Canine Coat Colours

Dogs display a wide variety of coat colours and patterns. Classification of these colours can be confusing sometimes because different registries or associations may use different names for the same colour. In each dog two pigments are the basis for their coat colour: black pigment (eumelanin) and red/yellow/cream pigment (pheomelanin). The production of black and red/yellow/cream pigment is controlled by the Melanocortin 1 Receptor (MC1R) gene, also known as Extension gene or E-Locus. Several other genes are involved that modify the black and red/yellow/cream pigment resulting in a variety of colours and patterns found in the domestic dog. The Tyrosinase-Related Protein 1 (TYRP1) gene, also known as Brown gene or B-Locus dilutes black pigment to brown but does not have an effect on red/yellow/cream pigment. Another gene involved in the coat colour of dogs is the Agouti (ASIP), also known as A-Locus, which controls the distribution of black and red/yellow/cream pigment. The Dilute (MLPH) gene, also known as D-Locus dilutes the black and red/yellow/cream pigment. The Beta-defensin (CBD-103), also known as K-Locus is unique to dogs and is responsible for dominant black. Some other genes that add white patterns and dilute colours are also present but are specific to certain breeds.

Within the above described coat colour genes, three genes explain the major differences; the E-, B-, and D-Locus genes. In the table below the possible combinations of the genes are indicated.

E-Locus

B-Locus

D-Locus

Coat Colour

Nose/foot pads

e/e

B/B

D/D or D/d

Red/Yellow/Cream

Black

e/e

B/B

d/d

Champagne

Blue to Black

e/e

B/b

D/D or D/d

Red/Yellow/Cream (carrierblack/brown/chocolate/liver)

Black

e/e

B/b

d/d

Champagne (carrierblack/brown/chocolate/liver)

Blue to Black

e/e

b/b

D/D or D/d

Red/Yellow/Cream (carrierblack/brown/chocolate/liver)

Pink to Brown

e/e

b/b

d/d

Champagne (carrierblack/brown/chocolate/liver)

Pink to Brown

E/e

B/B

D/D or D/d

Black, no melanistic mask (carrier red/yellow/cream)

Black

E/e

B/B

d/d

Blue/Grey/Charcoal, no melanistic mask (carrier red/yellow/cream)

Blue to Black

E/e

B/b

D/D or D/d

Black, no melanistic mask

(carrierblack/brown/chocolate/liver and carrier red/yellow/cream)

Black

E/e

B/b

d/d

Blue/Grey/Charcoal, no melanistic mask

(carrierblack/brown/chocolate/liver and carrier red/yellow/cream)

Blue to Black

E/e

b/b

D/D or D/d

Brown/chocolate/liver, no melanistic mask (carrier red/yellow/cream)

Pink to Brown

E/e

b/b

d/d

Lilac/Light tan/Isabela, no melanistic mask

(carrierblack/brown/chocolate/liver and carrier red/yellow/cream)

Pink to Brown

Em/e

B/B

D/D or D/d

Black, melanistic mask is not visible (carrier red/yellow/cream)

Black

Em/e

B/B

d/d

Blue/Grey/Charcoal, melanistic mask is not visible

(carrier red/yellow/cream)

Blue to Black

Em/e

B/b

D/D or D/d

Black, melanistic mask is not visible

(carrierblack/brown/chocolate/liver and carrier red/yellow/cream)

Black

Em/e

B/b

d/d

Blue/Grey/Charcoal, melanistic mask is not visible

(carrierblack/brown/chocolate/liver and carrier red/yellow/cream)

Blue to Black

Em/e

b/b

D/D or D/d

Brown/chocolate/liver, with melanistic mask (carrier red/yellow/cream)

Pink to Brown

Em/e

b/b

d/d

Lilac/Light tan/Isabela, with melanistic mask

(carrierblack/brown/chocolate/liver and carrier red/yellow/cream)

Pink to Brown

E/E

B/B

D/D or D/d

Black, no melanistic mask

Black

E/E

B/B

d/d

Blue/Grey/Charcoal, no melanistic mask

Blue to Black

E/E

B/b

D/D or D/d

Black, no melanistic mask (carrierblack/brown/chocolate/liver)

Black

E/E

B/b

d/d

Blue/Grey/Charcoal, no melanistic mask

(carrierblack/brown/chocolate/liver)

Blue to Black

E/E

b/b

D/D or D/d

Brown/chocolate/liver, no melanistic mask

Pink to Brown

E/E

b/b

d/d

Lilac/Light tan/Isabela, no melanistic mask

(carrierblack/brown/chocolate/liver)

