Coat (dog)


Coat (dog)
Close up of a greyhound's short-haired single coat.

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 coarser topcoat, or a single coat, which lacks an undercoat. 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.

Contents

Colours, patterns, lengths & textures

Newfoundland lying next to its combed-out seasonal undercoat.

There is a greater variety of coat colours, 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). Coat colours 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).[1] Research has found that tameness brings associated physical changes, including coat colouring and patterning.[2]

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 coloured 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 in to different backgrounds when viewed from above and below) resulting in differing colouration.[3]

Genetic basis of colour & pattern

Modern breeds of dog exhibit a diverse range of coat colourings, patterns, lengths and textures. In recent years, the understanding of the genetic basis for coat colouring and patterning[4] and coat length and texturing[5] has increased significantly.

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

  • aw = Wild-type agouti (cream to red hair with black tips)
  • Ay = Fawn (cream to red hair with darker tips) or sable (solid black hairs interspersed amongst lighter reddish hairs)
  • As = Saddling
  • at = Tan points; Tricolours
  • a = Recessive black (inhibition of phaeomelanin)

Most texts suggest that the dominance hierarchy for the A locus alleles appears to be as follows: Ay > As > 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.[6] This means, for example, that As may be incompletely dominant over at.

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 - bs, bd and bc)

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.[7]

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:

  • E = No mask, animal expresses eumelanin (coat will be black or brown)
  • EG = Grizzle (dark overlay covering the top and sides of the body, head and tail, and the outside of the limbs)
  • Em = Mask, animal expresses eumelanin (coat will be black or brown)
  • 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: Em > EG > E > e. The Grizzle allele is specific to Salukis and Afghan Hounds, the latter in which it is referred to as "Domino". The expression of EG is dependant upon the animal being homozygous for at and not possessing Em or KB.[8] 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 isolcated the gene at the H locus, but the traits associated with it have been mapped to chromosome 9.[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.[9] 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 colouring pattern of an animal's coat.[10] There are three known alleles that occur at the K locus:

  • KB = Solid colouring (does not mean than white markings can not appear)
  • kbr = Brindle
  • ky = 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: KB > kbr > ky. The colouring 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. 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 coloured and white hairs and other patches of solid colour). 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.[11]

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.[12] There is disagreement as to the number of alleles that occur at the S locus, with researchers postulating either two[13] or four[14] alleles. The four alleles postulated are:

  • S = Solid colour (small areas of white may appear on chest, toes or tail tip)
  • si = Irish-spotting (white on muzzle, forehead, feet, legs, chest and tail)
  • sp = Pie-bald spotting (large areas of white)
  • sw = 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 sp)[12] and other research suggesting the possible existence of a third allele (si).[15] 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.[12] 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.[16]

Postulated colour & pattern loci

There are at least five additional theoretical loci thought to be associated with coat colour in dogs. DNA studies are yet to confirm the existence of these genes or alleles but their existence is theorised based on breeding data:[17]

C (coloured) 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 colour (animal expresses phaeomelanin)
  • cch = Chinchilla (partial inhibition of phaeomelanin resulting in decreased red pigment)
  • ce = Extreme dilution (inhibition of phaeomelanin resulting in extremely reduced red pigment)
  • cb/cp = Blue-eyed albino/Platinum (almost total inhibition of phaeomelanin resulting in near albino appearance)
  • ca = 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.[14] 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.[18]

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.[16]

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 intese 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 & 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.[5]

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.[19] There are two known alleles that occur at the L locus:

  • L = Short coat
  • l = Long coat

L is dominant to l.

