Dog genetics is quite a common topic and many books have been written about it, and you can find a lot of information about genetics on the Internet. But when several years ago I began to be directly interested in genetics of Shih Tzu colors, none of the Shih Tzu breeders, who work with the breed for many years, could give me an answer to my questions. One or two people gave me only some hints where I could look for information on this subject. And I wandered off to look for it on foreign sites, buying books in English abroad. I understand that for many breeders the color of the dog (and directly color genetics) is not an important factor in breeding, of course, more attention should be paid to the health, temperament and anatomy of the dog. But it is possible that color genetics will interest someone too, as it did me at one time. Again, I don’t want to claim that my opinion is the ultimate truth, it’s just my point of view.
Sable
At present there is not a very large number of colors in shih tzu show lines. Shih Tzu can not keep up with the same Chihuahua in this regard. One of the most widespread and popular shih tzu colors is sable. Just dogs of this color prevail in show rings, this very color was one of the main colors, which shih tzu had been cultivated on the territory of the historical homeland of the breed (China).
Golden with and without black mask, golden with white, white-gold, pale, red with black mask, red with white, white-red — all these are genetically sable color. The intensity (brightness) of the coloration, presence or absence of blackness depends on genetic modifiers, but all this is a sable color! Even rare in breed blue color is often a variation of sable color, when abundant black pigment in hair under the influence of external environmental factors (humidity, where the dog lives, food, etc.) changes from bright black to gray. And the born sable puppy becomes blue over time.
The next most frequent color in the breed is black (solid black, black-white, white-black). This coloration is dominant in relation to the sable coloration and is due to the presence of the dominant K gene in the dog. In this case, the black pigment in the puppy’s hair is distributed in such a way that the puppy’s coat is completely colored black. Even so, the dog can be a genetic «sable.»
Black and Tan
A rather rare color in the population is black and tan (black and tan with white). It is also rare because in relation to the above coloration it is recessive. And for a puppy of such color to appear in a litter one should have parents of such color or BOTH of them could be carriers of this color at least. But, of course, the probability of black and tan appearance from two carriers is not so high. In shih tzu pedigrees black hispanic with white color most often is written as «tricolor», but….. In the same way in the pedigree can be called a sable color.
Although, of course, the probability of having a black and tan puppy from two carriers is not great. In shih tzu pedigrees the black and tan with white color most often is written as «tricolor», but ….. In the same way in the pedigree can be named also sable color.
A rather rare color in the population is black and tan (black and tan with white). It is also rare because in relation to the above coloration it is recessive. And for a puppy of such color to appear in a litter one should have parents of such color or BOTH of them could be carriers of this color at least. But, of course, the probability of black and tan appearance from two carriers is not so high. In shih tzu pedigrees black hispanic with white color most often is written as «tricolor», but….. In the same way in the pedigree can be called a sable color. Of course, this is absolutely not correct, because the real tricolor shih tzu and sable color have completely different genotypes! What does a black and tan shih tzu look like? It can be almost a black dog, but some places on the dog’s body will be colored gold or red — points above the eyebrows, cheeks, lower part of the muzzle and neck, a small section of hair near the anus, paws, and lower part of the chest. But… depending on the influence of some modifiers, some of the lightened spots described above may be missing. And very often a black and tan with white shih tzu is mistaken for a black and white dog for the reason that where on hair of a dog there should be characteristic for this color golden or red spots, there are marks (white spots).
I have heard of cases where two golden and white dogs give birth to a black and white puppy. On the one hand, this should not be, since the black color, being dominant over the sable (in the described case white-gold), can appear if at least one of the parents is black (black-white, white-black). In this case we can say either that one of the parents (most likely the daddy) is not the parent of the puppy, or that the puppy is not black-and-white, but a true tricolor (black-painted with white). One can look closely at those areas on a shih tzu coat where there are usually characteristic gold or red spots on the black and tan color. More often than not, some red or gold hair can be found in the area behind the ears and in the anal area.