Pink to Brown

Em/E

B/B

D/D or D/d

Black, melanistic mask is not visible

Black

Em/E

B/B

d/d

Blue/Grey/Charcoal, melanistic mask is not visible

Blue to Black

Em/E

B/b

D/D or D/d

Black, melanistic mask is not visible

(carrierblack/brown/chocolate/liver)

Black

Em/E

B/b

d/d

Blue/Grey/Charcoal, melanistic mask is not visible

(carrierblack/brown/chocolate/liver)

Blue to Black

Em/E

b/b

D/D or D/d

Brown/chocolate/liver, with melanistic mask

Pink to Brown

Em/E

b/b

d/d

Lilac/Light tan/Isabela, with melanistic mask

(carrierblack/brown/chocolate/liver)

Pink to Brown

Em/Em

B/B

D/D or D/d

Black, melanistic mask is not visible

Black

Em/Em

B/B

d/d

Blue/Grey/Charcoal, melanistic mask is not visible

Blue to Black

Em/Em

B/b

D/D or D/d

Black, melanistic mask is not visible

(carrierblack/brown/chocolate/liver)

Black

Em/Em

B/b

d/d

Blue/Grey/Charcoal, melanistic mask is not visible

(carrierblack/brown/chocolate/liver)

Blue to Black

Em/Em

b/b

D/D or D/d

Brown/chocolate/liver, with melanistic mask

Pink to Brown

Em/Em

b/b

d/d

Lilac/Light tan/Isabela, with melanistic mask

(carrierblack/brown/chocolate/liver)

Pink to Brown

* Three variants (bs,bc and bd ) of the b-allele are known. Since all three variants result in the same effect, in the above scheme all variants are named b.

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COAT COLOURS:

E-Locus: H734 Coat Colour E-Locus and H818 Coat Colour Em-Locus

In each dog two pigments are the basis for their coat colour: black pigment (eumelanin) and red/yellow/cream pigment (pheomelanin). The production of black and red/yellow/cream pigment is controlled by the Melanocortin 1 Receptor (MC1R) gene, also known as Extension gene or E-Locus. The Coat Colour E-Locus (H734) and Coat Colour Em-Locus (H818) combined reveal the genetic status of the E-Locus. The E-Locus has three variants (alleles). The Em allele is dominant over the alleles E and e; allele E is dominant over allele e. The dominant allele Em causes a melanistic face mask. Dogs that are solid black may have the allele Em but the mask is not visible as it is indistinguishable from the body colour. Dogs with white muzzles may have the allele Em but the mask is overridden by white spotting patterns. The Melanistic face mask is present in a variety of breeds (e.g. Afghans, Akitas, Boxers, French Bulldogs, German Shepherds, Great Danes, Greyhounds, Pug Dogs and Whippets). Pug Dogs and Boxers are fixed for the Em allele. The allele E results in a black coat colour and the allele e results in a red coat colour. In Afghan and Saluki hounds a fourth allele has been identified which only is expressed when the dominant black (K-Locus) is not present and the A-Locus is at/at. This fourth allele Eg causes a pattern that is called grizzle or domino. VHLGenetics does not offer a test that detects the Eg allele.

The Coat Colour E-Locus and Coat Colour Em-Locus tests (together E-Locus) enclose the following results, in this scheme the results of the E-Locus are shown in combination with the possible results for the B-Locus:

E-Locus

Em-Locus

E-Locus (complete)

B-Locus*

Coat Colour

E/E

Em/Em

Em/Em

B/B or B/b

b/b

Black, melanistic mask is not visible

Brown/chocolate/liver, with melanistic mask

E/E

Em/N

Em/E

B/B or B/b

b/b

Black, melanistic mask is not visible

Brown/chocolate/liver, with melanistic mask

E/e

Em/N

Em/e

B/B or B/b

b/b

Black, melanistic mask is not visible

Brown/chocolate/liver, with melanistic mask

E/E

N/N

E/E

B/B or B/b

b/b

Black, no melanistic mask

Brown/chocolate/liver, no melanistic mask

E/e

N/N

E/e

B/B or B/b

b/b

Black, no melanistic mask

Brown/chocolate/liver, no melanistic mask

e/e

N/N

e/e

B/B, B/b or b/b

Red/Yellow/Cream

* Three variants (bs,bc and bd ) of the b-allele are known. Since all three variants result in the same effect, in the above scheme all variants are named b. (B/bc, B/bd and B/bs are in the above scheme B/b. bc/bc, bc/bd/bd/bd, bs/bc, bs/bd and bs/bs are in the above scheme b/b). More explanation about the result > 2b please is available under B-Locus: H733 Coat Colour B-Locus.

