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by Hundmutter on 07 September 2021 - 14:09
The old thred (and one or two others) discusses Dominant Black - but does not prove its existence. The Laboklin lab is still in existence; maybe I'll try & see if they ever came up with the appropriate proof on the K series. 2012 is quite some time ago, and some more work has I think been done on GSD colour genes, but I don't think I have seen anything in all those 9 years to indicate the allele has ever been found.
by Rik on 07 September 2021 - 18:09
I am really surprised that there is not more information on this. As there is no mention of dominant black in 100+ years of GSD history, I tend to agree that maybe something extra got added, probably many generations back.
anyway, just from the pics, some are very handsome dogs, and if one ever comes to the U.S. and starts winning in AKC/GSDCA shows, then there will be people (the ones not winning) who will get to the bottom of this in short order.
anyway, just from the pics, some are very handsome dogs, and if one ever comes to the U.S. and starts winning in AKC/GSDCA shows, then there will be people (the ones not winning) who will get to the bottom of this in short order.
by lottas on 07 September 2021 - 18:09
Dear German Shepherd Fans!
I since 2008 am studying a theme of the dominant black German Shepherds. Around that time they first appeared at shows in Russia. They are really dominant black dogs, the inheritance of black color in them is a dominant type.
Over 13 years I have written several articles on the subject. Unfortunately, they are only in Russian, but if someone can translate them into different languages, I would be glad:
https://lottasstyle.wixsite.com/info/ochernomokrase
https://lottasstyle.wixsite.com/info/black
Besides, I have some videos on my Youtube-channel about the black dominant coloration in a German Shepherd, but they are in Russian too:
https://www.youtube.com/watch?v=ptqftlVbnoU
https://www.youtube.com/watch?v=PYK0a937PSg
https://www.youtube.com/watch?v=ckVubpADfb8
https://www.youtube.com/watch?v=bacs0Cl4F2s
In Russia, the first dominant black dogs appeared at shows in 2008, but in fact a small number of them existed before. Two lines of these dogs stretched from the 50s and they go back to a black male dog brought from the GDR - Nitus von Haus Konigsfreunde.
I have analyzed the origin of these dogs and found several blood lines of dominant blacks that existed in the breed from its very beginnings, but apparently, they have not survived anywhere, except Russia.
This is a scheme of German lines of dominant black dogs in the past. This is confirmed by many years of analysis of their origin, inheritance of color in transmission to descendants.
https://ckvno.pp.ua/wp-content/uploads/2021/05/k-linii.jpg
Unfortunately because of the language barrier it is difficult for me to communicate (I write through a translator), but I hope someone can translate and study these materials.
I want to say that although the dominant black dogs are purebred, but their breeding is associated with serious problems in the inheritance of color. They rarely give a solid black color, mostly they have large areas of lightening in atypical places.
I since 2008 am studying a theme of the dominant black German Shepherds. Around that time they first appeared at shows in Russia. They are really dominant black dogs, the inheritance of black color in them is a dominant type.
Over 13 years I have written several articles on the subject. Unfortunately, they are only in Russian, but if someone can translate them into different languages, I would be glad:
https://lottasstyle.wixsite.com/info/ochernomokrase
https://lottasstyle.wixsite.com/info/black
Besides, I have some videos on my Youtube-channel about the black dominant coloration in a German Shepherd, but they are in Russian too:
https://www.youtube.com/watch?v=ptqftlVbnoU
https://www.youtube.com/watch?v=PYK0a937PSg
https://www.youtube.com/watch?v=ckVubpADfb8
https://www.youtube.com/watch?v=bacs0Cl4F2s
In Russia, the first dominant black dogs appeared at shows in 2008, but in fact a small number of them existed before. Two lines of these dogs stretched from the 50s and they go back to a black male dog brought from the GDR - Nitus von Haus Konigsfreunde.
I have analyzed the origin of these dogs and found several blood lines of dominant blacks that existed in the breed from its very beginnings, but apparently, they have not survived anywhere, except Russia.
This is a scheme of German lines of dominant black dogs in the past. This is confirmed by many years of analysis of their origin, inheritance of color in transmission to descendants.
https://ckvno.pp.ua/wp-content/uploads/2021/05/k-linii.jpg
Unfortunately because of the language barrier it is difficult for me to communicate (I write through a translator), but I hope someone can translate and study these materials.
