We are here writing about this case because in the last years sometimes it happens, but it sounds really strange, as every German Shepherd lover knows only total black pups can be born from total black couples of parents, as is written in well known tables explaining us what colours may come out from any couple of coloured parents. So what is genetically happening?
Well, we may think it’s because of a DNA mutation, it’s not impossible, mutations occurs costantly in newborns, but even if it’s not impossible, it’s very very difficult, and we probably have to find the reason elsewhere. What most probably happened it’s… an input from another breed, or maybe even from a not purebred dog. In my opinion the most probably breed it’s Groenendael Belgian Shepherd Dog, and i think so as German Shepherds and Belgian Shepherds are similar breeds with probably common ancestry, and it’s not uncommon a cross breed between those dogs. But it’s only my idea, it could have been any similar dog with a dominant black coat gene.
Before we speak about what genetically happened to cause this, i will remind you there is a test to prove pups are really out of declared parents. If you have doubts, with a simple DNA test you may solve it by taking biological samples of mother, father and son to a genetic lab to compare it.
When a dog it’s proved not to be son of declared stud, it may have been an accident, and breeder may also noticed nothing. Sometimes bitch’s eggs are fertilized from two or more studs, as they mature in different moments. If the breeder it’s sure of the mating and suppose the pregnancy, he relaxes and let immediately the bitch together with other dogs, and if another stud mate her, and there are further eggs ready to be fertilized, pups’ father may be more than one. So it may even accidentally happen a pup it’s not son of the declared sire.
Some breeders even does it voluntarily, so he may have pups from two or more studs in the same litter, he only needs to test DNA after birth.
All those words to explain, it’s not impossible, without DNA test, to prove the father it’s not the supposed father, and a not wanted gene entered in this way.
Before we come back to talk about this strange case, i will say i am not accusing anyone, i am only explaining what may have happened and how it genetically functions. In my opinion, if it had happened so long time ago, we have to consider these dogs purebred German Shepherds, as their different genes have been diluted a lot in the years, we only have this new gene coming from outside to change some rules in the colour tables. In my opinion the only thing to really care is health and consistency with the standard.
By the way, in which way this happened, what come out are always standard German Shepherd colours and this is the only important thing. I am only explaining how it’s possible as every time it happens a lot of people are talking about the case, and so now they can remove their doubts.
Let’s at last speak about the genetic series involved in this phenomenon, which are two series between all the series concerning coat colour genetics.
I have to remember black pigment it’s called eumelanin and red pigment is called pheomelanin, the different distribution and tones of red and/or black and/or withe patches by totally absence of pigment, cause all the coat colour differences from a dogs to any other.
This is the most important series, the one telling us which colour will be our German Shepherd, Agouti series contains alleles determining black and red hairs distribution in dog’s body zones. We have 4 alleles in this series, but in German Shepherd we only find 3.
-Ay Dominant Fawn
This it’s the dominant fawn allele, we need at least one allele in the Agouti series, to get dogs looking like fawn Great Dane, fawn Pug or Tervueren Belgian Ahephers and so on. This allele it’s not present in German Shepherd, it is very easy to eliminate a not wanted allele from a series when it’s the dominant one, we only need to not reproduce fawn dogs and we will loose the Ay allele in the breed forever.
Aw-Sable after Ay, Aw is the second allele in order of dominance, w stands from wild. It’s the gray, or sable one, the most common colour for working German Shepherd Dogs. It’s the wolf colour, with some modifiers genes, but it’s the same colour, and this allele is present in a lot of wild animals because of it’s the most mimetic colour in a forest.
At-Tan Point, t stands for tan points, it’s the classic black and tan saddled German Shepherd Dog. Even if it seems we have different types of black and tan, from “Dobermann-like” black and tan to an almost all fawn black and tan dog, in the Agouti series it’s always an (At-At ) or (At-a) (a it’s the recessive black, we will soon look to). Once before sequencing alleles of this series, it was suppose there where a 5th allele, As (s for saddled) causing saddled coloured dogs, but it’s not so, it’s always At with some modifiers genes effect. Pups born very dark and then as they grows up, black retire and fawn expands until adult configuration.
a-recessive solid black
We need two a allele to have recessive solid black German Shepherd. … usually.
Let’s turn back a moment to speak about black and fawn extension as it may concerns the phenomenon.
As told before, it was supposed there was two different alleles once, one for saddled dog (As) and one for doberman-like black and tan dog (At). After sequencing all A series alleles, they found only At with probably some not yet sequenced modifiers genes influencing the black/fawn extension. As we can see on the animation, dogs may have different amount of black and fawn, and as some German Shepherd has a very little saddle and they are almost all fawn, some are so dark with black so extended saddle that they can look like total black, but they are not! This is also caused by the black mask, usually black mask covers only the muzzle, but in some cases it’s so extended that it covers also part or all dog’s legs as we usually see often in some Malinois Beligian Shepherd Dogs. If you open the next picture you see it’s not a solid black dog, it only seems to be total black but near paws there is a little fawn. This is not a solid black dog, this is a black and tan dog with only a few of tan. And probably a huge black mask covering a lot of body of the dog. But it’s an “At” dog, not a really total black dog, and if we mate it with a “a a” recessive black dog, as At it’s dominant over a, some when not all black and tan pups will born.