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B-Locus: H733 Coat Colour B-Locus

The Tyrosinase-Related Protein 1 (TYRP1) gene, also known as Brown gene or B-Locus controls the dilution from black pigment to brown. The TYRP1 gene has no effect on the hair colour of dogs that are homozygous ee for the E-Locus as they do not have black pigment, but does have an effect on the colour of the nose and foot pads of these dogs. The Coat Colour B-Locus (H733) tests for the genetic status of the B-Locus. The B-Locus has four variants (alleles). The B allele is dominant and does not dilute the black pigment. From the recessive b allele three variants exist bs, bd and bc. All three variants of the recessive b allele have the same effect resulting in dilution of the black pigment into brown/chocolate/liver. Only when the dog has two copies of the recessive allele b (homozygous bb) the black pigment will be diluted to brown/chocolate/liver. For dogs that are red/yellow/cream and carry two copies of the recessive allele b the hair colour is not diluted but the colour of the nose and foot pads is changed from black to brown. In some breeds other mutations are present that cause chocolate colour that have not been identified yet. For example, the mutation for chocolate in French Bulldogs has not been found yet and the genetic basis is not known at this time

The Coat Colour B-Locus test encloses the following results, in this scheme the results of the Coat Colour B-Locus test are shown in combination with the possible results for the E-Locus):

B-Locus

E-Locus

Coat Colour

Nose/foot pads

B/B

Em/Em, Em/E or Em/e

Black, melanistic mask is not visible

Black

B/B

E/E or E/e

Black, no melanistic mask

Black

B/B

e/e

Red/Yellow/Cream

Black

B/b*

Em/Em, Em/E or Em/e

Black, melanistic mask is not visible

Black

B/b*

E/E or E/e

Black, no melanistic mask

Black

B/b*

e/e

Red/Yellow/Cream

Black

b/b*

Em/Em, Em/E or Em/e

Brown/chocolate/liver, with melanistic mask

Brown

b/b*

E/E or E/e

Brown/chocolate/liver, no melanistic mask

Brown

b/b*

e/e

Red/Yellow/Cream

Brown

> 2b

This dog carries more than two b-alleles. The colour of this dog can be brown or black.

Option 1: The dog is black. In this case it also carries one copy of the B-allele.

Option 2: The dog is brown. In this case it carries only b-alleles.

* Three variants (bs,bc and bd ) of the b-allele are known. Since all three variants result in the same effect, in the above scheme all variants are named b. (B/bc, B/bd and B/bs are in the above scheme B/b. bc/bc, bc/bd/bd/bd, bs/bc, bs/bd and bs/bs are in the above scheme b/b).

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D-Locus: H847 Coat colour D-Locus Improved (MLPH)

The dilute gene (MLPH gene) is responsible for the intensity of the coat colour by affecting the distribution of melanin-containing cells. This gene is also known as the D-Locus and dilutes all colours. Besides the hair colour also the colour of the nose is diluted and the colour of the eyes lightens to amber. The Coat Colour D-Locus Improved (MLPH) test (H847) tests for the genetic status of the D-Locus. The D-Locus has two variants (alleles). The allele D is dominant and does not have an effect on the coat colour. Only when the dog has two copies of the recessive allele d the coat colour is diluted. The dilution of black results in grey, also called blue or charcoal. The coat ranges from silver to almost black, but all have a blue nose. Chocolate/brown/liver dilutes into lilac/light tan/Isabella, their noses vary from pink, liver to isabella. Red/yellow/cream dilutes into champagne. In some breeds another, yet unidentified, mutation is present that causes coat colour dilution. This unidentified mutation is known to occur in Doberman Pinscher, French Bulldog, Italian Greyhound, Chow Chow and Shar-Pei.

