Tan Points (at)

A dog with a tan point pattern has a solid base color with white, yellow or red markings on the muzzle, eyebrows, chest, underside, lower legs, and under the tail. Although this pattern is also called black back or black-and-tan the base color can also be liver, blue, or lilac.

What is a Black Back Pattern?

Dogs with a black & tan phenotype have symmetrical tan markings on an otherwise eumelanin-pigmented coat. These lighter markings can be white, yellow, or red and can be found on the muzzle, eyebrows, throat, chest, belly, lower legs, and under the tail.

The small markings above the eyes are sometimes called pips.

Interestingly, dogs with a saddle pattern will also be born with a traditional tan point phenotype.

Most of us know this phenotype as tan point or black-and-tan. But since the newer term black back is used by some testing companies, we should probably also get used to it.

The ASIP^BB allele (a^t)

The A Locus (ASIP) controls pigment distribution of phaeomelanin and eumelanin.

To have tan points, a dog has to be able to express ASIP.

A tan point dog can’t be dominant black (K^B/-) at the K-Locus or recessive red (e/e) at the E-Locus.

Tan points were one of the phenotypes the old A-Locus testing system could detect: A^y (sable) >a^w (agouti) >a^t (tan point) >a (recessive black). But the old A-Locus test couldn’t detect all versions of a^t nor could it tell the difference between traditional tan points and saddle pattern (both tested as a^t).

A newly developed test can now distinguish between six different patterns:

ASIPDY	Ay	Dominant Yellow, Clear Sable
ASIPSY	Ays	Shaded Yellow, Shaded Sable
ASIPAG	aw	Agouti, Wolf Grey
ASIPBS	asa	Black Saddle
ASIPBB	at	Black Back, Tan Point
ASIPa	a	Recessive Black

Black back (ASIP^BB or at) is the second-most recessive trait at the A-Locus. Dogs that carry recessive black (at/a) will often display smaller tan markings compared to homozygous a^t/a^t dogs.

Black back is caused by a particular combination of two ASIP promoters:

The wild-type ventral promoter (VP2) gives traditional tan markings. The loss-of-function hair cycle promoters (HCP3, HCP4 or HCP5) disable hair banding on the dog’s back so the coat stays black.

Any combination of a wild-type ventral promoter and a non-functional hair cycle promoter (VP2-HCP3, VP2-HCP4, VP2-HCP4) represents the new black back allele a^t. Other promoter combinations (we call these haplotypes) represent the other alleles of the A-Locus series.

Phenotype	Allele	VP	HCP
Dominant Yellow	Ay	VP1	HCP1
Shaded Yellow	Ays	VP2	HCP1
Agouti	aw	VP2	HCP2
Black Saddle	asa	VP1	HCP4
Black Back	at	VP2	HCP3,4,5
Recessive Black	a	(VP2)	(HCP3)

Black Back Patterns

Dogs with a tan point pattern have a dark base color with lighter markings on the muzzle, eyebrows, chest, underside, lower legs, and under the tail. They have very specific facial markings and a dark ridge running down the nose which is also called a nose bar.

The size of tan markings can be smaller in recessive black carriers (at/a). And markings can be slightly bigger in some dogs that are recessive red carriers (E/e) or domino carriers (E/eA, E/eG).

Dogs can have “running tan” where the black around the eyes recedes without being creeping tan. Some dogs with a black and tan pattern even have tan spectacles or are somewhat open-faced.

Tan markings can have very crisp edges, but in some cases they can also be smudgy. Some dogs have sooty points or black marks in their tan, especially on the toes (called penciling or thumbmark).

Additionally, there are many traits that can modify how a black-and-tan will actually look.

Let’s go through some examples:

Phaeomelanin Intensity

The lighter markings in a black back pattern are pigmented by phaeomelanin. Some traits can affect the color intensity causing a range from solid white to cream, yellow, orange, or red.

Black-and-silver Miniature Schnauzers are an example of very light phaeomelanin intensity while most dog breeds express yellow to red tan points.

Tan Point Countershading

In some dogs, phaeomelanin is darker on a dog’s back than on his belly, throat or muzzle. This is called countershading or urajiro in some Japanese breeds.

Countershading can cause very light areas with very defined edges. Since countershading only affects phaeomelanin, it can create an interesting color transition inside the tan markings.

Eumelanin Color

Although this pattern is commonly called black-and-tan, the eumelanin base color can be black, liver, blue, or lilac. What color a dog’s eumelanin has depends on its genotype at the B-Locus and D-Locus.

So some dogs are blue-and-tan or liver-and-tan while lilac-and-tan is quite rare and mostly found in color-bred dogs.

Brindle Point

If a dog has a brindle variant at the K-Locus (k^br/-), it will express eumelanin-pigmented stripes on top of all coat phaeomelanin in their pattern.