I want to say that although the dominant black dogs are purebred, but their breeding is associated with serious problems in the inheritance of color. They rarely give a solid black color, mostly they have large areas of lightening in atypical places.
by Rik on 07 September 2021 - 18:09
lottas, thank you for your input. very interesting and the translation was clear.
Rik
Rik
by kitkat3478 on 13 September 2021 - 17:09
ut the black color of the German Shepherd
I was prompted to write this article by the situation that has developed in the breed today and has turned all the breeders' ideas about the laws of inheritance of the colors of the German shepherd. In the breed, which has more than a century of history, which is the most numerous and widespread across the globe, the genetics of colors of which have been studied "far and wide" by specialists of many generations, for some time now strange things have begun to happen. But before talking about this, it is worth touching on history and the classic state of affairs, which is still preserved throughout the civilized world.
The German Shepherd has always had four standard colors: zoned, black-backed, black and tan and black. This is one of the few breeds whose colors are formed by only one locus A (agouti), which includes three color-forming genes - aw, at, a. The genes of other loci, one way or another responsible for the color, are either in an inoperative state, or can only affect the intensity of the pigment, the presence of gray hair on the saddle, the appearance of white marks in characteristic places, but in no way form a new color unusual for the breed. The only exception is the d gene, which is responsible for weakening the black pigment and causing the blue color, which is rarely found in the German shepherd. But since this color was never considered standard, blue puppies born occasionally were always subject to culling, and the number of carriers of this gene is negligible,
Thus, only three genes from the A locus remain, which form the color of the German shepherd. But before characterizing each of them, it is worth saying that the agouti locus is the most significant in the existence of the canine species, since it provides an ideal balance of pigments - eumelanins and pheomelanins and is responsible for the coloration necessary for better adaptation to the environment. These genes, one might say, form the primordial colors of dogs, the rest are the result of mutations that have arisen at one time or another.
So, the aw gene, or the gene that forms the zonal color, is the most dominant at this locus. It can exist in the German Shepherd Dog only in the dominant variant. In other words, if a dog has this gene, outwardly it will always be sounder. In a recessive (latent) state, this gene does not exist in the breed. The pattern, the intensity of black and red pigment is influenced by genes from other loci or modifier genes.
The second in this list is the at gene, or the gene that forms the black and black and tan colors. It is recessive in relation to the zone and dominant in relation to black, that is, it can exist in a recessive (latent) state in zone dogs, and the zone and black-backed dogs can be carriers of the recessive gene for black color. Previously, it was believed that at is responsible only for the formation of black and tan color, and black and brown is formed by another gene - asa. But recent scientific studies have shown that the asa gene is not present in this locus and these two colors are formed only by the at gene, and the size of the tan is additionally controlled by the modifier gene, which probably also has two alleles, because in practice the black and back color dominates over the black color. tan. But since this modifier gene does not yet have a name,
And the last - gene a, or the gene of black color - is recessive in relation to all genes of this locus. In other words, a black dog will always have a paired allele aa and can never be a gene noostelle of sounder, black-backed or black-and-tan colors.
These genes form ten possible alleles:
awaw - zoned homozygous
awat (asa) - zoned heterozygous, carrier
black-backed awat - zoned heterozygous, carrier black and tan
awa - zoned heterozygous, carrier black
at (asa) at (asa) - black- backed homozygous -
at (asa) black & tan heterozygous, carrier of black and tan color
at (asa) a -
black & tan heterozygous, carrier of black color atat - black & tan homozygous
ata - black & tan heterozygous, carrier of black color
aa - black homozygous
There are 55 possible combinations between these alleles, the detailed description of which I gave in the corresponding section of the last edition of my book "Breeding and raising a German shepherd". I think there is no special need to transfer this entire table here, especially since further we will talk directly about the black color, so we will limit ourselves only to information about it. But first, it should be noted that none of the color of the German Shepherd has advantages over others, none of them is undesirable or not recommended for widespread use. Moreover, in order to preserve good pigmentation and genome stability, experts have always called for the careful preservation of all colors available in the breed and mating of dogs of different colors among themselves. The only exception is, perhaps, the only recommendation to avoid mating two black dogs, which is fraught with the appearance of a lighter undercoat in the offspring. I must say that the organic ratio of all colors in the breed was traced right up to the 80s, and most of the sounder and black-backed dogs were carriers of the recessive black gene and gave black puppies.