The W (wired) locus

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).[5] 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.[5]

The R (curl) Locus[note 1]

The alleles at the R locus (the keratin-71 gene or KRT71) determine whether an animal's coat is straight or curly.[5] 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 seven different phenotypes:[5]

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. 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 one or more dominant alleles, one or more of which is homozygous lethal.[17]

Genetic testing & phenotype prediction

In recent years genetic testing for the alleles of some genes has become available[20] Software is also available to assist breeders in determining the likely outcome of matings.[21]

Nomenclature of colours & patterns

Colours

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

Chesapeakebayretriever01-l.jpg
Brown Chesapeake Bay Retriever
AustrKelpieChocolate wb.jpg
Dark chocolate Australian Kelpie
Brown and its variants, including mahogany, midtone brown, gray-brown, blackish brown; the Chesapeake Bay Retriever, whose colour "must be as nearly that of its working surroundings as possible", also uses the terms sedge and deadgrass. Also includes liver or chocolate, a dark brown.
Seter irlandzki profil 5o899.jpg
Red Irish Setter
Chowchow.jpg

Red Chow Chow
Red—reminiscent of reddish woods such as cherry or mahogany—and its variants, including chestnut, tawny, orange, roan, rust, red-gold, reddish brown, bronze, cinnamon, tan, and ruby.
Apricot Poodle GoldenRetrDark4 wb.jpg
Dark Golden Retriever
Gold Rich reddish-yellow, as in a Golden Retriever, and its variants, including yellow-gold, lion-coloured, fawn, apricot, wheaten (pale yellow or fawn, like the colour of ripe wheat), tawny, straw, yellow-red, mustard, sandy, honey.
MuttShepherdRetriever 72.jpg
Yellow mixed-breed dog
YellowLabradorLooking.jpg
Yellow Labrador Retriever
Yellow—yellowish-gold tan, as in a yellow Labrador Retriever—and its variants, including blond and lemon. Lemon is a very pale yellow or wheaten colour which is not present at birth (the puppies are born white) but gradually becomes apparent, usually during the first six months of life.
FrenchBulldog.jpg
Cream French Bulldog
Cream: Sometimes it's hard to define the line between pale yellow and cream. Depending on the breed and individual, cream ranges from white through ivory and blond, often occurring with or beneath lemon, yellow, and sable.
Galibalticstorm.JPG
Black Newfoundland
Black Labrador Retriever portrait.jpg
Black Labrador Retriever
Black: Usually pure black but sometimes grizzled, particularly as dogs age and develop white hairs, usually around the muzzle.

Kerry Blue Terriers
Australian Shepherd 600.jpg
Blue merle Australian Shepherd
Blue: Not the rainbow's blue but rather a dark metallic gray, often as a blue merle or speckled (with black). Kerry Blue Terriers, Australian Silky Terriers, Australian Shepherds, Bearded Collies, Great Danes, and Neapolitan Mastiffs are among many breeds that come in blue.
Weimaraner wb.jpg
Silver gray Weimaraner
Miniature Schnauzer 2.jpg
Salt and pepper gray Miniature Schnauzer
Gray—sometimes also called blue—and its variants, including pale to dark gray, silver, pepper, grizzle, slate, blue-black gray, black and silver, steel, lavender, silver-fawn.
American Eskimo Dog.jpg
White American Eskimo Dog
Bichon Frise 600.jpg
White Bichon Frisé
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-coloured 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.

