In schipperkes, color is determined on six loci. In the field of genetics, locus (singular) or loci (plural), is the specific location or position of a gene, the DNA sequence, on a chromosome. Most loci are identified by a letter of the alphabet, but loci have more specific names as well. It may get confusing after a while because unless you create your own chart, you might think several loci are in discussion when only one is, or vice versa. Dogs, as well as people, inherit a one set of genes from their father and one from their mother. For every gene or every locus, there will be two genes that come into play. Typically, one type of gene will be expressed over another; these are called dominant. Dominant genes are designated by a capital letter, whereas a matching recessive gene is designated by a lowercase letter. The chart below lists the name designations for the genes involved with color.
While the above chart might look confusing, it is just about the names given to the various loci. Some of the names describe what color they affect. It’s important to understand that all dogs have all of these loci; the question is, which genes on each locus do they have?
At this point I would like describe each locus -- what they are, what they do, and, as best as I am able, cover why they do what they do. This should help you gain a real understanding of what is happening, color-wise, in schipperkes.
THE E-LOCUS I am starting with the E-locus, because regardless of your dog’s color, this is where your understanding should begin. The E-locus doesn’t make a dog all black; it simply determines if there will be any black in your dog’s coat. This-locus controls the production of the black pigment called eumelanin. The original gene on this-locus was the “E” gene; however, a mutation in the gene produced the recessive “e” gene which causes the dog to produce only phaeomelanin -- “a reddish or yellowish brown animal pigment related to melanin and common in animals of arid areas” -- turning what should have been eumelanin in the coat to phaeomelanin. Thus, an “E” gene produces black pigment, and “e” produces a reddish or yellowish pigment. Now, as when you were kids and discovered it was easy to cover a yellow crayon mark with a black one, but not the other way around, if a dog has a copy of each gene (Ee), the black or darker pigment will win because “E” is dominant over “e”. Another modifer which can occur in the Schipperke breed is the “m” mask gene. This creates a black mask on a black dog which is only really seen through, perhaps, better pigment around the eyes and nose.
If your schipperke is “ee” then it is a cream schipperke. This color ranges from white, or nearly white, all the way to a rich, reddish fawn. Pigment on the nose can also range from a black to a brown to a yellow nose. People have used color terms to describe this color as cream, apricot, gold, fawn, red, and white. If your dog carries at least one E gene (EE or Ee), then you need to understand the K gene.
THE K-LOCUS
It is important to note that in order for the K-locus to matter, the dog MUST carry one E. A recessive “ee” schipperke will be a cream schipperke, regardless of what genes are found on the K-locus. While the E-locus determines if there will be black pigment, the “K” locus determines where the black pigment will be on the dog. There are three known alleles1 on the K-locus -- KB (dominant black), k(y) Agouti gene, and k(br) brindling gene. It would appear that the original gene was the k(y) gene. This gene allows the A or Agouti gene to express and the alternative color will be solid. (In other words, this could result in a black and tan schipperke). Sometimes this gene is represented as a “k”, or N, (which represents Normal) or possibly not applicable. This gene mutated in two different directions, both of which are dominant to the original gene. The first way is k(br), which also allows the Agouti gene to express itself, but the other color will contain brindle markings, and, to my knowledge, is not found in schipperkes. The second way is K (or KB). Instead of allowing the Agouti gene to express, the KB gene will flood the dog with black pigment, resulting in an all black dog (or, sometimes a mostly black dog.) Understanding which of these genes are dominant is easy if you remember the lesson of the black and yellow crayons: KB is the blackest and most dominant, k(br) brindle contains black markings in the tan, and thus is more dominant to the last gene, k(y), which has the least amount of blackening.
So, as long as your dog has one K or dominant black gene, you will get black puppies, and the Agouti gene will not come into play at all.
