Coat (dog)

For other uses, see Coat (disambiguation).
Montage showing the coat variation of the dog.

The coat of the domestic dog (Canis lupus familiaris) refers to the hair that covers its body. A dog's coat may be a double coat, made up of a soft undercoat and a tougher topcoat, or a single coat, which lacks an undercoat. Double coats have a top coat, made of stiff hairs to help repel water and shield from dirt, and an undercoat to serve as insulation.[1] The terms fur and hair are often used interchangeably when describing a dog's coat, however in general, a double coat, e.g., like that of the Newfoundland and most mountain dogs, is referred to as a fur coat, while a single coat, like that of the Poodle, is referred to as a hair coat.

Colors, patterns, lengths and textures

Newfoundland lying next to its combed-out seasonal undercoat.

There are a greater variety of coat colors, patterns, lengths and textures found in the domestic dog than in its wolf relations, even though dogs and wolves belong to the same species (Canis lupus). Different breeds use different names for longhaired and shorthaired types, there is no standard nomenclature for length, breed standards give acceptable lengths by measurement. Coat colors in dogs were not likely initially selected for by humans but were probably the inadvertent outcome of some other selection process (i.e. selection for tameness).[2] Research has found that tameness brings associated physical changes, including coat coloring and patterning.[3]

Domestic dogs often display the remnants of countershading, a common natural camouflage pattern. The basic principle of countershading is when the animal is lit from above, shadows will be cast on the ventral side of the body. These shadows could provide a predator or prey with visual cues relating to the movement of the animal. By being lighter colored on the ventral side of the body, an animal can counteract this, and thereby fool the predator or prey. An alternative explanation is that the dorsal and ventral sides of an animal experience different selection pressures (from the need to blend into different backgrounds when viewed from above and below) resulting in differing coloration.[4]

Genetic basis of color and pattern

Close up of a greyhound's short-haired single coat.
Flakes and greasy coat
Black-coated Chow-Chow whose long hair has faded due to exposure to the elements.
Creamy-white-coated French Bulldog

Modern breeds of dog exhibit a diverse range of coat colorings, patterns, lengths and textures. In recent years, the understanding of the genetic basis for coat coloring and patterning[5] and coat length and texturing[6] has increased significantly.

There are currently eight known genes within the canine genome that are associated with coat color. Each of these genes occurs in at least two variants, or alleles, which accounts for the variation in coat color between animals. Each of these genes exists at a fixed location, or locus, of the animal's genome. The loci associated with canine coat color are:

A (agouti) locus

The alleles at the A locus are related to the production of agouti signalling protein (ASIP) and determine whether an animal expresses an agouti appearance, and if so what type, by controlling the distribution of pigment in individual hairs. There are five suspected alleles that occur at the A locus:

Most texts suggest that the dominance hierarchy for the A locus alleles appears to be as follows: Ay > aw > at > a, however research suggests the existence of pairwise dominance/recessive relationships in different families and not the existence of a single hierarchy in one family.[9] This means, for example, that Ay may be incompletely dominant over at. Recent studies reveal saddle tan to be a modification of the tanpoint phenotype caused by interaction of other genes with ASIP.

B (brown) locus

The alleles at the B locus are related to the production of tyrosinase related protein 1 (TYRP1) and determine the degree to which an animal expresses tyrosinase, an enzyme related to the production of melanin, in its coat and skin (including the nose and paw pads). There are two known alleles that can occur at the B locus:

B is dominant to b. An animal that has at least one copy of the B allele will have a black nose, paw pads and eye rims while an animal that is homozygous for any of the b alleles will have a liver nose, paw pads and eye rims.