However, fashion is a capricious lady, she did not bypass the German shepherd. At the turn of the 80s, when show-exhibitions firmly entered our life, the interest of breed lovers gradually began to lean towards the most spectacular, black-backed color. Bright red dogs with a well-defined mask were especially appreciated. Owners of a "deep" saddlecloth extending to the shoulders, hips and limbs were not welcome. But it is they, according to the observations of many generations of breeders, who are carriers of the recessive gene a, and producers of black color. It did not take long for the sounder, black and tan and black dogs to practically disappear from the show rings, and gradually from breeding. And when it was possible to put an end to the existence of these colors in modern show breeding, the insidious fashion suddenly changed its priorities.
The beginning of the 2000s was a period of mass hunting for colors that are rare in the breed. And if single specimens of sounder dogs are still preserved in separate kennels in Germany, then it was simply impossible to find black shepherd dogs of the modern type. Now it is worth explaining in more detail why.
The black color in the German shepherd is formed by the recessive gene a and it can appear in the offspring only under certain conditions:
- if both parents are black - aa + aa = aa + aa + aa + aa (all descendants will be black)
- if one of the parents is black, and the second, regardless of color, has a recessive gene in the genotype a - awa + aa = awa + aa or ata + aa = ata + aa (about half of the offspring will have black color)
- if both parents are sounder or black-backed, but both have a recessive gene in their genotype a - awa + awa = awaw + awa + aa or ata + ata = atat + ata + aa or awa + ata = awat + awa + ata + aa (some of the puppies will be black)
If at least one of the parents does not have a recessive gene a, black puppies from this pair will never be obtained, even if the second breeder is solid black! This is a classic that has been studied and described by genetic scientists for hundreds of years, tested by breeders and has never raised doubts in anyone.
Therefore, when the fashion for blacks came, it turned out to be impossible to revive this color in the show population, emasculated by the recessive gene a. There was only one way out - to practice mating females with working breeding males, where there was still a sufficient number of dogs of zonar and black color, but where for many years there was practically no selection for exterior qualities. But for breeders focused primarily on exhibitions, this practice seemed very dubious. In addition, to obtain black puppies, more than one such mating was needed, but to obtain high quality black puppies - not two, and not three. And this is already a long and difficult path, which does not guarantee success at all. Therefore, in most countries, attempts to revive the black color in the breed were abandoned by the breeders at the initial stage, and some black dogs, if they were obtained, then due to their non-competitiveness in the show rings, they did not play any role in the further development of the breed. It would seem that breeders all over the world have come to terms with the inevitable loss of this color in the breed ...
And suddenly at the Russian exhibitions in 2008, like "snow on the heads" of the pedigree, a black handsome Shaitan appears! A dog of a modern type, excellent exterior, with excellent character and decent working qualities, but most importantly - the result of Russian breeding in several generations! The judges shrug their shoulders in bewilderment, shrug their shoulders, but invariably put this dog in the head of the rings. Breeders begin to intensively study his pedigree and discover that Shaitan comes from the same black handsome man - Pharaoh. Both grandfather and great-grandfather, and Shaitan's littermate - Sheikh, turned out to be wonderful black dogs! It seems that none of the Russians then remained indifferent and proud of domestic breeding: after all, not in Germany or in any other country in the world, but in Russia, they managed to save the black German shepherd! No one could have thought of some kind of "wrong" and uncharacteristic inheritance of this color for the breed, everyone was only surprised how this line of black and rather beautiful shepherd dogs remained unnoticed and unknown to a wide circle of breeders. The people rushed to mate with Shaitan and his closest relatives, rightly believing that, of course, they cannot get black puppies from homozygous black-backed bitches, but there is a chance to revive the black color through their descendants, without losing quality ...
