Usuario:Jcfidy/Taller

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Capa (perro)

Montaje mostrando la variación de la capa del perro.

La capa del perro doméstico (Canis lupus familiaris) se refiere al pelo que cubre su cuerpo. La capa de un perro puede ser una capa doble, compuesta de una capa inferior suave y una capa superior más resistente, o una sola capa, que carece de subpelo.​ Las capas dobles tienen una capa superior, hecha de pelos rígidos para ayudar a repeler el agua y el escudo de la suciedad, y un subpelo que sirve como aislamiento. Los términos pelaje y capa se usan a menudo de forma intercambiable cuando describen el abrigo de perro, sin embargo en general, pelaje, por ejemplo, al igual que el de Terranova y la mayoría de los perros de montaña, se conoce como un abrigo de piel, mientras que una sola capa, al igual que la del caniche, se conoce como un capa.

Colores, patrones, longitudes y texturas

Newfoundland lying next to its combed-out seasonal undercoat.

Hay una mayor variedad de colores de abrigo, patrones, longitudes y texturas que se encuentran en el perro que en relación con el lobo, aunque los perros y los lobos pertenecen a la misma especie (Canis lupus). En diferentes razas se utilizan distintos nombres para los tipos de pelo largo y corto, no hay una nomenclatura estándar para la longitud, los estándares de la raza dan longitudes aceptables por la medición. Los colores de los escudos de los perros no fueron elegidos inicialmente por los humanos, pero probablemente fueron el resultado inadvertido de algún otro proceso de selección (es decir, la selección por la mansedumbre).​ La investigación ha encontrado que la mansedumbre trae cambios físicos asociados.​

Los perros a menudo muestran los restos de contrasombreado, un patrón de camuflaje natural común. El principio básico del contrasombreado es cuando el animal se ilumina desde arriba, las sombras se echarán en el lado ventral del cuerpo. Estas sombras podrían proporcionar un depredador o presa con señales visuales relacionadas con el movimiento del animal. Al ser de color más claro en el lado ventral del cuerpo, un animal puede contrarrestar esto, y por lo tanto engañar al depredador o presa. Una explicación alternativa es que los lados dorsal y ventral de un animal experimentan diferentes presiones de selección (de la necesidad de mezclarse en diferentes fondos cuando se ven desde arriba y abajo) dando lugar a coloración diferente.​

Bases genéticas de color y patrón

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.

Archivo:Cream french bulldog.jpg

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​ and coat length and texturing​ 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:

• a^w = Wild-type agouti (cream to red hair with black tips)
• A^y = Fawn/clear sable (cream to red hair with darker tips) or sable (solid black hairs interspersed amongst lighter reddish hairs)
• a^t = Tanpoint including saddle tan,​​
• a = Recessive black (inhibition of phaeomelanin)

Most texts suggest that the dominance hierarchy for the A locus alleles appears to be as follows: A^y > a^w > a^t > 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.​ This means, for example, that A^y may be incompletely dominant over a^t. 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 = Black
• b = Brown (includes several alleles - b^s, b^d and b^c)

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 = Not Diluted
• d = Diluted (Black becomes grey or blue; brown becomes light tan or "Isabella")

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.​

E (extension) locus

The alleles at the E locus (the melanocortin receptor one 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:

• E^m = Mask, animal expresses eumelanin (coat will be black or brown)
• E^G = Grizzle (dark overlay covering the top and sides of the body, head and tail, and the outside of the limbs)
• E = No mask, animal expresses eumelanin (coat will be black or brown)
• e^h = Sable - dirty red, found in English Cocker Spaniels (dark overlay covering the top and sides of the body, head and tail, and the outside of the limbs)
• e = No mask, animal does not express eumelanin (coat will be red or yellow)

The dominance hierarchy for the E locus alleles appears to be as follows: E^m > E^G > E > e^h > 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 e^h 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 a^t and not possessing E^m or E. The expression of E^G is dependent upon the animal being homozygous for a^t and not possessing E^m or K^B.​ 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 c^a 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.​ 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 = Harlequin
• h = Non-harlequin

H is dominant to h. Breeding data suggests that H is embryonic recessive lethal and that therefore all harlequins are H/h.​ 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.​ There are three known alleles that occur at the K locus:

• K^B = Solid coloring (does not mean that white markings can not appear)
• k^br = Brindle
• k^y = Enables the expression of agouti alleles that require the expression of phaeomelanin

The dominance hierarchy for the K locus alleles appears to be as follows: K^B > k^br > k^y. The coloring of an animal that possesses at least one K^B will be determined by the alleles it possesses at the B and E loci. An animal with one k^br allele and no K^B 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 k^y 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 = Merle (visible in dogs that are not e/e)
• m = Non-merle

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.​

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.​ There is disagreement as to the number of alleles that occur at the S locus, with researchers postulating either two​ or four​ alleles. The four alleles postulated are:

• S = Solid color (small areas of white may appear on chest, toes or tail tip)
• sⁱ = Irish-spotting (white on muzzle, forehead, feet, legs, chest and tail)
• s^p = Pie-bald spotting (large areas of white)
• s^w = Extreme pie-bald spotting (Extremely large areas of white, almost completely white)

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 s^p)​ and other research suggesting the possible existence of a third allele (sⁱ).​ It has been suggested that what appears to be the result of an s^w allele is in fact the result of plus and minus modifiers acting on one of the other alleles.​ 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.​

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.​​

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:​

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:

• C = Full color (animal expresses phaeomelanin)
• c^ch = Chinchilla (partial inhibition of phaeomelanin resulting in decreased red pigment)
• c^e = Extreme dilution (inhibition of phaeomelanin resulting in extremely reduced red pigment)
• c^b/c^p = Blue-eyed albino/Platinum (almost total inhibition of phaeomelanin resulting in near albino appearance)
• c^a = Albino (complete inhibition of phaeomelanin production, resulting in complete inhibition of melanin production)

The C locus in dogs is not well understood and the theorised alleles are based on those present in other species.​ 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.​

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:

• F = Flecked
• f = Not flecked

It is thought that F is dominant to f.​

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:

• G = Premature greying
• g = No premature greying

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:

• I = Intense red, not diluted
• i = Not intense red

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:

• T = Ticked
• t = Not ticked

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.​

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.​ There are two known alleles that occur at the L locus:

• L = Short coat
• l = Long coat

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).​ There are two known alleles that occur at the W locus:

• W = Wire (hair is coarse and facial furnishings present)
• w = Non-wire (hair is not coarse and facial furnishings are not present)

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.​

The R (curl) Locus​

Curly hair.

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

• R = Straight
• r = Curly

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:​

• Hairless (e.g. Chihuahua)
• Short (e.g. Basset Hound)
• Wire (e.g. Australian Terrier)
• Curly-wire (e.g. Airedale Terrier)
• Long (e.g. Golden Retriever)
• Long with furnishings (e.g. Bearded Collie)
• Long and curly (e.g. Irish Water Spaniel)
• Long and curly with furnishings (e.g. Bichon Frisé)

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:

• Australian Silky Terrier
• Bedlington Terrier
• Bichon Frisé
• Maltese
• Poodle
• Skye Terrier
• Soft Coated Wheaten Terrier
• Yorkshire Terrier
• Shih Tzu
• Lhasa Apso
• Coton de tulear
• Tibetan terrier

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.​

Genetic testing and phenotype prediction

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

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.

• 
  Brown Chesapeake Bay Retriever
• 
  Red Australian Kelpie
• 
  Dark and light chocolate Labrador Retrievers

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.

• 
  Red Irish Setter
• 
  Red Chow Chow
• 
  Red Standard Poodle
• 
  Ruby Cavalier King Charles Spaniel
• 
  Red Australian Cattle Dog

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.

• 
  Apricot Poodle
• 
  Dark Golden Retrievers
• 
  Yellow Dachshund
• 
  Yellow Labrador Retriever

Cream

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

• 
  Pale cream Standard Poodle
• 
  Cream French Bulldog
• 
  Cream Akita

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.

• 
  Fawn Pug
• 
  Fawn English Mastiff
• 
  Fawn Belgian Shepherd Malinois
• 
  Fawn Boxer

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.

• 
  Newfoundland
• 
  Black Labrador Retriever

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.

• 
  Blue Neapolitan Mastiff
• 
  Blue mixed-breed dog
• 
  Blue Australian Silky Terrier
• 
  Blue Australian Cattle Dog

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.

• 
  Lighter and darker fawn Weimaraners
• 
  Silver Miniature Schnauzer
• 
  Silver Miniature Poodle
• 
  Isabella/fawn Dobermann

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.

• 
  White American Eskimo Dog
• 
  White Bichon Frisé

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.
Archivo:Tuxedomix.jpg Tuxedo Lab mix.	Archivo:Red tuxedo2.jpg 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.​
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.
Archivo:Rambo the Airedale Terrier.jpg 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.​

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.​ 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..."​

See also

• Cat coat genetics
• Dog grooming
• Equine coat color genetics
• Farm-Fox Experiment
• Hypoallergenic
• List of dog breeds
• Merle (coat color in dogs)
• Dog skin disorders

Additional reading

• Cunliffe, Juliette (2004). «Coat Types, Colors and Markings». The Encyclopedia of Dog Breeds. Paragon Publishing. pp. 20-23 and various. ISBN 0-7525-8276-3. 
• Fogle, Bruce (2000). «The Breed Section Explained». The New Encyclopedia of the Dog. Dorling Kindersley. p. 83 and various. ISBN 0-7513-0471-9. 

External links

• Schmutz, Sheila M. (March 4, 2010). «Dog Coat Color Genetics». University of Saskatchewan. Consultado el September 12, 2010.