D (dilute) locus

The alleles at the D locus (the melanophilin gene or MLPH) are related to the dilution of eumelanin and/or phaeomelanin and determine the intensity of pigmentation. There are two known alleles:

D is dominant to d. Homozygosity of d is sometimes accompanied by hair loss and recurrent skin inflammation, a condition referred to as either color dilution alopecia (CDA) or black hair follicular dysplasia (BHFD) depending upon the breed of dog.[10]

E (extension) locus

The alleles at the E locus (the melanocortin receptor 1 gene or MC1R) determines whether an animal expresses a melanistic mask or a grizzle overlay, as well as determining whether an animal expresses eumelanin in its coat. Expression of eumelanin will result in a black or brown coat, while a lack of expression of eumelanin will result in a red or yellow coat. There are four known alleles that occur at the E locus:

The dominance hierarchy for the E locus alleles appears to be as follows: Em > EG > E > eh > e. The Grizzle allele has been studied only in Salukis and Afghan Hounds, the latter in which it is referred to as "Domino". Its placement in the dominance hierarchy has not been solidified. The eh sable extension allele has been studied only in English Cocker Spaniels and produces sable in the presence of all K locus alleles. The expression is dependent upon the animal being homozygous for at and not possessing Em or E. The expression of EG is dependent upon the animal being homozygous for at and not possessing Em or KB.[11] An animal that is homozygous for e will express a red or yellow coat regardless of the alleles at other loci (unless the animal is homozygous for ca at the C locus in which case it will be albino).

H (harlequin) locus

DNA studies have not yet isolated the gene at the H locus, but the traits associated with it have been mapped to chromosome 9.[12] The H locus is a modifier locus (of the M locus) and the alleles at the H locus will determine if an animal expresses a harlequin pattern (white base with black patches). There are two alleles that can occur at the H locus:

H is dominant to h. Breeding data suggests that H is embryonic recessive lethal and that therefore all harlequins are H/h.[12] The Harlequin allele is specific to Great Danes. As H is a modifier locus of the M locus, in order for the Harlequin pattern to be expressed, one copy of the H allele (at the H locus) and one copy of the M allele (at the M locus) must be present (i.e. H/h and M/m).

K (dominant black) locus

The alleles at the K locus (the β-Defensin 103 gene or DEFB103) determine the coloring pattern of an animal's coat.[13] There are three known alleles that occur at the K locus:

The dominance hierarchy for the K locus alleles appears to be as follows: KB > kbr > ky. The coloring of an animal that possesses at least one KB will be determined by the alleles it possesses at the B and E loci. An animal with one kbr allele and no KB allele will express a brindle pattern to its coat unless it is homozygous for e (at the E locus) or possibly homozygous for a (at the A locus). An animal that is homozygous for ky will express the agouti pattern in accordance with the alleles it has at the A locus.

M (merle) locus

The alleles at the M locus (the SILV gene) determine whether an animal expresses a merle pattern to its coat (patches of sporadic colored and white hairs and other patches of solid color). There are two alleles that can occur at the M locus:

M is dominant to m. Both heterozygosity and homozygosity of the merle gene (i.e. M/m and M/M) are linked to a range of auditory and ophthalmologic abnormalities.[14]

S (spotting) locus

The alleles at the S locus (the microphthalmia-associated transcription factor gene or MITF) determine the degree and distribution of spotting of an animal's coat.[15] There is disagreement as to the number of alleles that occur at the S locus, with researchers postulating either two[16] or four[17] alleles. The four alleles postulated are:

S is dominant to s. DNA studies have not yet confirmed the existence of all four alleles, with some research suggesting the existence of at least two alleles (S and sp)[15] and other research suggesting the possible existence of a third allele (si).[18] It has been suggested that what appears to be the result of an sw allele is in fact the result of plus and minus modifiers acting on one of the other alleles.[15] It is thought that the spotting that occurs in Dalmatians is the result of the interaction of three loci (the S locus, the T locus and F locus) giving them a unique spotting pattern not found in any other breed.[19]

In 2014, a study found that a simple repeat polymorphism in the MITF-M Promoter is a key regulator of white spotting and that white color had been selected for by humans.[20][21]

Postulated color and pattern loci

There are at least five additional theoretical loci thought to be associated with coat color in dogs. DNA studies are yet to confirm the existence of these genes or alleles but their existence is theorised based on breeding data:[22]

C (colored) locus

The alleles at the theoretical C locus are thought to determine the degree to which an animal expresses phaeomelanin, a red-brown protein related to the production of melanin, in its coat and skin. Five alleles are theorised to occur at the C locus:

The C locus in dogs is not well understood and the theorised alleles are based on those present in other species.[17] True albinism has not been conclusively shown to exist in dogs. It is thought that an animal that is heterozygous for the C allele with one of the other alleles will express a result somewhere between the two alleles.[23]

F (flecking) locus

The alleles at the theoretical F locus are thought to determine whether an animal displays small, isolated regions of white in otherwise pigmented regions (not apparent on white animals). Two alleles are theorised to occur at the F locus:

It is thought that F is dominant to f.[19]

G (progressive greying) locus

The alleles at the theoretical G locus are thought to determine if premature greying of the animal's coat will occur. Two alleles are theorised to occur at the G locus:

It is thought that G is dominant to g.