Imagine the surprise of the breeders when puppies of black color began to be born from Shaitan, Sheikh and Pharaoh in each litter! Moreover, their number was at least half of all puppies born! The fact that the heredity of these producers did not fit into the classical scheme was openly discussed only after a year of their active breeding use, when a sufficient number of puppies had already been obtained. What assumptions breeders did not build! And that this is a new form of agouti color caused by a mutation, and that the color of Shaitan and his closest relatives is not black at all, but so dark zoned that it visually appears black, and that this is not a recessive, but a real dominant gene of black color, characteristic of such breeds as the Labrador, Great Dane, Cane Corso. Anyway, the inheritance of black color in this line occurred according to the classical dominant type and this was the most logical version. However, this meant that an alien gene appeared in the breed, belonging to the K locus, which had never been in it before, and, accordingly, all dogs of this line had to be considered non-purebred. On the forums, the controversy about the nature of this black color did not subside, and in the meantime, the most enterprising breeders continued to "cut coupons". In the wake of the ever-increasing fashion for black color, puppies from these manufacturers used, and still are still in high demand among buyers. Soon, another line of black German shepherds with a dominant type of heredity was discovered in Belarus. A detailed study of the pedigrees of the St. Petersburg Pharaoh and the Belarusian Eustace, it turned out,
The end of the controversy was a genetic examination, made unofficially by the most curious owners of black shepherd dogs, the results of which were not made public. But "you can't hide an awl in a sack", and soon everyone knew that the most logical version was confirmed - the descendants of Pharaoh and Eustace, indeed, have a black color formed by the K gene and inherited by the dominant type.
For a more complete picture of what is happening, it is necessary to characterize the K locus and the work of its genes.
Locus K is responsible for the distribution of black / brown pigment in the coat and includes three genes:
- the dominant gene K - the gene of solid color, which paints any color formed by locus A with eumelanin paint, is normally absent in the German shepherd
- the recessive gene kbr with respect to it - works on the principle of partial filling with eumelanin paint of any color of locus A, forming a brindle color ( black or brown stripes on a red background), is absent in the German Shepherd
- recessive with respect to all genes of this locus, gene k (ky), which does not prevent the expression of genes of other loci, in particular agouti colors, is the only gene of this locus available in the German shepherd dogs.
The order of dominance of genes of this locus: K> kbr> k
Based on this, it is obvious that in a population where only the recessive gene k exists, the appearance of its dominant form K is impossible.
To visualize the situation that occurred in the breed, let us first consider the working formulas of the classic German Shepherd colors, for simplicity, omitting the genes of other loci responsible for the intensity of the pigment (I), earlier graying (G) and white markings (S), and adding only the genes locus B, black pigment.
awaw BB kk - zoned homozygous
awat (asa) BB kk - zoned heterozygous, carrier
black-backed awat BB kk - zoned heterozygous, carrier black and tan
awa BB kk - zoned heterozygous, carrier black
at (asa) at (asa) BB kk -
black and back homozygous at (asa) at BB kk - black and tan heterozygous, carrier of black and tan
at (asa) a
BB kk - black and tan heterozygous, carrier of black atat BB kk - black and tan homozygous
ata BB kk - black and tan heterozygous , carrier of black color
aa BB kk - black homozygous
Having even a superficial understanding of the composition of color formulas, it is easy to see - no matter how the alleles of the color-forming loci are combined with each other, the appearance of black shepherd dogs in a breed is possible only from a combination of two recessive genes of a black color (aa). But there is another way - cross-breeding. A single mating with a black dog of another breed, the genotype of which has the dominant form of the K locus, is enough for this trait to be fixed in the population, and subsequent pairs of matings, in order to remove features uncharacteristic for the breed from the offspring by the method of backcrossing, leaving only the black color inherited by dominant type.
Where could this gene have come from into the breed? The most likely version of the emergence of a black dominant color from the Great Danes, which in the 30s of the last century crossed with German Shepherds to develop a new domestic breed called the Moscow Great Dane, seems to me the most probable. As you know, these experiments turned out to be unsuccessful, and it is very possible that the resulting mestizos again got into the breeding of the German (East European) shepherd dog, introducing into it an alien dominant gene K. And since black shepherds were not in favor for a long time and mated very limited, no one paid attention to their unusual heredity. There is another version - about the purposeful infusion of the blood of the black Labrador and Groenendael, which has already occurred today. Which of them is more consistent is difficult to say, it is possible that both took place.
The emergence of dominant blacks led not only to the birth of a large number of black puppies in the first generation, but, much more seriously, completely changed the picture of the classic inheritance of all colors in the breed. These dogs and their descendants no longer fit into the scheme of 55 possible combinations. In order to understand why this happens, you just need to understand the nature of the dominant black color formed by the K.