THE A-LOCUS OR AGOUTI GENE
The Agouti gene determines if a dog’s coat is banded or a solid color. The first thing schipperke breeders should note is that in order for the Agouti gene to matter, the dog in question MUST be NN or k(t)k(t). There are currently four known alleles on the A-locus: a(y), a(w), a(t), and a. The allele a(y) produces a sable or fawn dog, such as a collie coat; however, I do not believe that this gene is found in schipperkes. Our reds and creams are produced on the E-gene. The a(w) allele produces a “wild sable” color in which the hairs switch pigmentation from black to reddish or fawn (such as German Shepherds or wolves). The a(t) allele produces what we call the “black and tan” color pattern in schipperkes, and the last gene is “a,” or a recessive black. It appears that on the A-locus we must throw our crayons away as the darkest color is the least dominant! My personal theory is that we have only the last two alleles in the schipperke breed (black and tan and recessive black), and we likely have a high number of a recessive black genes. My reasoning is that over the years, the black and tans were placed as pets (one hopes), while recessive blacks were kept as a normal black schipperke.
If you have a black schipperke, test the K-locus, and your dog is determined as NN and black, you know the A-gene is” aa,” or recessive black. While this may be a good color for showing, you need to understand that the recessive black is recessive to every other allele on the A-gene which means your dog will possibly produce a black and tan puppy if bred to another dog carrying the Agouti gene. This is why I believe it is much easier to test your dog on the K-locus and strive for schipperkes that are double dominant black (KK). Do not worry what is, or is not, found on the A-gene.
I hope I have illustrated that Loci E, K, and A must be seen as steps - 1. E, 2. K, 3. A. Start with E, move to K, and then go to A. The other three genes that I have researched and know can be found in the breed are B, D, and S, and at this point we move away from our 1, 2, 3 pattern of steps.
THE B-LOCUS
The B-locus is: “TYRP1, or tyrosinase-related protein 1, is a protein that plays a role in the synthesis of the pigment eumelanin. In the dominant form of this gene, the “B” allele, normal eumelanin is produced in the coat making the dog’s coat appear black in color rather than chocolate. A mutation in the TYRP1 gene can occur causing a change in function which dilutes the black color pigment to a brown
color.” Synthesis means the “combination or composition,” so this gene determines how the black pigment itself is built in the dog’s genetic code. The original gene creates a black pigment and, hopefully, a black dog. The mutation is referred to as “b”, and it turns all of the black pigment in a dog to a chocolate, liver or possibly red color. This means you will get a solid brown dog with a brown nose, brown lip pigment, etc. This is why a brown schipperke is always “self-colored” (meaning the pigment matches the coat color). Brown schipperkes exist today and were mentioned in the Chasse et Peche in the 1800’s. The B-locus MUST have an E allele in order to express itself which means if your dog is “ee” it will be a cream dog, even if the dog is also “bb”. Interestingly, in this case, the dog will have a yellow or brown nose! To review, the E connects in one direction to the K and the A-locus and in another direction to the B allele. This is why we needed to start with “E” as it makes a center point in understanding how the others will work.
THE D-LOCUS
Now we will move on to the D-locus which is the Dilute gene. This gene has been defined as “the MLPH gene codes for a protein called melanophilin, which is responsible for transporting and fixing melanin-containing cells.” In other words, it is responsible for the proper distribution of color. The mutation on this gene produced what is labeled the “d” allele, and when a dog carries two copies of this allele (dd) then the color will be distributed, but not properly, and the resulting color will be diluted. This gene is a sort of “wild card,” which means it can affect any color combination. This means you can have a dilute black (grey or blue), dilute black and tan, dilute cream, dilute chocolate, etc.