The Coat Colour D-Locus Improved (MLPH) test encloses the following results, in this scheme the results of the Coat Colour D-Locus Improved (MLPH) test are shown in combination with the possible results for the E-Locus and B-Locus):

D-Locus

E-Locus

B-Locus

Coat Colour

Nose/foot pads

D/D

Em/Em, Em/E or Em/e

B/B or B/b

Black, melanistic mask is not visible

Black

D/D

Em/Em, Em/E or Em/e

b/b

Brown/chocolate/liver, with melanistic mask

Pink to Brown

D/D

E/E or E/e

B/B,B/b

Black, no melanistic mask

Black

D/D

E/E or E/e

b/b

Brown/chocolate/liver, no melanistic mask

Pink to Brown

D/D

e/e

B/B,B/b

Red/Yellow/Cream

Black

D/D

e/e

b/b

Red/Yellow/Cream

Pink to Brown

D/d

Em/Em, Em/E or Em/e

B/B or B/b

Black, melanistic mask is not visible

Black

D/d

Em/Em, Em/E or Em/e

b/b

Brown/chocolate/liver, with melanistic mask

Pink to Brown

D/d

E/E or E/e

B/B,B/b

Black, no melanistic mask

Black

D/d

E/E or E/e

b/b

Brown/chocolate/liver, no melanistic mask

Pink to Brown

D/d

e/e

B/B,B/b

Red/Yellow/Cream

Black

D/d

e/e

b/b

Red/Yellow/Cream

Pink to Brown

d/d

Em/Em, Em/E or Em/e

B/B or B/b

Blue/Grey/Charcoal, melanistic mask is not visible

Blue to Black

d/d

Em/Em, Em/E or Em/e

b/b

Lilac/Light tan/Isabela, with melanistic mask

Pink to Brown

d/d

E/E or E/e

B/B,B/b

Blue/Grey/Charcoal, no melanistic mask

Blue to Black

d/d

E/E or E/e

b/b

Lilac/Light tan/Isabela, no melanistic mask

Pink to Brown

d/d

e/e

B/B,B/b

Champagne

Blue to Black

d/d

e/e

b/b

Champagne

Pink to Brown

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A-Locus: H820 Coat Colour A-Locus

The Agouti gene (ASIP gene) is responsible for the production of a protein that regulates the distribution of black pigment (eumelanin) within the hair shaft. This gene is also known as the A-locus and determines whether an animal expresses an agouti appearance, and if so what type, by controlling the distribution of pigment in individual hairs. The agouti pattern can be seen in both black-based and red-based colours. The coat colour is further complicated by the interaction with the K-locus and the E-locus. The agouti pattern is only expressed if on the K-locus no copy of the KB allele is present in combination with at least one copy of the E or Em allele on the E-locus. The Coat Colour A-Locus test (H820) tests for the genetic status of the A-locus. The A-locus has four variants (alleles). The most dominant allele is Ay, followed by aw, then at, then a. The dominant Ay allele produces a sable or fawn coat colour. The allele aw produces a colour known as wild sable or wild type. With this colouration, the hairs switch pigmentation from black to reddish or fawn. This colour is sometimes seen in German Shepherds and other shepherd breeds. The allele at results in tan points (tan markings on a dark dog) and produces black-and-tan and tricolour dogs. A tricolour dog is black-and-tan plus white. The allele a is also called the recessive black allele and results in a solid black/brown/blue/lilac or bicolour dog. Some breeds are fixed for only one variant. The Norwegian Elkhound is fixed for the aw allele and the Beagle is fixed for the at allele. In many breeds 2 or 3 alleles are present.

The Coat Colour A-Locus test encloses the following results.

A-Locus

Coat Colour

Ay/Ay

Fawn/Sable, only allele Ay will be passed on to an offspring

Ay/aw

Fawn/Sable, either allele Ay or aw will be passed on to anan offspring

Ay/at

Fawn/Sable, either allele Ay or at will be passed on to an offspring

Ay/a

Fawn/Sable, either allele Ay or a will be passed on to an offspring

aw/aw

Wild sable/Wild type, it can only pass on allele aw will be passed on to an offspring

aw/at

Wild sable/Wild type, either allele aw or at will be passed on to an offspring

aw/a

Wild sable/Wild type, either allele aw or a will be passed on to an offspring

at/at

Tan Points/Black-and-tan/Tricolour, it can only pass on allele at will be passed on to an offspring

at/a

Tan Points/Black-and-tan/Tricolour, either allele at or a will be passed on to an offspring

a/a

Solid Black(Brown/Blue/Lilac)/Bicolour, it can only pass on allele a will be passed on to an offspring

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K-locus: H819 Coat Colour K-Locus:

The Beta-defensin gene (CBD103 gene) produces dominant black vs. brindle vs. fawn coat colours. This gene is also known as the K-locus or Dominant black gene. The coat colour is further complicated by the interaction with the E-locus and the A-locus (agouti). The Coat Colour K-Locus (H819) tests for the genetic status of the K-Locus. The K-locus has three variants (alleles). The allele KB is dominant over the alleles kbr and ky; allele kbr is dominant over allele ky. The dominant allele KB, also called dominant black allele, does not allow the agouti gene to be expressed. A dog with at least one copy of the KB allele expresses a base colour, which is determined by the B- and E-Locus. The allele kbr results in brindling and allows the agouti to be expressed but causes brindling of the agouti patterns. The A-Locus (agouti) represents several different colours, such as fawn/sable, wild sable, tan points and recessive black. The allele ky allows the agouti to be expressed without brindling. When a dog has two copies of the ky allele (homozygous ky/ky) the agouti locus determines the dog’s coat colour. The test does not discriminate between the alleles kbr and ky.