So, the dominant gene K is a gene of solid eumelanin color. In fairness, it should be noted that according to the latest scientific data, this gene encodes one of the proteins responsible for the dog's immunity. Consequently, its carriers must have better immune protection than carriers of the recessive gene k. But at the same time, the expression of the K gene and its interaction with the genes of the E locus (responsible for the production of black paint) or Em (the presence of a mask) determines its specific effect on the dog's color and causes a number of negative changes, which will be discussed below.
Even if the dog is a sounder, black-backed or black-and-tan carrier at the A locus, the action of the K gene makes it solid black. In other words, this gene, as soon as it is in the genotype, fills the dog's coat with a solid black color, disguising under itself any other color formed by the genes of the agouti locus:
awaw BB Kk - black (locus A - zonal)
awat (asa) BB Kk - black (locus A - zonal)
awat BB Kk - black (locus A - zonal)
awa BB Kk - black (locus A - zonal )
at (asa) at (asa) BB Kk - black (locus A - black-backed)
at (asa) at BB Kk - black (locus A - black-backed)
at (asa) a BB Kk - black (locus A -
black & brown ) atat BB Kk - black (locus A - black and tan)
ata BB Kk - black (locus A - black and tan)
aa BB Kk - black (double black)
When mating such dogs with a black-backed, black-and-tan partners with a classic recessive kk-genotype, approximately half of the black heterozygotes with the Kk genotype and half of the classic-colored dogs with the kk genotype will be born. When mating two dominant blacks (Kk), the progeny will split according to Mendel's laws - approximately 25% black homozygotes (KK), 50% black heterozygotes (Kk), and 25% classic dogs (kk). But carriers of two dominant KK (black homozygotes) in any combination will give only black puppies!
And now about the worst. As can be seen from the above examples, dominant black is not only able to hide the color of a dog formed by locus A and "mix up all the cards" in the classical pattern of inheritance of colors, it is phenotypically the most dominant color of all existing and, if appropriate measures are not taken, tends to wide progressive distribution in the breed.
Inheritance table of colors of the German shepherd, taking into account the dominant black gene for locus K
In addition, dominant black shepherd dogs rarely have a pure solid color. Most often, with age, their undercoat acquires a brownish-grayish tint, and noticeably lightened areas appear in the tan areas, in the groin, and often on the neck, thighs, in the shoulder area and even along the body. This is not surprising - the expression of the K gene is not always enough to hide the colors of the agouti locus under its eumelanin "veil". And it will never be possible to get rid of these pigmentation problems in dominant blacks ... As a result, their owners are already beginning to master the tricks of the modern pet industry, more and more dyed black dogs appear at exhibitions ... Is this what we would like for our breed?
Впрочем, вопрос риторический, больше волнующий тех заводчиков, которые остались верны породным традициям и не пошли на поводу у моды. Они же, в первую очередь обеспокоены вопросами, связанными с появлением гена доминантного черного окраса в породе. Кем и когда была сделана та роковая вязка? Была ли она случайной или целенаправленной? Собаки каких пород послужили исходным материалом для этих экспериментов? Сколько поколений прошло с тех пор? И что делать дальше с этим, уже довольно большим по численности поголовьем? Все эти вопросы пока еще остаются открытыми. Но рано или поздно они потребуют ответа.
In the meantime ... while we are forced to observe how enterprising admirers of the dominant black color continue to "stamp" puppies in demand in our market and listen "far-fetched" arguments about its appearance in the breed - they say, mutation ... or preservation gene K in individual blood lines since the founding of the breed, which for more than a hundred years has gone unnoticed! Even the nickname of one of the German breeders of the 50s is called, which allegedly had a dominant black color and gave black puppies in each litter. But the fact that almost all the livestock of those years were heterozygous for the black recessive color is somehow not given importance ... And all these arguments, against the background of a surprised question - How did the dominant blacks prevent you? Yes, in fact, nothing, except for one thing - they are not purebred.
