The following quotations are from The Inheritance of Coat Color in Dogs by Clarence C. Little. This is the seminal work on canine coat inheritance and even with far more advanced techniques today, it has stood the test of time with only minor modifications .
1. Like other laboratory mammals dogs appear to have two major types of pigment in their coats One of these is yellow, the other dark (brown or black). The color varieties of dogs have to be formed by various genes controlling the amount, extent, and distribution of these pigments, both individually, in combination, or in competition with one another. Page 21
2. A large number of inherited or transmitted influences which affect the degree of development or expression of the Mendelian genes can be identified.. The type of minor influence is difficult or as yet impossible to analyze. Page 17
3. In the ordinary pair of Mendelian units the one of the pair which masks or conceals the other is called dominant, and the one which is masked, or concealed , recessive.
It is important to recognize and to remember that such masking or concealment (dominance) is often imperfect or incomplete . When this is the case, an animal possessing the two members of a gene pair shows visible and simultaneous development of characteristics dependent upon each of them. Page 16
4. Locus E. This is a difficult group of alleles to define and to understand because of the following complications: (1) there is considerable variation in the expression of , and in interrelations between, the E and the e(br) alleles; (2) the interrelationships existing between coat colors produced by the A series and the E serious of alleles are varied and at times confusing to identification of color types. It will be well, therefore, to consider first those cases in which the visible influence of genes in the E Locus is relatively simple and then take up the more complex examples. Page 49 ( My note: IF it is confusing to a trained genetics scientist, imagine the confusion to lay people such as ourselves.)
e— red-yellow pigmentation. Dogs which are ee in formula exhibit a wide range of pigment quality and depth. They may be a deep rich mahogany as in Irish Setters, an intermediate red-fawn as in Golden Retrievers, or a lemon-orange as in Pointers or English Setters. Page 49.
5. The C series. There appear to be four well recognized alleles in this series. By far the most frequent is C, the gene for full depth of pigmentation….The second member of the series is c(ch) or chinchilla. This gene has a distinctly greater effect in reducing the red-yellow pigment than it does on black pigment. Page 23-24
6. In the individual hairs of chinchilla animals pigment is reduced by the formation of both fewer and smaller pigment granules. Red or yellow is affected before and more extensively than black or brown. In some cases the yellow or red areas are light cream-colored or actually white in appearance because practically all of the granules are absent. The c(ch) gene has little or no visible influence in solid –colored black dogs and it is quite possible that a number of black breeds may really be c(ch)c(ch). Page 44
7. First, most Chows are A(s ) (solid colored)…. Second both kinds of red ( a(y ) (sable) and e,( failure to form dark coat pigment) are found in the breed. Third, true blue dilution ( d) forms the blue and some (if not all) of the cinnamon varieties. Pale colors may also be the result of the c(ch) gene. This would explain the very light creams, the cream-tipped whites, the occasional pure whites and probably the obscure andnot yet analyzed variety :silver grey”. Page 182
Chows have the following genes:
A(s) B C D E g m S t
a(y) c(ch) d e
8. The D-d pair. Dogs with the D gene are called “intensely” or “densely” pigmented. Most dogs fall into this group. The gene d produces Maltese or blue dilution most clearly recognized in short haired dogs, such as blue Great Danes, blue Greyhounds or blue Dobermans. It is also found I Chow Chows…..
The following information is taken from the web pages of Dr. Sheila Schmutz, a professor at the University of Saskatchewan in Saskatchewan, Canada. She is probably the best known of dog color researchers in North America. ( http://homepage.usask.ca/~schmutz/dogcolors.html).
It is recommended that you read her comments under Locus E (red) and red and her comments under white. Unfortunately, it does not appear that research into the cream and the white colors is very advanced at this time.
From her work on Poodles:
“ E Locus
“There are two genetic mechanism by which dogs can be reddish in coat color. The first one is inherited as a recessive, “e/e” at the E locus which is the MCi1R gene. This is the yellow of Labrador Retreivers and also the red of Irish Setters, so the shade can vary tremendously. “e/e” dogs are clear red without a single black hair or even a whisker.”
PLEASE NOTE: At least in Poodles, white whiskers cannot be used to determine if a Poodle is cream or red.
“”The other form of red is “fawn red” called “sable” in a few breeds of dogs such as Shetland Sheep Dogs. This fawn red is caused by the dominant allele “a(y)” at the agouti or A locus. This form of red also occurs in the Poodle. Some dogs have black whiskers or small black hairs intermingled in their coat, but not all with this genotype have black hairs.”
PLEASE NOTE: Little states that both the ay allele and the e alleles are found in Chows. The ay allele may explain why some red Chows have some black sabling in the coat. We do not know if both ay Chows and ee chows can both produce cream.
From her study of Japanese Chin:
“The major question being asked is do both “e/e” clear red and “a(y)” – sable red occur in Japanese Chin? Therefore the first DNA test run was to detect “e/e”
Lilly (name of dog tested) tested E/e which means her reddish color is of the sable type caused by an a(y) allele. Her owner say she has a few black hairs intermingled amongst her red ones, which Is another typical feature of sable red dogs.
Elmo (name of dog tested) is considered lemon whereas YaYa on the right (another dog tested) is considered red. Both tested “e/e” or clear red. The difference in shade is caused by another gene.”
Sheila has more information under the Chins and the Poodles and I would encourage you to go to her web site and look at the Poodles and the Japanese Chin
So from this we know that deep red, pale lemon and cream chows can all test ee at the E locus.
For those of you who wish to have a better understanding of the various genetic loci that affect color I would refer you to the following web site: http://www.luckyhit.net/coatcolo.htm
This web site has the most concise, current and easily understood explanation of color genetics that I have found. Pay particular attention to Loci A, B C, D and E.
Anita Meulstee of Lelystad, the Netherlands has a website that explains in greater detail Chow Coat Color and has graciously agreed to share this data with the Breed Standard Committee.
The page to read is here
additional pages are here:
The loci for color in the Chow Chow breed
Possible color outcomes in Chow Chow breeding
and the color series begins here.
Due to the length of this page the additional examples of red-appearing chows with flesh colored noses appear on this new page.
Carmen Blankenship, Chair of the Breed Standard Committee.