Why are Harlequins so Expensive? - An in depth Look at Great Dane Genetics

Once you understand the basics of genetics, its a lot easier to understand what a fellow breeder is trying to communicate. Read more about genetics basics HERE. This article intends to go over both color genes and color traits of Great Danes. There are a lot of genes that can be genetically tested for however there are only a few that breeders typically pay attention to. Keep in mind the common name of a gene or trait are not the same as the scientific name. The letters used to talk about these traits are also commonly accepted by the community but can vary depending on the speaker. For example one genetic testing sight might use the grouping M* to indicate that the dog posses one copy of the merle gene. A different company my show that same dog as Mm indicating that the merle gene is a dominant gene with the capital letter. The letters and words I will use are the ones that I personally prefer but its important to understand genetics in the event that the speaker changes. Not all breeders speak the same way about genes and traits. The terminology may also change as AKC recognizes new colors as registerable. It is important to remember from the previous article that both genes and traits can be carried and passed onto offspring. 

The CBD103 Gene (KB, KBr, Ky) The Sharpie Gene or Dominant Black Gene

The CBD103 Gene is an allelic gene that is represented by the letter K. This gene is sometimes called the dominant black gene. I personally refer to this gene as the “Sharpie gene”. This gene interacts with the ASIP gene(responsible for fawn and points). The K loci impacts if the allele on the A loci will be visible. KB is the most dominant version of this gene. A dog that has a single KB gene will not show anything at the a loci. Dogs that are single KB will be black, blue, chocolate, or lilac as a base color. The K genes least dominant version is listed as Ky with the y being lowercase to indicate its recessive. A dog that is KyKy will show what ever the dog is at the A loci. These dogs will be fawn, or tan point in color. There is however a mutation of the dominant KB alle which is dominant over Ky but recessive to KB and is listed as KBr. KBr at this time is unable to be tested for in a genetic color test. There is scientific data which suggests that this gene mutation exists. Dogs that are speculated to have a KBr Ky combination appear as brindle or brindle point depending on which ASIP alleles they have. Dogs that are speculated to have a KBKBr combination do not show brindle, but may have brindle/brindle point puppies when bred to a dog who is KyKy. 

We do not fully understand how the brindling trait works at this time and can only make educated assumptions based on data. We do not know at this time if the combination of two KBr mutated genes is a possibility since we can not test for the gene. There is some speculation in the scientific community that the KBr KBr genome would present as a solid dog and that one or two mutated copies may actually pass on as not mutated at all. Research is ongoing.

The CBD103 or K gene is not a color on its own and is typically used when discussing polygenic traits such as (fawn, tan point, brindle, and brindle point). A dog who is KBKy or KBrKy may be stated as a dog that carries for fawn or points. A dog who is KBKy may also be stated as being a genetic tan point if the ASIP genes support that claim. It is important to remember that a dog who has one brindle parent may not necessarily carry for brindle. A dog who is a visual fawn or tan point will also not carry for brindle. If you are wanting to reliably produce brindle in your litters your best option would be for at least one of your breeding dogs to show the brindle, or brindle point trait. 

The ASIP Gene (Ay, At) Fawn, Brindle, Tan Point, Brindle point

The ASIP gene is only visible if the “K” gene allows it to be expressed. This gene is also an allelic gene with a hierarchy. There are three options that can be expressed at this loci ay, at, and aw. The ay allele is dominant over the other two with aw being the least dominant. 

Both girls in this photo are genetically brindle. You can see the wide range of variation between the two girls even though they are both KyKBr

If the K gene allows the A gene to be expressed then a dog that has one or two copies of the Ay gene will be fawn or brindle depending on what is expressed at the K gene. Both at and aw are responsible for points. They are not the same and do show up differently on a color test. Most breeders agree that a dog who is awaw will express as a pointed dog where the points are higher up and almost look like a saddle. Breeders who have been around for a long time may refer to this gene as wild sable. The Atat combination is typically called tan point or brindle point if the K gene is brindle. Its important to keep in mind that a dog has to have something at this loci but it may not always be visible. 