In this regard, it is worth remembering that the German Shepherd has always belonged to the purebred breeds. That is, for its creation, improvement and reproduction, dogs of other breeds have never been used and the pedigrees of modern German shepherds can be traced back to its ancestors - this is what, according to zootechnical standards, distinguishes a purebred breed from a purebred one. A true breeder cannot ignore this fact. In addition, the homeland of this breed is Germany, which has the prerogative in addressing such important issues as the expediency of adding other bloodlines, changing the standard and compliance with other important characteristics, which undoubtedly include the genome of the population. For now, the Germans shrug their shoulders in bewilderment when they hear about the miracles of genetics taking place in Russia, Ukraine, Belarus with their national breed. While not yet understanding the scale of this phenomenon, they recommend doing a DNA analysis for the reliability of the origin, having heard about the next black phenomenon. But this is for now. Until the black dominants got into the breeding of SVs and did not affect their national interests ... It is difficult to say what will happen next. Will the luminaries of the breed want to adopt a different genetics and transfer the German Shepherd from the category of purebred breeds to the category of conditionally purebred? Or would they prefer to put the dominant blacks out of the breed with one stroke of the pen? And won't there be another breed group after that, not recognized by the FCI? Time will show... It's hard to say what will happen next. Will the luminaries of the breed want to adopt a different genetics and transfer the German Shepherd from the category of purebred breeds to the category of conditionally purebred? Or would they prefer to put the dominant blacks out of the breed with one stroke of the pen? And won't there be another breed group after that, not recognized by the FCI? Time will show... It's hard to say what will happen next. Will the luminaries of the breed want to adopt a different genetics and transfer the German Shepherd from the category of purebred breeds to the category of conditionally purebred? Or would they prefer to put the dominant blacks out of the breed with one stroke of the pen? And won't there be another breed group after that, not recognized by the FCI? Time will show...
In conclusion, I want to quote a paragraph from the wonderful and extremely useful for all breeders book by Larisa Pasechnik "Dog Colors", which, as it seems to me, can be put as an epilogue to all these arguments:
In the pedigrees of dogs, completely strange names of colors suddenly begin to appear, under the motto of poetic and national characteristics in terminology. It is impossible to understand what color is meant without seeing the dog, and by a strange coincidence, the dogs are more and more unknown, and neither the photos nor the dogs themselves can already be seen. Nevertheless, in some places there are obvious blunders and, if desired, it is quite possible to get to the bottom of the truth. It's just that hardly anyone wants to dig into it.
And yet, sooner or later it will happen. Genetics is still a science, and a wonderful science. Now with might and main is the study of mitochondrial DNA of many biological species, including dogs. Mitochondria - large organelles located in the cytoplasm of the cell, provide cellular respiration, and, in addition, are carriers of genetic information. It turns out that not all hereditary information is concentrated in chromosomes, but only slightly more than 90%, the rest of the information is contained in mitochondrial genes, as well as in small cellular inclusions, often of an infectious nature. The collection of cytoplasmic genes is referred to as "plasmon". Plasmogens are transmitted to descendants mainly through the maternal line, because sperm have a negligible amount of plasmagens. This feature,
In the future, it is possible to compile a complete family tree of the species, with accurate answers to such exciting questions as the origin of each of the breeds, indicating the time of birth of the breed, ancestors, and even when crossing with other breeds and with which ones took place. Then the secret will become apparent, and the world will recognize its heroes. "
Lyudmila Arkhangelskaya, 2013
Using materials from the book by Larisa Pasechnik
"Colors of dogs. Genetic, biochemical and molecular biological aspects"
I was prompted to write this article by the situation that has developed in the breed today and has turned all the breeders' ideas about the laws of inheritance of the colors of the German shepherd. In the breed, which has more than a century of history, which is the most numerous and widespread across the globe, the genetics of colors of which have been studied "far and wide" by specialists of many generations, for some time now strange things have begun to happen. But before talking about this, it is worth touching on history and the classic state of affairs, which is still preserved throughout the civilized world.
The German Shepherd has always had four standard colors: zoned, black-backed, black and tan and black. This is one of the few breeds whose colors are formed by only one locus A (agouti), which includes three color-forming genes - aw, at, a. The genes of other loci, one way or another responsible for the color, are either in an inoperative state, or can only affect the intensity of the pigment, the presence of gray hair on the saddle, the appearance of white marks in characteristic places, but in no way form a new color unusual for the breed. The only exception is the d gene, which is responsible for weakening the black pigment and causing the blue color, which is rarely found in the German shepherd. But since this color was never considered standard, blue puppies born occasionally were always subject to culling, and the number of carriers of this gene is negligible,
Thus, only three genes from the A locus remain, which form the color of the German shepherd. But before characterizing each of them, it is worth saying that the agouti locus is the most significant in the existence of the canine species, since it provides an ideal balance of pigments - eumelanins and pheomelanins and is responsible for the coloration necessary for better adaptation to the environment. These genes, one might say, form the primordial colors of dogs, the rest are the result of mutations that have arisen at one time or another.