The Coat Colour K-Locus test encloses the following results:

K-Locus

Coat Colour

KB/KB

Self-colored (solid color in pigmented areas), hides expression of the A-locus, basic colour determined by B- and E-locus, only allele KB will be passed on to an offspring

KB/N

Self-colored (solid color in pigmented areas), hides expression of the A-locus, basic colour determined by B- and E-locus. The test does not discriminate between the alleles kbr and ky, N can be allele kbr or ky. The dog is KB/kbr or KB/ky, either allele KB or kbr/ky will be passed on to an offspring

N/N

The test does not discriminate between the alleles kbr and ky. N can be allele kbr or ky. The dog is kbr/kbr, kbr/ky or ky/ky. If the dog is kbr/kbr: Brindling and expression of A-locus, it can only pass on allele kbr to an offspring. If the dog is kbr/ky: Brindling and expression of A-locus, either allele kbr or ky will be passed on to an offspring. If the dog is ky/ky: Expression of A-locus without brindling, only allele ky will be passed on to an offspring.

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M-Locus: H930 Coat Colour Merle

The Silver gene (SILV gene), also called premelanosome protein (PMEL17 gene) is responsible for Merle. This gene is also known as M-Locus. Merle only dilutes eumelanin (black) pigment; dogs with two copies of the allele e (homozygous e/e) at E-Locus have no black pigment, thus do not express merle. Merle is an incompletely dominant coat color pattern characterized by irregularly shaped patches of diluted pigment and solid color. Blue and partially blue eyes are typically seen with merle, and merle dogs often have a wide range of auditory and ophthalmologic defects. Breeds with merle coat pattern are Shetland Sheepdog, Collie, Border Collie, Australian Shepherd, Cardigan Welsh Corgi, Catahoula Leopard Dog, Dachshund, Great Dane, Bergamasco Sheepdog and Pyrenean Shepherd. The Coat Colour Merle test (H930) tests for the genetic status of the M-locus. The M-locus has three variants (alleles): M (merle, SINE with longer poly-A tail), Mc (cryptic merle, SINE with shorter poly-A tail) and N (non-merle, no SINE insertion. Dogs with cryptic merle (also called phantom or ghost merle), typically display little to no merling and some may be misclassified as non-merles.

The Coat Colour Merle test encloses the following results.

M-Locus

Coat Colour

M/M

Merle coat colour, two copies of merle are present (double merle). Dog may exhibit auditory and ophthalmologic defects

M/Mc

Merle coat colour, One copy of merle and one copy of cryptic merle are present. Dog may exhibit auditory and ophthalmologic defects

M/N

Merle coat colour, one copy of merle is present. Dog may exhibit auditory and ophthalmologic defects

Mc/Mc

Cryptic-merle, two copies of cryptic merle are present. The dog is genetically healthy with regards to the merle factor

Mc/N

Cryptic-merle, one copy of cryptic merle is present, the dog is genetically healthy with regards to the merle factor

N/N

Non-merle, no copies of merle or cryptic merle are present, the dog is genetically healthy with regards to the merle factor

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H353 Coat Colour Saddle tan vs black-and-tan

The hnRNP associated with lethal yellow gene (RALY gene) defines whether tan points or saddle tan is expressed in Basset Hounds and Pembroke Welsh Corgi dogs. Black and tan colour is characterized by light colour on the muzzle, above the eyes (tan points) and on the undersides of the dog on otherwise dark coat. Saddle tan resembles black and tan colour but the lighter areas are expanded leaving usually only the back to have dark patch. Saddled tan dogs are usually born black-and-tan and the black recedes as the dog grows. The coat colour is further complicated by the interaction with the E-locus, K-locus, A-locus and a yet unidentified gene. In order for the saddle tan pattern or tan points to be expressed, the dog needs to have at least one copy of the E or Em allele at the E-locus, two copies of the ky allele at the K-locus and one or two copies of the at allele at the A-locus. The Coat Colour Saddle tan vs black-and-tan test (H353) tests for the genetic status of the RALY gene. The RALY gene has two variants (alleles). The allele WT is dominant and causes the saddle tan coat colour. Only when the dog has two copies of the recessive allele dup the coat colour is black-and-tan. The saddle tan coat colour is present in a limited number of dog breeds including some of the terriers, scent hounds and herding dogs. In breeds that have only tan point dogs and no saddled tan dogs, the tan pointed dogs can have any genotype for the RALY gene. This suggests that more complex interactions are behind tan points in breeds that are not able to express saddle tan.