For example a dog that carries tan point could be expressed as KBky AyAt a dog may “Carry fawn” depending on the K gene as well. A dog who possess is KBKy atat or KBKB atat is typically referred to as a genetic tan point. While these dogs do not express points they will always pass on one copy of the pointed gene to their off spring. 

D Locus Melanophilin MLPH Dilute

The D locus is responsible for producing diluted colors. Dilute will turn a black base color blue and a chocolate base color lilac or silver. Dilute is a simple recessive gene so in order for a dog to be visually dilute they will need to get a copy of the recessive d gene from each parent. Dilute will impact all colors and patterns. For example you may have blue fawn, lilac brindle, blue harlequin, and so on. 

B Locus Tyrosinase Related Protein 1 (TYRP1) Chocolate

The B locus determines if the dog is a black or a brown base. Brown or chocolate is the recessive version of the gene. Chocolate can impact all other colors. You may have a chocolate harlequin, chocolate fawn, or chocolate brindle. Chocolate is also a recessive gene, so in order for it to be shown on a dog the dog must have 2 copies of the chocolate gene, one from each parent. 

So Locus MITF Pied

The pied gene is speculated to be an incomplete dominant gene but may be a recessive gene. The double SP version of the gene will be a white dog with rounded spots of color. There is speculation that a dog who only has one copy of the SP gene will show as being a mantle. At this time this has not been confirmed so when speaking of pied we would consider it to be a recessive gene where the dog would need to inherit one SP gene from each parent. Pied may also be expressed with any other color and both of the pattern genes. For example you can have a merle pied, or a harl headed pied. It is important to note that the harl headed pied is often mistaken for a double merle dog due to the high amount of white. Pied dogs typically have color on their ears and near their eyes. The color also causes small speckles called ticking similar to the look of a hunting dog. 

M Locus PMEL Merle

Blue brindle merle

The Merle Locus is one of the most important loci to test. Merle is an incomplete dominant gene meaning if the dog has one copy of the gene it will show the merle gene. The super form of the gene or double merle typically has health problems such as cardiovascular issues, increased likelihood of some cancers, increased likelihood to be blind and deaf. The merle gene also comes in lengths. There is a Cryptic (may not visually look merle or may have very few spots) A-typical length (a medium amount of spots) and, Classic merle which looks as you would expect. There is some speculation that a double merle with one merle length being cryptic may not have the issues that the other two lengths have. Until this is proven though we will not be taking the risk. We color test specifically to make sure that we do not have a dog that looks solid but is actually a merle. 

H Locus Harlequin

Harlequin carries chocolate, fawn, and dilute

Harlequin is another co dominant gene, but the super form of harlequin is thought to be embryonic lethal. This means that if a dog possesses two harlequin genes it will not form as the embryo stage. At this time no dog has been tested that possess two copies of the harlequin gene. In order to see the harlequin gene the dog must also have the merle gene. Without the merle gene Great Dane breeders would say that the dog “carries” harlequin. This is another important reason we color test. Typically we like to make sure we have the possibility of Harlequin in every litter. To do that at least one parent must has the merle gene and at least one parent must have harlequin. So for example our female Skal is a solid black female with no merle gene. I color tested her and know she carries harlequin. This means that I can use a merle stud and still get harlequin puppies. 

Now that we know how genetics work its easy to see that other than merle and harlequin we can guarantee any color in a litter. For example if I have a waitlist with everyone wanting chocolate or lilac puppies. I can use a chocolate male that carries dilute and a lilac female. Statistically I would get 50% chocolate and 50% lilac. 

Since I can only have one copy of merle and one copy of harlequin these two genes are never a guarantee. They are also the most desirable colors. Meaning supply is low and demand is high. Typically due to the difficulty of producing these colors breeders do charge more for them. My personal opinion on the matter is that any other color I can produce guaranteed every time and so I don't charge more for those colors. I will only ever charge more for colors that are genetically difficult to produce.