I (intensity) locus

The alleles at the theoretical I locus are thought to affect phaeomelanin expression. Two alleles are theorised to occur at the I locus:

It is thought that I and i are co-dominant, so that animals with i/i will be paler than animals with I/i.

T (ticking) locus

The alleles at the theoretical T locus are thought to determine whether an animal displays small, isolated regions of pigment in otherwise white regions (not apparent on non-white animals). Two alleles are theorised to occur at the T locus:

It is thought that T is dominant to t.

Genetic basis of length and texture

Research indicates that the majority of variation in coat growth pattern, length and curl can be attributed to mutations in three genes, the R-spondin-2 gene or RSPO2, the fibroblast growth factor-5 gene or FGF5, and the keratin-71 gene or KRT71.[6]

The L (length) locus

The alleles at the L locus (the fibroblast growth factor-5 gene or FGF5) determine the length of the animal's coat.[24] There are two known alleles that occur at the L locus:

L is dominant to l. A long coat is demonstrated when a dog has pair of recessive 'l' alleles at this locus.

The W (wired) locus

Wire hair.

The alleles at the W locus (the R-spondin-2 gene or RSPO2) determine the coarseness and the presence of "facial furnishings" (e.g. beard, moustache, eyebrows).[6] There are two known alleles that occur at the W locus:

W is dominant to w. Animals that are homozygous for l (i.e. l/l) and possess at least one copy of W will have long, soft coats with furnishings, rather than wirey coats.[6]

The R (curl) Locus[note 1]

Curly hair.

The alleles at the R locus (the keratin-71 gene or KRT71) determine whether an animal's coat is straight or curly.[6] There are two known alleles that occur at the R locus:

R is dominant to r.

Interaction of Length & Texture Genes

These three genes responsible for the length and texture of an animal's coat interact to produce eight different phenotypes:[6]

Hair growth

The Puli's coat forms cords as it grows.
Hairless and Coated Xoloitzcuintli.

The coat of most dogs grows to a specific length and then stops growing, while the coats of some dogs grow continuously in a manner similar to human hair growth. A long-coated dog with a single dominant furnishings allele (wire coat), will demonstrate this feature. Examples of breeds of dog whose coats grow continuously are:

Corded Coats

Corded coats, like those of the Puli and Komondor are thought to be the result of continuously growing curly coats. Other breeds with continuously growing curly coats, such as the Poodle, can also be groomed to cord.

Hairless

Some breeds of dog do not grow hair on parts of their bodies and may be referred to as "hairless". Examples of "hairless" dogs are the Xoloitzcuintli (Mexican Hairless Dog), the Peruvian Inca Orchid (Peruvian Hairless Dog) and the Chinese Crested. Research suggests that hairlessness is caused by a dominant allele, which is homozygous lethal.[25]

Genetic testing and phenotype prediction

In recent years genetic testing for the alleles of some genes has become available[26] Software is also available to assist breeders in determining the likely outcome of matings.[27]

Nomenclature of colors and patterns

Colors

The same color may be referred to differently in different breeds. Likewise, a same term may mean different colourations in different breeds.

Brown, chocolate, liver

Brown, chocolate and liver are the most common terms used to refer to the bb-dilution of black pigment to a dark brown. Depending on breed and exact shade, terms such as mahogany, midtone brown, grey-brown, blackish brown are used. Sedge and deadgrass are used to describe the desired Chesapeake Bay Retriever color that resembles "that of its working surroundings" as closely as possible.

Red

Red refers to reddish shades of orange, brown, and tan. Terms used include orange, red-gold, cinnamon, tan, and ruby. Genetically a dog called red is usually a clear sable (with little to no eumelanin tipping on hairs) or a ruddy recessive yellow.