The Coat Colour Saddle tan vs black-and-tan test encloses the following results:

RALY gene

Coat Colour

WT/WT

Saddle tan, only allele WT will be passed on to an offspring

WT/dup

Saddle tan, either allele WT or dup will be passed on to an offspring

dup/dup

Black-and-tan, only allele dup will be passed on to an offspring

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H354 Coat Colour Panda White Spotting

A mutation in the KIT-gene is associated with a white spotting pattern in German Shepherd Dogs, this pattern is  also called Panda White Spotting. The mutation is very recent, it appeared spontaneously in a female born in 2000. The gene for white-spotting is known as the S-locus (MITF-Gene), however this mutation in the German Shepherd dogs is in a different gene then the mutation causing white spotting in other dog breeds. The mutation causes white markings on the face, limbs, belly, neck, and tip of the tail, with the white being concentrated toward the front of the dog, similar to the irish spotting pattern. The amount of white can vary from dog to dog. The mutation that causes the Panda White pattern in German Shepherd dogs is in homozygous state (two copies of the mutation) considered embryonic lethal as no live dogs with the pattern and with two copies of the mutation have been observed. This means that pups that are homozygous for the Panda mutation do not develop in the uterus and are reabsorbed very early in the development process. Dogs that are heterozygous (one copy of the mutation) do not have any health defects associated with the Panda pattern. The Coat Colour Panda White Spotting test (H354) tests for the genetic status of the KIT-gene. This gene has two variants (alleles), P and N. The allele P is dominant. One copy of the P allele results in dogs with the Panda white pattern. Two copies of the P allele result in early embryonic death. The allele N does have no effect on the coat colour.

The Coat Colour Panda White Spotting test encloses the following results.

KIT-gene

Coat Colour

N/N

No Panda White spotting unless modified by other colour modifying factors, only allele N will be passed on to an offspring

N/P

Panda White spotting, either allele N or P will be passed on to an offspring

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H-Locus: H316 Coat Colour H-locus (Harlequin)

The 20S proteasome β2 subunit (PSMB7) gene is responsible for the Harlequin coat pattern in Great Danes. This gene is also known as H-Locus. Harlequin is a pattern resulting from interaction of the Merle (M-locus) gene and the Harlequin (H-locus) gene on black pigment. The Harlequin gene can modify the Merle gene. The Harlequin pattern is only expressed if on the M-locus at least one copy of the M allele is present in combination with at least one copy of the E or Em allele on the E-locus. Dogs that are not merle, or only have red pigment, cannot express the Harlequin gene. The dominant Merle gene, by itself produces dark spots on a diluted background. If a Merle dog also inherits one copy of the Harlequin gene, the dark spots increase in size and the background pigment is removed (turns white). The Harlequin mutation in Great Danes is in homozygous state (two copies of the mutation) considered embryonic lethal as no live dogs with two copies of the mutation have been observed. This means that pups that are homozygous for the Harlequin mutation do not develop in the uterus and are reabsorbed very early in the development process. Therefore all Harlequin patterned dogs have only 1 copy of the Harlequin mutation. The Coat colour H-locus (Harlequin) test (H316) tests for the genetic status of the H-locus. This gene has two variants (alleles), H and N. The allele H is dominant. One copy of the H allele, together with at least one copy of both the M allele for the M-locus and the E allele for the E-locus results in dogs with the Harlequin pattern. Two copies of the H allele result in early embryonic death. The allele N does have no effect on the coat colour.

The Coat colour H-locus (Harlequin) test encloses the following results.