Australien Kelpie.jpg
Liver and tan Australian Kelpie
BTCoonhnd.jpg
Black and Tan Coonhound
Black and tan, liver and tan, blue and tan: Coat has both colours but in clearly defined and separated areas, usually with the darker colour 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.
Border Collie 600.jpg
Black and white Border Collie
CavalierKgChas2 wb.jpg.jpg
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 colour 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.
EntlebucherBall2 wb.jpg
Black tricolour Entlebucher Mountain Dog
Beagle 600.jpg
Tricolour Beagle
Tricolour: Three clearly defined colours, 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. Tricolour can also refer to a dog whose coat is patched, usually two colours (such as black and tan) on a white background.
Australian Shepherd 600.jpg
Blue merle tricolour Australian Shepherd
CatahoulaRedWhitePair wb.jpg
Red merle Catahoula Leopard Dogs
Merle: Marbled coat with darker patches and spots of the specified colour. Merle is referred to as "Dapple" with Dachshunds.
Tuxedomix.jpg
Tuxedo mixed-breed dog.
Red tuxedo2.jpg
Tuxedo mixed-breed
Tuxedo: Solid (usually black) with a white patch (shirt front) on the chest and chin, and white on some or all of the feet (spats.) Common colouration in Labrador mixes that may stem from the St. John's Water Dog ancestral breed.
Great-Dane wo Background.jpg
Harlequin Great Dane
Harlequin: "ripped" sploches of black on white. Only the Great Dane exhibits this coat pattern.
Dalmatian b 01.jpg
Spotted Dalmatian
Spotted Most often dark pigmented spots on a light background. The spotting on dalmatians is unique as it involves mutations in at least three different spotting genes.[16]
AustrCattleDogRed wb.jpg
Red-speckled Australian Cattle Dog
GermanShorthPtr wb.jpg
Liver-ticked German Shorthaired Pointer
Flecked, ticked, speckled: also called belton in English Setters
Rio14months.jpg
Orange belton (orange and white speckled) English Setter
AustrCattleDogBlue wb.jpg
Blue speckled Australian Cattle Dog
BostonTerrierBrindleStand w.jpg
Darker brindle and white Boston Terrier
Galgo-Espanol.jpg
Medium brindle Galgo Español
Brindle: A mixture of black with brown, tan, or gold; usually in a "tiger stripe" pattern.
Rambo.jpg
Airedale Terrier with large black saddle
Saddle or blanket: A different colour, usually darker, over the center of the back.
Pomeranian orange sable 600.jpg
Dark orange sable Pomeranian
Shetland sheepdogs.jpg
Lighter sable Shetland Sheepdogs
Sable: Black-tipped hairs; the background colour can be gold to yellow, silver, gray, or tan. The darkness of the coat depends on how much of each hair is black versus the lighter colour.

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 cycle of growing, then dying and being replaced by another follicle. When the follicle dies, the hair is shed (moults). The length of time of the growing and shedding cycle varies by breed, age, and by whether the dog is an inside or outside dog.

Many dogs shed their undercoat each spring and regrow it again as colder weather comes in; this is also referred to as blowing the coat. Many domesticated breeds shed their coat twice a year. In some climates, the topcoat and undercoat might shed continuously in greater and smaller quantities all year.

Hypoallergenic coats

Some breeders claim that Portuguese Water Dogs have hypoallergenic coats.

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.[22] Although poodles and terriers (and mixes of poodles 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..."[23]

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. ^ James Serpell, ed (1995). The Domestic Dog: Its Evolution, Behaviour and Interactions with People. Cambridge, United Kingdom: Cambridge University Press. p. 284. ISBN 0521425379. 
  2. ^ 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. 
  3. ^ 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. 
  4. ^ Schmutz, S. M. & Berryere, T. G. (December 2007). "Genes affecting coat colour and pattern in domestic dogs: a review". Animal Genetics 38 (6): 539–549. doi:10.1111/j.1365-2052.2007.01664.x. PMID 18052939. 
  5. ^ a b c d e f 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 2897713. PMID 19713490. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2897713. 
  6. ^ Julie A. Kerns, J. Newton, Tom G. Berryere, Edward M. Rubin, Jan-Fang Cheng, Sheila M. Schmutz and 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. ISBN 0033500423771. PMID 15520882. 
  7. ^ 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. ISBN 4712156634. PMC 1183202. PMID 15960853. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1183202. 
  8. ^ 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. 
  9. ^ a b 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. 
  10. ^ 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 2906624. PMID 17947548. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2906624. 
  11. ^ 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. ISBN 0506940103. PMC 1360527. PMID 16407134. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1360527. 
  12. ^ a b c Sheila M. Schmutz, Tom G. Berryere & Dayna L. Dreger (June 2009). "MITF and White Spotting in Dogs: A Population Study". Journal of Heredity 100 (Suppliment 1): 566–574. doi:10.1093/jhered/esp029. 
  13. ^ Winge, Ojvind (1950). Inheritance in Dogs: With Special Reference to the Hunting Breeds. Catherine Roberts (translator). Ithaca, N.Y.: Comstock Publishing. p. 194. 
  14. ^ a b Little, Clarence Cook (1957). The Inheritance of Coat Color in Dogs. New York: Comstock Publishing. p. 194. ISBN 0876056214. ISSN B0007DYSH6. 
  15. ^ 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 17968344. 
  16. ^ a b c 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 1746614811. PMC 1192828. PMID 16045797. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1192828. 
  17. ^ a b Sheila M. Schmutz (December 27, 2008). "Coat Color Alleles in Dogs". http://homepage.usask.ca/~schmutz/alleles.html. Retrieved September 12, 2010. 
  18. ^ Pamela A. Davol (January 29, 2001). "B/b, E/e, and Beyond: A Detailed Examination of Coat Color Genetics in the Labrador Retriever". http://www.labbies.com/genetics2.htm. Retrieved September 11, 2010. 
  19. ^ 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. 
  20. ^ "Vet Gen". Veterinary Genetic Services. 2010. http://www.vetgen.com/index.html. Retrieved September 12, 2010. 
  21. ^ "Breeders Assistant". Premier Pedigree Software. 2009. http://www.tenset.co.uk/ba/index.html. Retrieved September 12, 2010. 
  22. ^ Grady, Denise (February 5, 1997). "Nonallergenic Dog? Not Really". New York Times. http://query.nytimes.com/gst/fullpage.html?res=9B07E0D61E3DF936A35751C0A961958260&n=Top/News/Science/Topics/Animals. Retrieved April 3, 2011. 
  23. ^ Heutelbeck ARR, 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. http://www.informaworld.com/smpp/content~content=a793780326~db=all~order=page. 