And other colors
What about other colors? I admit that you have heard of shih tzu in other colors. Many different colors are found in dogs from the «commercial line» in the USA. I must say that American breeders in general are famous for breeding many colors that have never existed before in the breeds. This fate befell all breeds that are more or less popular among buyers in the USA. And, despite the fact that breeders of this direction of breeding call their dogs Shih Tzu, they have only a superficial relation to this breed. And, as a rule, these dogs with show lines are never crossed, but are bred separately. Liver, amber, pure white, tiger, gray, etc. Well, think about it, where all of a sudden in a dog breed for a very short period could appear such an abundance of colors? Such quantity of gene mutations simply is impossible for such short term, if certainly we do not speak about external influence on genes, for example, by means of nuclear reaction. But the USA is not Chernobyl or Fukushima in Japan. So I can only assume that in order to get such a wide range of colors in shih tzu, the Americans mixed the dogs with other breeds. Although, if you look closely, the appearance of shih tzu from commercial lines is different from the appearance of show-breeding dogs. That’s why I can’t consider these colors typical of my favorite breed.
Markings
What about white spots in a dog, you ask? I’m talking about solid colors in almost all cases. No, my friends, white spots on a dark background is not a color, it is a marking. And they are inherited by not very simple scheme, which I will not describe here, so as not to confuse you even more.
Masked
The black mask is most often an «accessory» for golden or red dogs of solid color (see photo above). Well, on the black color you simply will not see it, although genetically this dog may be the owner of a black mask. The gene responsible for the appearance of the black mask is a dominant and present in almost all Shih Tzu lines, even where only white-gold or white-red dogs are born. But look at their muzzle.
You have, I think, noticed that some dogs of this color have a very nice black border that goes into the top of the knot, creating a very striking picture. This is nothing more than the «remnants» of the mask, which is hidden under the white markings on the muzzle.
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again about the genetics of shih tzu color Smiley «wink»
GENERAL RULES OF COLOR INHERITANCE.
Rule 1: two black dogs can produce any color as long as it is inherent in genotype as recessive genes.
Rule 2: two red (deer) dogs with masks (with black noses) cannot produce chocolate, black, blue, purple puppies, because red (deer) dogs do not have the dominant black gene K in their genotype, without which black, chocolate, blue and purple colors are impossible.
Rule 3: two chocolate dogs cannot produce black, blue, red (fawn), cream or isabella puppies, because the genotype of chocolate dogs lacks the black pigment gene B, which is responsible for the presence of this pigment in the dog’s phenotype (mask or black nose in red dogs, completely black hair in black dogs, gray hair in blue dogs).
Rule 4: Two blue, blue and isabella, blue and mauve dogs ONLY produce colors with the double blue gene, i.e. blue, isabella, mauve. Black, chocolate, red, and fawn with a mask or black nose are not possible due to the absence of the dominant D gene in blue, isabella, and purple dogs.
Rule 5: from two dogs with a chocolate pigment it is impossible to get dogs with black or gray (blue) pigment
Rule 6: From two cream dogs you can only get cream puppies (or cream dilute puppies). Two cream diliut dogs can ONLY produce cream diliut puppies.
Rule 7: You cannot get blue or purple puppies from two Isabella dogs. Only an isabella and an isabella dillute can be produced. You can only get an isabella diliut from two isabella diliut dogs.
Rule 8: Two mauve dogs cannot produce blue, isabella, or chocolate puppies. You can only get mauve and isabella dillut.
Rule 9: You cannot get black or any other color with black or gray pigment from a chocolate or purple dog.
Rule 10: It is possible to get cream puppies with grey (blue) or purple pigment from dogs with grey (blue) or purple pigment, which at this stage are registered as cream or cream diliut due to the absence of their own names.
These are a few basic rules to avoid mistakes in breeding at the amateur level. (https://www.facebook.com/groups/670720003050277/80609..)