In some breeds, "red" refers to what would usually be called brown, chocolate, or liver. A "red merle" is always a liver-based merle. In Australian Cattle Dogs, blue stands for a densely ticked liver-based colouration with an overall red-grey appearance.

Gold and yellow

Gold refers specifically to a rich reddish-yellow and its variants, whereas yellow can refer to any shade of yellow and tan. Terms used include yellow-gold, lion-colored, fawn, apricot, wheaten, tawny, straw, yellow-red, mustard, sandy, honey, apricot, blond, lemon. Dogs called golden or yellow tend to be recessive yellow, but can also be sable.

Cream

Cream refers to a pale yellowish or tannish colour which can be almost white.

Fawn

Fawn typically refers to a yellow, tan, light brown, or cream dog that has a dark melanistic mask.

With Weimaraners, fawn refers to their typical brownish grey colouration that with other breeds is usually called lilac.

Black

Black is a pure black that can get grizzled as the dog ages, or have a tendency to gain a brownish cast when exposed to the elements.

Blue

Blue is a cool-toned, metallic grey. It typically means a dd-dilution of black pigment, a grey colouration that is grey from birth, but has a wide range of breed-specific meanings.

In Kerry Blue Terriers, Poodles, and Bearded Collies, "blue" refers to colouration that is black at birth and progressively greys out as the dog matures. In Australian Shepherds, Rough Collies, and Shetland Sheepdogs, blue means a blue (black-based) merle. In Australian Silky Terriers, blue means a saddle-type black and tan pattern, where the black parts of the coat progressively fade to a steel grey as the dog matures, and in Australian Cattle Dogs, blue stands for a densely ticked black-based colouration with an overall blue-grey appearance.

Grey

Grey simply means a grey colouration of any shade. It can be used as an alternative synonym of blue, but tends to mean some other type of grey than the dd-dilution of black ("true" blue). Synonyms include silver, pepper, grizzle, slate, blue-black grey, black and silver, steel. Greys of a dusty or brownish cast are often lilac, a dd-dilution of liver, and this colouration does not have much of a commonly recognised name. Across various breeds, it is called lavender, silver-fawn, isabella, fawn, café au lait or silver beige.

In Poodles, a blue is a very slowly fading, very dark steel grey, whereas a silver is a quicker to clear, much lighter grey that can range from a pale platinum to a steel grey. Both are black at birth with minimal markings to indicate future change. Similarly, café au lait is a slower and darker and silver beige a quicker and lighter progressively greying brown, i.e. liver.

White

White: Such a light cream that it is seen and described as pure white, making them distinct from albino dogs. A white dog, as opposed to an albino one, has dark pigment around the eye rims and nose, often coupled with dark-colored eyes. There is often some coat identifiable as cream between the dog's shoulder blades.

Patterns

The same pattern may be referred to differently in different breeds.


Liver and tan Australian Kelpie
Black and tan Rottweiler		 Black and tan, liver and tan, blue and tan: Coat has both colors but in clearly defined and separated areas, usually with the darker color on most of the body and tan (reddish variants) underneath and in highlights such as the eyebrows. Black and brindle and liver and brindle, in which the same pattern is evident with brindling in place of tan, are also possible, but less common.

Black and white Border Collie
Blenheim (Red-brown and white) Cavalier King Charles Spaniel		 Bicolor (also called Two-color, Irish spotted, Flashy, Patched, Tuxedo) Any color or pattern coupled with white spotting. This can range anywhere from white toes and tail tip to a mostly-white dog with color around the base of the ears and tail. Some breeds have special names for the color combinations; for example, Cavalier King Charles Spaniel uses Blenheim for reddish brown (chestnut) and white. Irish Spotted or flashy pattern is symmetrical and includes a white chest, white band around the neck, white belly, and white feet or "boots." This pattern is commonly seen in herding dogs, and Boxers, among others. The piebald gene is responsible for this pattern.

Black tricolor Entlebucher Mountain Dog
Tricolor Beagle		 Tricolor: Three clearly defined colors, usually either black, liver, or blue on the dog's upper parts, white underneath, with a tan border between and tan highlights; for example, the Smooth Collie, the Rough Collie, the Papillon,or the Sheltie. Tricolor can also refer to a dog whose coat is patched, usually two colors (such as black and tan) on a white background.