As the saddle extension it’s quantitative, if we cross the dogs in the last two picture we get a “standard saddled show line German Shepherd”.
When instead of a black and tan (At) we have the same characteristic of large extension of not fawn hairs and mask in a sable (Aw), we may not think it’s a total black, as in Aw case sable hairs are “banded” and it’s obvious the dog it’s not total black but sable. Modifiers genes which decide how black and tan are spread along dog’s body, probably decide also in sable dog where hairs are fawn and where are banded.
In the next picture a very dark sable German Shepherd, it’s more difficult to think it as a solid black dog.
Possible Agouti alleles couples are (Aw-Aw), (Aw-At), (Aw-a), (At-At), (At-a), (a-a)
- (Aw-Aw) (Aw-Aw) -100% (Aw-Aw) Sable
- (Aw-Aw)(Aw-At) – 50% (Aw-Aw) Homozygous Sable – 50% (Aw-At) Sable carrying Black and Tan
- (Aw-Aw)(Aw-a) – 50% (Aw-Aw) Homozygous Sable – 50% (Aw-a) Sable carrying carrying recessive solid black
- (Aw-Aw)(At-At) – 100% (Aw-At) Sable carrying Black and Tan
- (Aw-Aw)(At-a) – 50% (Aw-At) Sable carrying Black and Tan – 50% (Aw-a) Sable carrying recessive solid black
- (Aw-Aw) (a-a) – 100% (Aw-a) Sable carrying recessive solid black
- (Aw-At)(Aw-At) – 25% (Aw-Aw) Homozygous Sable – 25% (At-At) Black and Tan Homozygous – 50% (Aw-At) Sable carrying Black and Tan
- (Aw-At)(Aw-a) – 25% (Aw-Aw) Homozygous Sable 25% (Aw-At)Sable carrying Black and Tan – 25% (Aw-a) Sable carrying recessive solid black 25% At a Black and Tan carrying recessive solid black
- (Aw-At)(At-At) – 50% (Aw-At) Sable carrying Black and Tan – 50% (At-At) Homozygous Black and Tan
- (Aw-At)(At-a) – 25% (Aw-At) Sable carrying Black and Tan – 25% (Aw-a) Sable carrying recessive solid black 25% (At-At) Homozygous Black and Tan 25% (At-a) Black and Tan carrying recessive solid black
- (Aw-At)(a-a) – 50% (Aw-a) Sable carrying recessive solid black – 50% (At-a) Black and Tan carrying recessive solid black
- (Aw-a)(Aw-a) – 50% (Aw-a) Sable carrying recessive solid black 25% – (Aw-Aw) Sable Homozygous – 25% (a-a) Homozygous recessive solid black
- (Aw-a)(At-At) – 50% (Aw-At) Sable carrying Black and Tan – 50% (At-a) Black and Tan carrying recessive solid black
- (Aw-a)(At-a) – 25% (Aw-At) Sable carrying Black and Tan 25% (Aw-a) Sable carrying recessive solid black 25% (At-a) Black and Tan carrying recessive solid black 25% (a-a) Homozygous recessive solid black
- (Aw-a)(a-a) – 50% (Aw-a) Sable carrying recessive solid black 50% (a-a) Homozygous recessive solid black
- (At-At)(At-At) – 100% (At-At) Homozygous Black and Tan
- (At-At)(At-a) – 50% (At-At) Homozygous Black and Tan – 50% (At-a) Black and Tan carrying recessive solid black
- (At-At)(a-a) – 100% (At-a) Black and Tan carrying recessive solid black
- (At-a)(At-a) – 50% (At-a) Black and Tan carrying recessive solid black – 25% (At-At) Homozygous Black and Tan – 25% (a-a) Homozygous recessive solid black
- (At-a)(a-a) – 50% (At-a) Black and Tan carrying recessive solid black 50% (a-a) – Homozygous recessive solid black
Now looking to this table with possible colour combinations and offsprings, it’s obvious a total black caused by “a” gene on the Agouti series can only pass “a” (recessive black) allele to the offsprings, as it has only this alleles on this DNA locus. Every other Agouti allele combined with “a” allele it’s dominant over it and we will have a dog coloured according with the “not a” allele. Recessive dominant dogs only has two “a” alleles in the A locus. So, how it’s possible, not total black out can come out from two solid black parents?