So a black & tan dog with brindle will produce black stripes on all of his tan markings. A blue-based dog will have blue stripes and so on.

A brindled tan point phenotype is also called brindlepoint.

Black Back and Mask

Masks (Em/-) cause additional eumelanin on a dog’s muzzle but can extend beyond the face and cause even more eumelanin on the rest of the body.

On top of a tan point pattern, masks can cover some of the tan markings on the face and in more extreme cases even on the chest or the lower legs.

Black Back and White

A dog with tan points and white is commonly called tricolor since it has “three colors” (black-and-tan-and-white). White hides some of the original base pattern.

Depending on its eumelanin color, different phenotypes are called black tri, chocolate tri, blue tri, or lilac tri. Examples for dogs with a tricolored coat can be found in many dog breeds like Australian Shepherds, Bull Terriers, Bernese Mountain Dogs and Shelties, Border Collies, or Collies.

Black Back and Ticking

On some tricolor dogs, some of the color lost due to white spotting can return after birth.

Pigmented spots that appear inside of white markings will show some of the color of the hidden base pattern. So on black-and-tan dogs, dots will be black or tan depending on their location.

Ticked black and tan dogs are very common in Cocker Spaniels, English Setters, or Australian Cattle Dogs. Most breeds call heavy black ticking “blue” (e.g. Blue Heeler, Bluetick Coonhound, etc.).

Black Back and Graying

Progressive greying causes a dog’s eumelanin color to fade. This turns black to gray and brown to beige.

This trait can only affect dogs with furnishings such as Poodles or Tibetan Terriers.

Black Back and Merle

Merle deletes some eumelanin from the original base pattern, it rarely affects phaeomelanin. So only the black coat on a black-and-tan dog will be affected by Merle.

Many breeds with black-and-tan or tricolor and merle can be found in the herding group, e.g. in Australian Shepherds, Border Collies, Shelties, or Collies.

Black Back and Domino

Domino inhibits eumelanin production. The eumelanin coat recedes which creates larger areas with phaeomelanin. The tan coat and undercoat also can have a lighter shade than expected.

Tan point dominos typically have extended tan markings from birth. Their black mantle can look grayish from having pale hair roots and a light undercoat. They often have a residual nose bar, black ear rims, and a widow’s peak (resembling a shaded sable pattern). Some dogs lose more eumelanin than others.

Domino is a rare trait found only in a comparatively small number of dog breeds. There are different versions of domino around that all seem to work in a similar way:

Ancient domino affects northern breeds but also occurs in some hounds and a variety of other breeds. It is the reason for some of the typical facial patterns of Siberian Huskies or Alaskan Malamute.

Grizzle Domino occurs in sighthound breeds. And Cocker Sable is a rare breed-specific version only found in (you guessed it!) English Cocker Spaniels and American Cocker Spaniels.

Dog Breeds with Tan Points

Tan points give a very distinct look and are found in very many dog breeds. Here are some examples:

• Afghan Hound
• Australian Cattle Dog
• Australian Kelpie
• Australian Shepherd
• Basenji
• Bearded Collie (rare)
• Beauceron
• Bernese Mountain Dog
• Black and Tan Coonhound
• Border Collie
• Borzoi
• Bull Terrier
• Catahoula Leopard Dog
• Cavalier King Charles Spaniel
• Chinook
• Chihuahua
• Cocker Spaniel
• Collie
• Danish Swedish Farmdog
• Dachshund
• Dobermann
• English Setter
• English Springer Spaniel
• English Toy Terrier
• Eurasier
• Finnish Lapphund
• German Hunting Terrier
• German Shepherd Dog
• Grand Bleu de Gascogne
• Gordon Setter
• Hovawart
• Lancashire Heeler
• Lapponian Herder
• Manchester Terrier
• Miniature Pinscher
• Miniature Schnauzer
• Pomeranian
• Poodle
• Prague Ratter
• Rottweiler
• Saluki
• Russkiy Toy
• Sheltie
• Shiba
• Siberian Husky
• Tibetan Mastiff
• Tibetan Spaniel
• Tibetan Terrier
• Welsh Corgi

Learn More

Links

[1] Bannasch, D.L., Kaelin, C.B., Letko, A. et al. Dog colour patterns explained by modular promoters of ancient canid origin. Nat Ecol Evol 5, 1415–1423 (2021). https://doi.org/10.1038/s41559-021-01524-x

[2] Dreger DL, Schmutz SM. A SINE insertion causes the black-and-tan and saddle tan phenotypes in domestic dogs. J Hered. 2011 Sep-Oct;102 Suppl 1:S11-8. PMID: 21846741. https://doi.org/10.1093/jhered/esr042

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