Blue merle tricolor Shetland Sheepdog
Red merle Catahoula Leopard Dogs		 Merle: Marbled coat with darker patches and spots of the specified color. Merle is referred to as "Dapple" with Dachshunds.

Tuxedo Lab mix.
Tuxedo Collie mix		 Tuxedo: Solid (often black) with a white patch (shirt front) on the chest and chin, and white on some or all of the feet (spats.) The tuxedo pattern is common in dogs that carry only one piebald gene (a heterozygous carrier).

Harlequin Great Dane
Harlequin Great Dane		 Harlequin: "ripped" splotches of black on white. The Great Dane is the only breed with this pattern. Sometimes, like with the parti-colored poodle Poodle, the term 'harlequin is incorrectly used to describe the coat pattern, but the gene responsible for the patches of color in some poodles is piebald, which is present in many dog breeds and most of the ones which some white on their coats.

Spotted Dalmatian
Spotted mutt in Sinamaica, Venezuela		 Spotted Coin-sized pigmented spots on a white background. The spotting on Dalmatians is unique as it involves mutations in at least three different spotting genes.[19]

Red-speckled Australian Cattle Dog
Liver-ticked German Shorthaired Pointer		 Flecked, ticked, speckled: also called belton in English Setters

Orange belton (orange and white speckled) English Setter
Blue speckled Australian Cattle Dog

Densely brindled liver and white Boston Terrier
Very sparsely brindled Great Dane		 Brindle: A mixture of black/liver/blue/lilac and red/yellow/cream arranged in a vertical "tiger stripe" pattern.

Airedale Terrier with large black saddle
Norwegian Dunker with merle-affected black saddle		 Saddle or blanket: A different color, usually darker, over the centre of the back.

Dark orange sable Pomeranian
Clear sable Australian Terrier		 Sable: Black-tipped hairs; the rest of the hair can be gold to yellow, silver, grey, or tan. The darkness of the coat depends on how much of each hair is black versus the lighter color. Totally clear sables might only have black in their whiskers.

Show coats

The nature and quality of a purebred dog's coat is important to the dog fancy in the judging of the dog at conformation shows. The exact requirements are detailed in each breed's breed standard and do not generalise in any way, and the terminology may be very different even when referring to similar features. See individual breed articles for specific information.

Shedding

A slicker brush with wire bristles, used for removing loose hair from the coat.

Every hair in the dog coat grows from a hair follicle, which has a three phase cycle, as do most mammals. These cycles are: anagen, growth of normal hair; catagen growth slows, and hair shaft thins; telogen, hair growth stops, the follicle rests, and the old hair falls off—is shed. At the end of the telogen phase, the follicle begins the cycle again.[28]

Hypoallergenic coats

The Portuguese Water Dog is an example of a breed with single, low-shedding coat.

Some dog breeds have been promoted as hypoallergenic (which means less allergic, not free of allergens) because they shed very little. However, no canine is known to be completely nonallergenic. Often the problem is with the dog's saliva or dander, not the fur.[29] Although poodles, bichons, yorkies, and terriers are commonly represented as being hypoallergenic, the reaction that an individual person has to an individual dog may vary greatly. In treating dog related allergies, it has been found that "Factors related to individual dogs seem to influence the allergenicity more than breed..."[30]

See also

Notes

  1. ↑ Researchers have not yet assigned a letter to this locus and "R" has been selected based on the use of the term "Rex" for curled hair in domestic cats.