If one or both parents are not a recessive solid black (a-a) but carries the dominant black gene, they will look total black the same, but the colour is determined by other genes in another locus, the K locus and not by the A series. So what they will pass to their offspring?
The recessive solid black “a” allele it’s not so easy to find in other breed rather tan German Shepherds, sometimes it occurs for example in Shetland Sheepdog or Belgian Shepherd dog, but usually we find it only in German Shepherd Dog. In almost any other breed total black is caused from the K allele in the K series, another Genetic series we will soon explain.
The effect caused by this gene (uppercase K) it’s called epistasis, because genes in other series will not show their presence in dog’s phenotype as their effect is covered by K (uppercase) effect. But A series genes are still present in the DNA too, and genes are passed to offspring too, even in their effect it’s not visible in the parent.
In German Shepherd dog theoretically we may not have dominant solid black, and all our problems are explained here. The gene causing this strange litters, is the dominant black gene!
So let’s talk about K locus, which has 3 alleles.
-K (uppercase), the most dominant allele, we only need one copy of this gene to have a solid black dog. For example: black Labrador are K dogs, Groenendael, black and white Border Collies and so on are K dogs
-Kbr (br stands for brindle), it’s recessive over K (uppercase) but dominant over k (lowercase).
Kbr-Kbr or Kbr-k dogs will be brindle, i mean, we will see agouti’s genes effects over the dog, but fawn patches will look like covered by a black grid. Kbr it’s like a black grid covering the dog and obviously we see the effect only on fawn zones, not black zones. When the breed was at the early stage, there was also brindle German Shepherds, but as they had always Agouti series visible, and as brindle is dominant over not brindle, the colour were escluded from breeding immediately. It’s very easy to remove a gene from a breed selection, a recessive gene may remain hidden generations over generations and it may come out any time if two dogs carriyng the gene are mated.
-k (lowercase) it would have been the only homozygous allele in the K series we may find in German Shepherd Dog, and it lets Agouti series fully express on the dog.
Well, a total black German Shepherd must be “aa kk”. If we mate together two aakk we only get aakk offspring. It’s mathematical. And it’s what we thought until not a lot of time ago.
It seems one or more total black German Shepherd Dogs imported in Western Europe from Eastern Europe are dominant solid black K. So mating those dogs with other German Shepherds has spread the K gene around the breed. Now total black german shepherds may not only be aa kk, but they may also be Kk or KK, and it doesn’t matter which alleles we have in the Agouti series, the dog will at least one uppercase K copy in the K locus always look total black as we told before.
Well, if we mate a “Kk” dog with “kk” dog, pups in the litter will get someone K, someone k from the Kk parent (with a chance of 50%). As the other parent it’s a real recessive black dog and has only “k” in K series, if the pups gets two lowercase k from both parents, we will be able to see Agouti alleles effect over the newborn dog phenotype. And this is why not solid black dogs comes out from solid black dogs.
A DOMINANT total black dog may have also recessive black (a) allele in Agouti series, it may carry one or two couple of the a gene, but it may also have Aw or At or a mixed couple of two from 3 possible alleles, if it has two a alleles, we will not see difference in dominant or recessive solid black dogs, but if he has one or both not recessive black alleles in the Agouti series (Ay or Aw) and passes the not recessive black gene to the offspring which got also two k lowercase allele from K series by parents, we will have a black and tan or sable dog according with the “not a” Agouti allele passed from the dominant black dog. This is the reason why not total black dog sometimes born from total black parents.
If both parents has a K dominant allele copy things may become more difficult to understand, so we can look to next punnet squares to predict what we can obtain by all those couples.
Remember, now K series and A series are fully testable on dog’s DNA, so if you have a double of which total black type carries your total black German Shepherd, you only need to test him for A and K allele simply taking a biological sample on a genetic institute. If we do not fink K (uppercase) allele, the last, classic table with parents-offspring colour combination it’s still good today!
Breeding results in case of K (uppercase) gene in one or both parents.
Well, now if i was clear explaining those two genetic series, you will be able to understand by yourself how colour genetics transmission functions in Belgian Shepherd Dogs.
Groenendael Belgian Shepherd is a total black and may have one or both Uppercase K in the K locus, Groenendael and Tervueren may be bred together, Tervueren has Ay allele in Agouti series, as any other Belgian Shepherd, because all Belgian Shepherds has homozygous Ay in Agouti series. When we have at least one copy of uppercase K in locus, the dog is total black. Tervueren (and Malinois and Lakenois too) has two lowercase k in the K, series so Agouti effect it’s visible upon the dog. If a Groenendael has two copies of Uppercase K in the K series, all his offspring will be total black as he can pass only K to offspring, by the way if uppercase K it’s only one, the chance to pass a lowercase k to offspring is 50%. Breeding two lowercase k carrier Groenendael or a lowercase k Groenendael carrier with a Tervueren (homozygous lowercase k) will result in a litter with both Ay Agouti and dominant black pups.