So, the aw gene, or the gene that forms the zonal color, is the most dominant at this locus. It can exist in the German Shepherd Dog only in the dominant variant. In other words, if a dog has this gene, outwardly it will always be sounder. In a recessive (latent) state, this gene does not exist in the breed. The pattern, the intensity of black and red pigment is influenced by genes from other loci or modifier genes.
The second in this list is the at gene, or the gene that forms the black and black and tan colors. It is recessive in relation to the zone and dominant in relation to black, that is, it can exist in a recessive (latent) state in zone dogs, and the zone and black-backed dogs can be carriers of the recessive gene for black color. Previously, it was believed that at is responsible only for the formation of black and tan color, and black and brown is formed by another gene - asa. But recent scientific studies have shown that the asa gene is not present in this locus and these two colors are formed only by the at gene, and the size of the tan is additionally controlled by the modifier gene, which probably also has two alleles, because in practice the black and back color dominates over the black color. tan. But since this modifier gene does not yet have a name,
And the last - gene a, or the gene of black color - is recessive in relation to all genes of this locus. In other words, a black dog will always have a paired allele aa and can never be a gene noostelle of sounder, black-backed or black-and-tan colors.
These genes form ten possible alleles:
awaw - zoned homozygous
awat (asa) - zoned heterozygous, carrier
black-backed awat - zoned heterozygous, carrier black and tan
awa - zoned heterozygous, carrier black
at (asa) at (asa) - black- backed homozygous -
at (asa) black & tan heterozygous, carrier of black and tan color
at (asa) a -
black & tan heterozygous, carrier of black color atat - black & tan homozygous
ata - black & tan heterozygous, carrier of black color
aa - black homozygous
There are 55 possible combinations between these alleles, the detailed description of which I gave in the corresponding section of the last edition of my book "Breeding and raising a German shepherd". I think there is no special need to transfer this entire table here, especially since further we will talk directly about the black color, so we will limit ourselves only to information about it. But first, it should be noted that none of the color of the German Shepherd has advantages over others, none of them is undesirable or not recommended for widespread use. Moreover, in order to preserve good pigmentation and genome stability, experts have always called for the careful preservation of all colors available in the breed and mating of dogs of different colors among themselves. The only exception is, perhaps, the only recommendation to avoid mating two black dogs, which is fraught with the appearance of a lighter undercoat in the offspring. I must say that the organic ratio of all colors in the breed was traced right up to the 80s, and most of the sounder and black-backed dogs were carriers of the recessive black gene and gave black puppies.
However, fashion is a capricious lady, she did not bypass the German shepherd. At the turn of the 80s, when show-exhibitions firmly entered our life, the interest of breed lovers gradually began to lean towards the most spectacular, black-backed color. Bright red dogs with a well-defined mask were especially appreciated. Owners of a "deep" saddlecloth extending to the shoulders, hips and limbs were not welcome. But it is they, according to the observations of many generations of breeders, who are carriers of the recessive gene a, and producers of black color. It did not take long for the sounder, black and tan and black dogs to practically disappear from the show rings, and gradually from breeding. And when it was possible to put an end to the existence of these colors in modern show breeding, the insidious fashion suddenly changed its priorities.
The beginning of the 2000s was a period of mass hunting for colors that are rare in the breed. And if single specimens of sounder dogs are still preserved in separate kennels in Germany, then it was simply impossible to find black shepherd dogs of the modern type. Now it is worth explaining in more detail why.
The black color in the German shepherd is formed by the recessive gene a and it can appear in the offspring only under certain conditions:
- if both parents are black - aa + aa = aa + aa + aa + aa (all descendants will be black)
- if one of the parents is black, and the second, regardless of color, has a recessive gene in the genotype a - awa + aa = awa + aa or ata + aa = ata + aa (about half of the offspring will have black color)
- if both parents are sounder or black-backed, but both have a recessive gene in their genotype a - awa + awa = awaw + awa + aa or ata + ata = atat + ata + aa or awa + ata = awat + awa + ata + aa (some of the puppies will be black)
If at least one of the parents does not have a recessive gene a, black puppies from this pair will never be obtained, even if the second breeder is solid black! This is a classic that has been studied and described by genetic scientists for hundreds of years, tested by breeders and has never raised doubts in anyone.