References

  1. ↑ "How to Keep Your Dog Warm This Winter". Spoiled Pets Shop. 2014. Retrieved November 10, 2014.
  2. ↑ James Serpell, ed. (1995). The Domestic Dog: Its Evolution, Behaviour and Interactions with People. Cambridge, United Kingdom: Cambridge University Press. p. 284. ISBN 0-521-42537-9.
  3. ↑ Lyudmila N. Trut (March–April 1999). "Early Canid Domestication: The Farm-Fox Experiment". American Scientist. 87 (2): 160–169. doi:10.1511/1999.2.160.
  4. ↑ Graeme D. Ruxton; Michael P. Speed; David J. Kelly (September 2004). "What, if anything, is the adaptive function of countershading?". Animal Behaviour. 68 (3): 445–451. doi:10.1016/j.anbehav.2003.12.009.
  5. ↑ Schmutz, S. M.; Berryere, T. G. (December 2007). "Genes affecting coat color and pattern in domestic dogs: a review". Animal Genetics. 38 (6): 539–549. doi:10.1111/j.1365-2052.2007.01664.x. PMID 18052939.
  6. 1 2 3 4 5 6 Edouard Cadieu; Mark W. Neff; Pascale Quignon; Kari Walsh; Kevin Chase; Heidi G. Parker; Bridgett M. VonHoldt; Alison Rhue; Adam Boyko; Alexandra Byers; Aaron Wong; Dana S. Mosher; Abdel G. Elkahloun; Tyrone C. Spady; Catherine André; K. Gordon Lark; Michelle Cargill; Carlos D. Bustamante; Robert K. Wayne; Elaine A. Ostrander (October 2009). "Coat Variation in the Domestic Dog Is Governed by Variants in Three Genes". Science. 326 (5949): 150–153. doi:10.1126/science.1177808. PMC 2897713Freely accessible. PMID 19713490.
  7. ↑ Dreger, Dayna L. and Schmutz, Sheila M. 2011. A SINE Insertion Causes the Black-and-Tan and Saddle Tan Phenotypes in Domestic Dogs. Journal of Heredity 2011 102: S11-S18.
  8. ↑ Dreger DL, Parker H, Ostrander E, Schmutz SM. The involvement of RALY in a complex gene interaction producing the saddle tan phenotype in dogs. A presentation at Advances in Canine and Feline Genomics and Inherited Diseases 2012 Conference, Visby, Sweden. June 1, 2012.
  9. ↑ Julie A. Kerns; J. Newton; Tom G. Berryere; Edward M. Rubin; Jan-Fang Cheng; Sheila M. Schmutz; Gregory S. Barsh (October 2004). "Characterization of the dog Agouti gene and a nonagouti mutation in German Shepherd Dogs". Mammalian Genome. 15 (10): 798–808. doi:10.1007/s00335-004-2377-1. ISSN 0938-8990. PMID 15520882.
  10. ↑ Ute Philipp; Henning Hamann; Lars Mecklenburg; Seiji Nishino; Emmanuel Mignot; Anne-Rose Günzel-Apel; Sheila M Schmutz; Tosso Leeb (June 2005). "Polymorphisms within the canine MLPH gene are associated with dilute coat color in dogs". BMC Genetics. 6 (34): 34. doi:10.1186/1471-2156-6-34. ISSN 1471-2156. PMC 1183202Freely accessible. PMID 15960853.
  11. ↑ Dayna L. Dreger; Sheila M. Schmutz (Jun 2010). "A New Mutation in MC1R Explains a Coat Color Phenotype in 2 Old Breeds: Saluki and Afghan Hound". Journal of Heredity. 101 (5): 644–649. doi:10.1093/jhered/esq061. PMID 20525767.
  12. 1 2 Leigh Anne Clark; Alison N. Starr; Kate L. Tsai; Keith E. Murphy (July 2008). "Genome-wide linkage scan localizes the harlequin locus in the Great Dane to chromosome 9". Gene. 418 (1-2): 49–52. doi:10.1016/j.gene.2008.04.006. PMID 18513894.
  13. ↑ Sophie I. Candille; Christopher B. Kaelin; Bruce M. Cattanach; Bin Yu; Darren A. Thompson; Matthew A. Nix; Julie A. Kerns; Sheila M. Schmutz; Glenn L. Millhauser; Gregory S. Barsh (November 2007). "A β-Defensin Mutation Causes Black Coat Color in Domestic Dogs". Science. 318 (5855): 1418–1423. doi:10.1126/science.1147880. PMC 2906624Freely accessible. PMID 17947548.
