THE PALETTE OF COLOR AND PATTERN - GENETIC LOCI

Color and pattern are produced by many loci working together. The alleles within the locus are listed from most dominant to least dominant. Colors and patterns that are disqualified by the breed standard are highlighted in red.

A Locus - How Pigment is Distributed On the Dog's Hair Shaft and Body

A- Dominant self color (The dog's pigment is uniform on the hair shaft - Black Lab, self colored Aussie)

a^y - Sable (The hair shaft is light with black or liver tipping - Rough collie)

a^s - Saddleback pattern (A saddle of pigment on a tan dog -German shepherd, Airedale, rare in Aussies)

a^t - Tan point pattern (The dog has tan pigment or "points" on the legs, muzzle, eye spots, under the tail, and the front of the shoulder - Dobe, Rottie, Aussie)

 

B Locus - Pigment Color

B - Black

b - red (also called liver or chocolate)

C Locus - Pigment Development

C - Normal pigment development

c^ch - Chinchilla allele - Reduces red and yellow pigment, black unaffected ("White" tiger, some terriers)

c^a - Albino (Complete lack of pigment in skin and eyes-rare in dogs in general)

D Locus - Dilution of pigment

D - Normal pigment distribution

d - Pigment is uniformly diluted so that black becomes uniform blue, liver becomes Isabella (Dobes, Weimaraners) Also called "Maltese Dilution". Does not affect tan points. This is one of the most common mismarks in Aussies.

E Locus - Pigment Restriction/Extension, a very diverse set of alleles

E - Full extension of pigment throughout the hair shaft (Most Aussies are EE).

E^M - Hyperextension mask - black or liver mask on muzzle, displacing tan points on muzzle if they're present (Aussie, German shepherd, Dane, Pug, Dogue de Bordeaux). In merles the mask can be merle or solid depending on how the merle pattern falls.

e^br - Brindle - tiger stripes of black and yellow or liver and yellow (Rare in purebred Aussies but does occur in working lines). When a^t is present, brindle stripes are limited to the tan point areas. NOTE: Brindle is now known not to be in the E series, but its exact location is unknown.

e - Restriction of black and liver pigment to nose leather and eye rims, none in coat. (Yellow Lab, Golden retriever, Irish setter) Another common mismark in Aussies, sometimes called "Palomino or blond" Aussie.

H Locus - Harlequin modifier - This gene acts upon merle but remains unseen in non merles

H - Harlequin (Sometimes called "tweed" in Aussies) - causes different degrees of lightness in merled areas. Some specimens have 4 or more distinctly different shades of blue and gray. In Danes the merled areas are white. This gene's allowability in Aussies is controversial and somewhat dependent on whether it produces any white lacy areas on the individual being judged. (Danes, Aussies)

h- No modification of normal merle pattern (Aussies, Rough & smooth collies, Dachshunds)

 

K Locus - Suppresses the presence of tan point pattern when present in dominant form. Once mistakenly put in the A series as the most recessive.

K - Suppresses tan point pattern in a^t a^t dogs.

k - Tan point pattern allowed to show

M Locus - Merle (A pattern of pigment reduction in the eyes and skin)

M - Merle (In a single dose, M produces patches of blue on a black dog or champagne on a liver dog. In a double dose, much of the body's pigment is lost and often the hearing as well - Aussies, collies, Border collies, Shelties, Dachshunds)

m- Non merled or "normal" allele (No merle pattern - Aussies, collies, Border collies, all breeds in which merling does not occur)

S Locus - Various patterns of white spotting

S - Solid color (No white spotting pattern - Labs, self colored Aussies, Dobes, Irish setters)

s^i - Irish spotting pattern (Typical "Lassie" markings - Rough collies, most Aussies, Shelties)

s^p - Piebald spotting pattern (Non symmetrical random white areas - Beagles, Foxhounds, Caanan dog, some Aussies) Also called "Pattern white" in Aussies.

s^w - Extreme white spotting pattern (Most or all of the dog is white - Pyrenes, Samoyed, Kuvaz, few Aussies). Color headed white may be caused by modifying genes acting on this extreme white gene.

NOTE: Some of these alleles at the S locus may have incomplete or codominance. A dog that is (s^i s^p) may show both patterns simultaneously, for example.

T Locus - Ticking (Spots or flecks of color in white areas where "true" color shows through smudges on the white areas

T - Ticking (Dalmations, Border collies, Aussies)

t - No ticking (White areas are plain white - Collies, Aussies, Foxhounds)

© 2007 Lisa McDonald Feedback