D-Locus (Dilute Coat Colour)

The MLPH gene codes for a protein called melanophilin, which is responsible for transporting and fixing melanin-containing cells. A mutation in this gene leads to improper distribution of these cells, causing a dilute coat colour. This mutation is recessive, so two copies of the mutated gene, or "d" allele, are needed to produce the dilute coat colour.

This mutation affects both eumelanin and phaeomelanin pigments, so black, brown, and yellow dogs are all affected by the dilution. A dilute black dog is generally known as "blue," though other names do vary for different breeds, such as charcoal or grey.

Because the mutation responsible for the dilution phenotype is recessive, a dog can be a carrier of the dilution gene and still appear to have a normal coat colour. Such dogs that are carriers of this gene are sometimes referred to as "Silver-Factored", in the case of a black dog carrying the dilution gene. These dogs can pass on either the full-colored or dilute allele to any offspring. This means that two dogs that appear full-coloured can have a dilute puppy. This makes DNA testing for the D-Locus an important breeding tool, whether breeding for a dilute coat, or to avoid it.

Chocolate Dilute Basic Color Description
B/B D/D Black
B/B d/d Blue
b/b D/D Liver/Chocolate
b/b d/d Faded Liver/Chocolate

D Locus Testing:
Animal Genetics currently offers a test for the D-Locus to determine how many copies of the recessive allele a dog carries

Dogs can be DNA tested at ANY age

Sample Type:
Animal Genetics accepts Buccal Swab, Blood, and Dewclaw samples for testing. Sample collection kits are available and can be ordered at Test Now.

Testing is Relevant For The Following Breeds:
All Breeds.

Animal Genetics offers DNA testing for dominant D allele. The genetic test verifies the presence of the mutation and presents results as one of the following:

D/D non-dilute The dog carries two copies of the dominant "D" allele. The dog will express a normal, non-dilute coat colour, and will always pass on a copy of the "D" allele to all offspring.
D/d non-dilute carrier Both the dominant and recessive alleles detected. The dog will have a normal, non-dilute coat, and is a carrier of the dilute coat colour. The dog can pass either allele on to any offspring.
d/d dilute The dog has two copies of the recessive "d" allele, and will have a dilute coloured coat. He will always pass on a copy of the dilute allele on to any offspring.

To Submit a Sample For Testing:
Please download a submission form, or order canine sample collection kits at Test Now.

Mail samples to:
Animal Genetics UK,
PO BOX 107, Truro,
Cornwall, England.
TR1 2YR.

Animal Genetics UK
A-Locus (Fawn/Sable Allele)
A-Locus (Recessive Black Allele)
B-Locus (Black/Brown)
D-Locus (Dilution)
E-Locus (Recessive Yellow Allele)
E-Locus (Melanistic Mask Allele)
Hair Curl
Hair Furnishings
Hair Length
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Pricing: 45.00 per test (inclusive of tax, certification included free of charge)
Turnaround time: 5-7 business days.
Results: Phoned, faxed or e-mailed. Testing certificate dispatched after conclusion of test.