  14. ↑ Leigh Anne Clark; Jacquelyn M. Wahl; Christine A. Rees; Keith E. Murphy (January 2006). "Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog". PNAS. 103 (5): 1376–1381. doi:10.1073/pnas.0506940103. ISSN 0273-1134. PMC 1360527Freely accessible. PMID 16407134.
  15. 1 2 3 Sheila M. Schmutz; Tom G. Berryere; Dayna L. Dreger (June 2009). "MITF and White Spotting in Dogs: A Population Study". Journal of Heredity. 100 (Supplement 1): 566–574. doi:10.1093/jhered/esp029.
  16. ↑ Winge, Ojvind (1950). Inheritance in Dogs: With Special Reference to the Hunting Breeds. Catherine Roberts (translator). Ithaca, N.Y.: Comstock Publishing. p. 194.
  17. 1 2 Little, Clarence Cook (1957). The Inheritance of Coat Color in Dogs. New York: Comstock Publishing. p. 194. ISBN 0-87605-621-4.
  18. ↑ Karlsson E. K.; Baranowska I.; Wade C. M.; Salmon Hillbertz N. H.; Zody M. C.; Anderson N.; Biagi T. M.; Patterson N.; Pielberg G. R.; Kulbokas E. J. III; Comstock K. E.; Keller E. T.; Mesirov J. P.; von Euler H.; Kämpe O.; Hedhammar A.; Lander E. S.; Andersson G.; Andersson L.; Lindblad-Toh K. (November 2007). "Efficient mapping of mendelian traits in dogs through genome-wide association". Nature Genetics. 39 (11): 1304–1306. doi:10.1038/ng.2007.10. PMID 17906626.
  19. 1 2 3 Edward J. Cargill1, Thomas R. Famula, Robert D. Schnabel, George M. Strain & Keith E. Murphy (July 2005). "The color of a Dalmatian's spots: Linkage evidence to support the TYRP1 gene". BMC Veterinary Research. 1 (1): 1. doi:10.1186/1746-6148-1-1. ISBN 1-74661-481-1. PMC 1192828Freely accessible. PMID 16045797.
  20. ↑ Why white dogs are white Uppsala University 2014
  21. ↑ Baranowska Körberg, Izabella; Sundström, Elisabeth; Meadows, Jennifer R. S.; Rosengren Pielberg, Gerli; Gustafson, Ulla; Hedhammar, Åke; Karlsson, Elinor K.; Seddon, Jennifer; Söderberg, Arne; Vilà, Carles; Zhang, Xiaolan; Åkesson, Mikael; Lindblad-Toh, Kerstin; Andersson, Göran; Andersson, Leif (2014). "A Simple Repeat Polymorphism in the MITF-M Promoter is a Key Regulator of White Spotting in Dogs". PLoS ONE. 9 (8): e104363. doi:10.1371/journal.pone.0104363. PMID 25116146.
  22. ↑ Sheila M. Schmutz (December 27, 2008). "Coat Color Alleles in Dogs". Retrieved September 12, 2010.
  23. ↑ Pamela A. Davol (January 29, 2001). "B/b, E/e, and Beyond: A Detailed Examination of Coat Color Genetics in the Labrador Retriever". Retrieved September 11, 2010.
  24. ↑ D. J. E. Housley; P. J. Venta (August 2006). "The long and the short of it: evidence that FGF5 is a major determinant of canine 'hair'-itability". Animal Genetics. 37 (4): 309–315. doi:10.1111/j.1365-2052.2006.01448.x. PMID 16879338.
  25. ↑ Droegemueller C, Karlsson EK, Hytšnen MK, Perloski M, Dolf G, Sainio K, Lohi H, Lindblad-Toh K, Leeb T. (2008) A mutation in hairless dogs implicates FOXI3 in ectodermal development. Science. 321:1462.
  26. ↑ "Vet Gen". Veterinary Genetic Services. 2010. Retrieved September 12, 2010.
  27. ↑ "Breeders Assistant". Premier Pedigree Software. 2009. Retrieved September 12, 2010.
  28. ↑ Evans, Howard E.; de Lahunta, Alexander (August 7, 2013). Miller's Anatomy of the Dog (Fourth ed.). Saunders. pp. 71–73. ISBN 978-1437708127.
  29. ↑ Grady, Denise (February 5, 1997). "Nonallergenic Dog? Not Really". New York Times. Retrieved April 3, 2011.
  30. ↑ Heutelbeck AR, Schulz T, Bergmann K, Hallier E (Jan 2008). "Environmental Exposure to Allergens of Different Dog Breeds and Relevance in Allergological Diagnostics". Journal of Toxicology and Environmental Health, Part A. 71 (11-12): 751–8. doi:10.1080/15287390801985513. PMID 18569573.

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