H-Locus

Coat Colour

N/N

No Harlequin pattern unless modified by other colour modifying factors, only allele N will be passed on to an offspring

N/H

Harlequin mutation is present. In order to express the Harlequin pattern the dog must carry at least one copy of both the M-allele for the M-locus and the E-allele for the E-locus. Either allele N or P will be passed on to an offspring

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S-locus: H326 Coat Colour Piebald

The white spotting patterns that occur in many dog breeds do not have a uniform genetic basis. The Microphthalmia Associated Transcription Factor gene (MITF gene) is associated with many white spotting patterns. This gene is also known as the S-Locus. There are three major white spotting patterns described. One pattern is called “Irish spotting” and is a symmetrical pattern with white markings on the undersides, collar and muzzle, and/or blaze as demonstrated by breeds such as the Boston Terrier, Corgi, Bernese Mountain dog and Basenji. Another pattern of less symmetrical white spotting in which random white spots occur on the body of the dog is often called piebald, parti or random white and is observed in several breeds, including the Beagle and Fox Terrier. The third major pattern is called extreme white and results in a dog that is almost entirely white but usually has at least some color on the head. Furthermore, there is a pattern called mantle, this pattern is similar to Irish spotting but with more white extending onto the thigh and up the torso, as seen in some Great Danes. Another pattern that is similar to Irish spotting is called flash or pseudo-Irish and occurs in Boxers. A mutation found in the MITF gene is associated with the piebald spotting pattern in more than 25 different dog breeds. The Coat Colour Piebald test (H326) tests for the genetic status of this mutation. It results in two variants (alleles). The allele N does not produce a piebald pattern, therefor dogs with two copies of the N allele do not display the piebald pattern. The allele S is associated with the piebald pattern, however the amount of white spotting expressed varies from breed to breed and among individuals within a breed. In many breeds such as Collie, Great Dane, Italian Greyhound, Shetland Sheepdog, Boxer and Bull Terrier, piebald behaves as a dosage-dependent trait. In those breeds the allele S is semi-dominant. One copy of the S allele (S/N) results in a limited white spotting pattern. Dogs with two copies of the  S allele (S/S) display more extreme white with colour only on the head and perhaps a body spot. In Boxers and Bull Terriers, dogs that have two copies of the S allele (S/S) are completely white while dogs that only have one copy of the S allele (N/S) display the mantle pattern (called flash in these breeds). However, additional mutations in MITF or other white-spotting genes that affect the amount of white being expressed appear to be present in these breeds. In some other breeds, the allele S is recessive and in those breeds two copies are needed to produce the piebald pattern.

The Coat Colour Piebald test encloses the following results:

MITF gene

Coat Colour

S/S

Dog has two copies of the piebald mutation, the amount of white spotting expressed depends on the breed and varies among individuals within a breed, see description above, only allele S will be passed on to an offspring

S/N

Dog has one copy of the piebald mutation, the amount of white spotting expressed depends on the breed and varies among individuals within a breed, see description above, either allele S or N will be passed on to an offspring

N/N

No piebald spotting, only allele N will be passed on to an offspring

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C-Locus

Unfortunately, for this coat colour no DNA-test has been described in the scientific literature yet. As the inheritance of the coat colour may be only partially defined, for a description of coat colour C-Locus we refer to Schmutz SM and Berryere TG., (2007) Genes affecting coat colour and pattern in domestic dogs: a review. Anim Genet 38, 539-549.

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G-Locus

Unfortunately, for this coat colour no DNA-test has been described in the scientific literature yet. As the inheritance of the coat colour may be only partially defined, for a description of coat colour G-Locus we refer to Schmutz SM and Berryere TG., (2007) Genes affecting coat colour and pattern in domestic dogs: a review. Anim Genet 38, 539-549.

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I-Locus

Unfortunately, for this coat colour no DNA-test has been described in the scientific literature yet. As the inheritance of the coat colour may be only partially defined, for a description of coat colour I-Locus we refer to Schmutz SM and Berryere TG., (2007) Genes affecting coat colour and pattern in domestic dogs: a review. Anim Genet 38, 539-549.

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P-Locus

Unfortunately, for this coat colour no DNA-test has been described in the scientific literature yet. As the inheritance of the coat colour may be only partially defined, for a description of coat colour P-Locus we refer to Schmutz SM and Berryere TG., (2007) Genes affecting coat colour and pattern in domestic dogs: a review. Anim Genet 38, 539-549.

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R-Locus

Unfortunately, for this coat colour no DNA-test has been described in the scientific literature yet. As the inheritance of the coat colour may be only partially defined, for a description of coat colour R-Locus we refer to Schmutz SM and Berryere TG., (2007) Genes affecting coat colour and pattern in domestic dogs: a review. Anim Genet 38, 539-549.

