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Description
 MC1R,
also known as the extension gene, controls production of pigment
in melanocytes. The dominant form of the gene, the "E"
allele, allows the dog to produce eumelanin, which is a black pigment.
A mutation in the MC1R gene causes the pigment-producing
cells to only produce phaeomelanin, which is a yellow pigment. This
form of the gene is represented as the "e" allele. The
"e" allele is recessive, meaning that a dog must have
two copies of the MC1R mutation to express the solid yellow coat
color.
A third allele exists in the extension gene,
"EM" which is also dominant. This causes the dog to have
a black mask on their face, also known as a melanistic mask. This
allele acts similarly to the "E" allele, in that it causes
a black-based coat. Because it is dominant, a dog only needs one
copy of the "EM" allele to express this trait. In solid
black dogs with a copy of the "EM" allele, the mask is
hidden, however, it can still pass on the melanistic mask to future
offspring.
The "ee" genotype can vary in expression
between different breeds. In some breeds, the difference between
a black or brown dog and a yellow dog is obvious, such as in Labrador
Retrievers. However, in other breeds, such as Cocker Spaniels, this
difference may be more subtle. Other breeds express the "ee"
phenotype as a red color.
It is important to note that the Extension gene
is only one of 4 important genes in determining the coat color of
a canine. The dogs color can vary greatly with different alleles
at other gene. Dogs that are "ee" will always be yellow,
however, there is a great deal of variation of dogs that are "EE"
or "Ee", depending on the B-Locus, A-Locus, and K-Locus.
E
Locus Testing
The
MC1R gene, or E Locus, has three possible forms Black (E),
melanistic mask (EM), and Yellow (ee). The E-Allele
test determines how many copies of the recessive "e" alleles
a dog carries. The EM-Allele test determines how many copies of
the Melanistic Mask allele a dog carries.
Cost
$40.00
US for the E-allele test.
$40.00 US for the EM-allele test.
$65.00 US combination rate for
both tests.
Sample Collection
Collect
sample using buccal swabs provided by Animal Genetics. Ensure that
the dog has not eaten within a few hours of sample collection. Any
food particles can inhibit the test. Rub each of the swabs along
the inside of the dog's mouth for 10-15 seconds, and allow the swabs
to dry thoroughly. Label the provided envelope with the dog's name,
and place the swab inside it. Download and complete a submission
form for each sample and send along with payment to Animal Genetics
for testing.
Results
Results are given using
the following symbolic notation:
E-Allele Results:
|
E/E
|
The
dog carries two copies of the dominant E allele. The dog will
have a black-based coat, and will always pass on the "E"
allele to any potential offspring. |
|
E/e
|
Both
the dominant and recessive copies of the E allele are present.
The dog will have a black-based coat, but carries the allele
responsible for the yellow phenotype. The dog can pass on either
allele to potential offspring. |
|
e/e
|
Two
copies of the recessive allele are present. The dog has a yellow
coat, and will always pass on the recessive allele to all potential
offspring. |
EM-Allele Results:
|
EM/EM
|
The
dog carries two copies of the melanistic mask allele. The dog
has a melanistic mask, and will always pass on a copy of the
EM allele to potential offspring. All offspring will also have
a melanistic mask. |
|
EM/n
|
One
copy of the melanistic mask allele is present, and the dog will
have a black mask. The dog has a 50% chance of passing on this
allele to potential offspring. |
|
n/n
|
Dog
tested negative for the melanistic mask allele. The dog will
not have a black mask, and cannot pass a copy on to any offspring. |
Combination Test Results:
|
EM/EM
|
The
dog carries two copies of the melanistic mask allele. The dog
has a black-based coat and a melanistic mask, and will always
pass on a copy of the EM allele to potential offspring. All
offspring will also have a melanistic mask. |
|
EM/E
|
One
copy of the melanistic mask allele is present. The dog has a
black-based coat with a black mask. The dog has a 50% chance
of passing on the mask allele to potential offspring. |
|
E/E
|
The
dog carries two copies of the dominant E allele. The dog will
have a black-based coat, and will always pass on the "E"
allele to any potential offspring. No masking is present. |
|
EM/e
|
The dog has
one copy of the melantistic mask allele. The dog's coat is black
based, and he will have a mask on his face. There is a 50% chance
he will pass on either the yellow allele, or the mask allele
on to future offspring. |
|
E/e
|
Both
the dominant and recessive copies of the E allele are present.
The dog will have a black-based coat with no masking, but carries
the allele responsible for the yellow phenotype. The dog can
pass on either allele to potential offspring. |
|
e/e
|
Two
copies of the recessive allele are present. The dog has a yellow
coat, and will always pass on the recessive allele to all potential
offspring. No mask is present. |
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