Additional Reading

  • Cunliffe, Juliette (2004). "Coat Types, Colours and Markings". The Encyclopedia of Dog Breeds. Paragon Publishing. pp. 20–23 and various. ISBN 0752582763. 
  • Fogle, Bruce (2000). "The Breed Section Explained". The New Encyclopedia of the Dog. Dorling Kindersley. p. 83 and various. ISBN 0751304719. 

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Dog anatomy — includes the same internal structures that are in humans. Details of structures vary tremendously from breed to breed, more than in any other animal species, wild or domesticated,[1] as dogs vary from the tiny Chihuahua to the giant Irish… …   Wikipedia

  • Dog coat — can refer to: rug (animal covering), jacket or blanket for a dog coat (dog), dog s fur or hair This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish …   Wikipedia

  • Coat — can refer to any one of the following: Coat, a layer of a certain substance, usually paint. Coat (animal), the natural fur coat of an animal. Coat (clothing), an article of clothing for humans. Coat (dog), the natural fur coat of a dog. Coat of… …   Wikipedia

  • Dog — For other uses, see Dog (disambiguation). Domestic dog Temporal range: 0.015–0 Ma …   Wikipedia

  • Coat (animal) — For other uses, see Coat (disambiguation). Coat, or the nature and quality of a show mammal s pelage, is important to the animal fancy in the judging of the animal, particularly at conformation dog shows, cat shows and horse shows. It may also be …   Wikipedia

  • Dog skin disorders — are among the most common health problems in dogs. Skin disorders in dogs have many causes, and many of the common skin disorders that afflict people have a counterpart in dogs. The condition of dog s skin and coat can also be an important… …   Wikipedia

  • Dog training — is the process of teaching skills or behaviours to a dog. This can include teaching a dog to respond to certain commands, or helping the dog learn coping skills for stressful environments. Dog training often includes operant conditioning,… …   Wikipedia

  • Dog breeding — is the practice of mating selected specimens with the intent to maintain or produce specific qualities and characteristics. A litter of puppies and their mother Dogs reproduce without human interference, so their offsprings characteristics are… …   Wikipedia

  • Coat of arms of Finland — Details Adopted First documented in the 1580s. Current version official since 1978. Esc …   Wikipedia

  • Dog Latin — Dog Latin, Cod Latin, macaronic Latin, or mock Latin refers to the creation of a phrase or jargon in imitation of Latin,[1] often by directly translating English words (or those of other European languages) into Latin without conjugation or… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.