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T-Locus

Unfortunately, for this coat colour no DNA-test has been described in the scientific literature yet. As the inheritance of the coat colour may be only partially defined, for a description of coat colour T-Locus we refer to Schmutz SM and Berryere TG., (2007) Genes affecting coat colour and pattern in domestic dogs: a review. Anim Genet 38, 539-549.

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COAT VARIATON:

There are three variables involved in canine coat type: hair length, the presence of furnishings, and the presence of curly hair. When genotyping genetic variants on all three genes, there are a few coat patterns that can be discriminated. In the table below the possible combinations of these mutations are indicated.

Hair Lenght (FGF5)

Improper Coat/

Furnishings (RSPO2)

Curly Coat (KRT71)

 Coat type

S/L or S/S

IC/IC

N/N

Short (no furnishings, non-curly)

S/L or S/S

IC/IC

N/CC or CC/CC

Short (no furnishings, curly)

S/L or S/S

N/N or N/IC

N/N

Wire (short, furnishings, non-curly)

S/L or S/S

N/N or N/IC

N/CC or CC/CC

Wire and Curly (short, furnishings, curly)

L/L

IC/IC

N/N

Long (no furnishings, non-curly)

L/L

N/N or N/IC

N/N

Long with Furnishings (long, furnishings, non-curly)

L/L

IC/IC

N/CC or CC/CC

Curly (long, no furnishings, curly)

L/L

N/N or N/IC

N/CC or CC/CC

Curly with Furnishings (long, furnishings, curly)

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H765 Hair length

The Fibroblast Growth Factor 5 (FGF5) determines the hair length. The Hair Length test (H765) tests for the genetic status of the FGF5-gene and has two variants (alleles). The allele S is dominant and results in short hair. Only when the dog has two copies of the recessive allele L the dog has long hair. Some breeds, such as Labradors, are fixed for the dominant allele S. Other breeds, such as Poodles, are fixed for the recessive allele L and some breeds, such as Dachshund, can have either long or short hair. In some breeds another, yet unidentified, mutation is present that influences hair length. This unidentified mutation is known to occur in Afghan Hounds, Yorkshire Terriers, and Silky Terriers.

The Hair Length test encloses the following results:

Result Hair Length test

Hair Length

L/L

Long Hair, unless modified by another mutation influencing hair length

S/L

Short Hair, unless modified by another mutation influencing hair length

S/S

Short Hair, unless modified by another mutation influencing hair length

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H848 Improper Coat /Furnishing

The R-spondin 2 (RSPO2) gene influences both the wiry texture and a growth pattern of the coat. The growth pattern of the coat, also known as “furnishings”, increases hair growth on the face and legs and is typified by the canine moustache and eyebrows. The term "furnishings" refers to the longer mustache and eyebrows seen in wire-haired dogs and other breeds. In breeds such as the Portuguese Water Dog, Labradoodle and Goldendoodles furnishings can be variable, but are the breed standard. Portuguese Water Dogs without furnishings are referred to as having an "Improper Coat" which is characterized by short hair on the head, face and legs. The Improper Coat/Furnishings test (H848) tests for the genetic status of the RSPO2 gene. The RSPO2 gene has two variants (alleles). The allele N is dominant and results in “furnishings”. Only when the dog has two copies of the recessive allele IC the dog does not have “furnishings”. Some breeds, such as the Airedale Terrier, are fixed for the dominant allele N.

The Improper Coat/Furnishings test encloses the following results:

Result Improper Coat/Furnishings test

Coat

N/N

Dog has furnishings in some breeds this means dog has a normal coat with longer hair on the muzzle and eyebrows

N/IC

Dog has furnishings in some breeds this means dog has a normal coat with longer hair on the muzzle and eyebrows

IC/IC

Dog does not have furnishings, in some breeds this means an Improper coat without longer hair on the muzzle and eyebrows

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H921 Curly Coat

The Keratin 71 (KRT71) gene influences the hair formation. The Curly Coat test (H921) tests for the genetic status of the KRT71 gene. The KRT71 gene has two variants (alleles). The allele CC is dominant and results in a curly coat. Only when the dog has two copies of the recessive allele N the coat is of a non-curly type. Some breeds, such as the Irish Water Dog, are fixed for the dominant allele CC. Other breeds, such as Kuvasz, can have either curly or non-curly hair.

The Curly Coat test encloses the following results:

Result Curly Coat test

Coat

CC/CC

Curly coat, unless modified by another mutation influencing hair formation

N/CC

Curly coat,  unless modified by another mutation influencing hair formation

N/N

Non-curly coat, unless modified by another mutation influencing hair formation

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Date: 4th October 2017, version 9