THE S-LOCUS
The last locus is the S gene. I know the least about the S-locus, and I am only including it because some lines have produced small amounts of white on some puppies. There is a test for the S-locus, but I am not sure it will be effective in the schipperke breed, as it states that “dog breeds with white spotting patterns can be affected by additional mutations in MITF and or other genes that affect coat color deletion and distribution. For example, the Irish spotting pattern seen in many breeds of dogs (such as collies) is not caused by this mutation.” I think it is very likely that schipperkes are affected by Irish spotting. The only way to be entirely sure about this would be to test a large number of schipperkes, or tes those dogs that actually have white spots. Unfortunately, such testing would get very expensive very quickly. What this means is that there is a good chance testing for the S-locus is nothing but a waste of money for schipperke breeders. We have been through the six loci so it is natural to ask: What colors are in schipperkes? AKC lists the following colors: black, apricot, black and tan, blue, chocolate, cream, fawn, grey, red and white. Apricot, cream, fawn, red, and possibly white are likely to be variations of the same color (ee). Any of these colors could be easily affected by the “dd” (dilute) combination; a cream becomes white, red becomes fawn, etc. Blue and grey are also the same color. This reduces the color variations I have been able to find down to five: black, black and tan, cream, blue, and brown. Please understand, though, that there are also several theoretical colors which the breed could be if certain colors were crossed enough: lilac (dilute brown), chocolate and tan, blue and cream and lilac and cream.
Are you still confused? This chart might help:
The Locus A-test is not included here because if you are trying to produce a black dog, testing for this gene is not useful. What do health results mean then? * EE: won’t throw cream, could throw black and tan, chocolate or blue. * KK: won’t throw black and tan, could throw cream, chocolate or blue. * BB: won’t throw chocolate, could throw cream, black and tan, and blue. * DD: won’t throw blue, could throw cream, chocolate, or black and tan.
A TRUE double dominant black schipperke would need to be all of the above: EE, KK, BB, and DD. So, you tested some dogs, and you are surprised - you carry for color! What should you do? I wouldn’t necessarily test breed stock unless there is a reason to believe that your dog may carry for color, or you are planning on breeding a dog to another that carries for color. You might not even choose to then: we breed and show black schipperkes; if we produce a colored schipperke in a litter, how is that different than risking a bad bite or missing testicles? It is a health issue, and the only scary part about it is making sure your colored puppies get true pet homes and not secret breeding homes. However, if you have a lot of carriers in your kennel, or you suspect you do, color testing is most useful when you will be choosing between two (or more) puppies.
If you have two girls who are equally lovely, knowing one will never throw the color you are concerned about might tip the balance in her favor. It may also make a greater difference if you are deciding whether to keep a nice male. After all, our boys can be used far more often than our girls. Having a boy who does not carry color would be far more useful than having one that does. What I would NOT do is use these color tests as a means to “clean out your kennel.” Our breed has taken enough hits over the years that I would never use such a test to reduce our gene pool yet further. Hence, choosing between siblings is always going to be your best use for such a test.
Should you decide to test your dogs, it is very, very important NOT TO take short cuts. Follow the procedure on the next page carefully.
A lot of other genes may come into play in the breed, which either exist untested, or have not yet been discovered. This article is intended to help breeders understand the basics of color genetics and how these genes apply specifically to schipperkes. Without breed-wide testing, saying an allele does not exist in the breed is merely a theory. Indeed, we could test 100 dogs and not find an allele and yet it might still exist in the breed. Saying for sure how a dog has inherited a color is at best an educated guess. There are several testing labs you can use, and I included a chart to compare prices based on what you are looking for.
I would also like to make a further note here: if you are testing A-locus, please understand that most places you are either testing for whether something is or isn’t there. If you test through Animal Genetics, E, B, and D are fairly straightforward. If you are testing the K-locus, the lab will be testing for whether your dog has one copy of the dominant black gene, two, or none. An “n” might better denote “not there” than “normal”. If you do choose to test the A-locus, you must make sure that they are testing for at least “at” and “a”, and not just the presence of one or the other. For instance, if a dog comes back as “ay/at”, this may mean that at least one copy of one of these genes may be present. Since I do not believe schipperkes carry for “ay”, this most likely means you know they carry at least one at gene. If you choose to test the A-locus, you really need to know if they have two copies or one copy of the “at” gene or the “a” gene. Whatever you choose to do regarding your dogs, if you plan to spend the money testing, it is worth taking the time to understand what has been written here and make sure you get your money’s worth.