Jack Vanderwyk,
January 2014

Please sign and share this petition! 


How can you be sure your Labrador is dilute free? By having your dog’s DNA tested on the dilute gene. DD is the only acceptable result.
EEBBDD = Dilute-free black Lab
EEBbDD = Dilute-free black Lab carrying chocolate
EEbbDD = Dilute-free chocolate Lab
EeBBDD = Dilute-free black Lab carrying yellow
EeBbDD = Dilute-free black Lab carrying yellow and chocolate
EebbDD = Dilute-free chocolate Lab, carrying yellow
eeBBDD = Dilute-free yellow Lab with black pigment
eeBbDD = Dilute-free yellow Lab carrying chocolate
eebbDD = Dilute-free yellow Lab with chocolate pigment

If any of the D’s is recessive, it’s not a dilute-free Lab, so not a purebred Lab, as the dilute gene is alien to the Labrador Retriever breed.

EEBBDd = black dilute (charcoal) carrier = not a Lab
EEBBdd = black dilute (charcoal) = not a Lab
EEBbDd = black dilute (charcoal) carrier = not a Lab
EEBbdd = black dilute (charcoal) = not a Lab
EEbbDd = chocolate dilute (silver) carrier = not a Lab
EEbbdd = chocolate dilute (silver) = not a Lab
EeBBDd = black dilute (charcoal) carrier = not a Lab
EeBBdd = black dilute (charcoal) = not a Lab
EeBbDd = black dilute (charcoal) carrier = not a Lab
EeBbdd = black dilute (charcoal) = not a Lab
EebbDd = chocolate dilute (silver) carrier = not a Lab
Eebbdd = chocolate dilute (silver) = not a Lab
eeBBDd = yellow dilute (champagne) carrier = not a Lab
eeBBdd = yellow dilute (champagne) = not a Lab
eeBbDd = yellow dilute (champagne) carrier = not a Lab
eeBbdd = yellow dilute (champagne) = not a Lab
eebbDd = yellow dilute (champagne) carrier = not a Lab
eebbdd = yellow dilute (champagne) = not a Lab



About Jack Vanderwyk

Hey! What am I like! :-)
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