Therefore, when the fashion for blacks came, it turned out to be impossible to revive this color in the show population, emasculated by the recessive gene a. There was only one way out - to practice mating females with working breeding males, where there was still a sufficient number of dogs of zonar and black color, but where for many years there was practically no selection for exterior qualities. But for breeders focused primarily on exhibitions, this practice seemed very dubious. In addition, to obtain black puppies, more than one such mating was needed, but to obtain high quality black puppies - not two, and not three. And this is already a long and difficult path, which does not guarantee success at all. Therefore, in most countries, attempts to revive the black color in the breed were abandoned by the breeders at the initial stage, and some black dogs, if they were obtained, then due to their non-competitiveness in the show rings, they did not play any role in the further development of the breed. It would seem that breeders all over the world have come to terms with the inevitable loss of this color in the breed ...
And suddenly at the Russian exhibitions in 2008, like "snow on the heads" of the pedigree, a black handsome Shaitan appears! A dog of a modern type, excellent exterior, with excellent character and decent working qualities, but most importantly - the result of Russian breeding in several generations! The judges shrug their shoulders in bewilderment, shrug their shoulders, but invariably put this dog in the head of the rings. Breeders begin to intensively study his pedigree and discover that Shaitan comes from the same black handsome man - Pharaoh. Both grandfather and great-grandfather, and Shaitan's littermate - Sheikh, turned out to be wonderful black dogs! It seems that none of the Russians then remained indifferent and proud of domestic breeding: after all, not in Germany or in any other country in the world, but in Russia, they managed to save the black German shepherd! No one could have thought of some kind of "wrong" and uncharacteristic inheritance of this color for the breed, everyone was only surprised how this line of black and rather beautiful shepherd dogs remained unnoticed and unknown to a wide circle of breeders. The people rushed to mate with Shaitan and his closest relatives, rightly believing that, of course, they cannot get black puppies from homozygous black-backed bitches, but there is a chance to revive the black color through their descendants, without losing quality ...
Imagine the surprise of the breeders when puppies of black color began to be born from Shaitan, Sheikh and Pharaoh in each litter! Moreover, their number was at least half of all puppies born! The fact that the heredity of these producers did not fit into the classical scheme was openly discussed only after a year of their active breeding use, when a sufficient number of puppies had already been obtained. What assumptions breeders did not build! And that this is a new form of agouti color caused by a mutation, and that the color of Shaitan and his closest relatives is not black at all, but so dark zoned that it visually appears black, and that this is not a recessive, but a real dominant gene of black color, characteristic of such breeds as the Labrador, Great Dane, Cane Corso. Anyway, the inheritance of black color in this line occurred according to the classical dominant type and this was the most logical version. However, this meant that an alien gene appeared in the breed, belonging to the K locus, which had never been in it before, and, accordingly, all dogs of this line had to be considered non-purebred. On the forums, the controversy about the nature of this black color did not subside, and in the meantime, the most enterprising breeders continued to "cut coupons". In the wake of the ever-increasing fashion for black color, puppies from these manufacturers used, and still are still in high demand among buyers. Soon, another line of black German shepherds with a dominant type of heredity was discovered in Belarus. A detailed study of the pedigrees of the St. Petersburg Pharaoh and the Belarusian Eustace, it turned out,
The end of the controversy was a genetic examination, made unofficially by the most curious owners of black shepherd dogs, the results of which were not made public. But "you can't hide an awl in a sack", and soon everyone knew that the most logical version was confirmed - the descendants of Pharaoh and Eustace, indeed, have a black color formed by the K gene and inherited by the dominant type.
For a more complete picture of what is happening, it is necessary to characterize the K locus and the work of its genes.
Locus K is responsible for the distribution of black / brown pigment in the coat and includes three genes:
- the dominant gene K - the gene of solid color, which paints any color formed by locus A with eumelanin paint, is normally absent in the German shepherd
- the recessive gene kbr with respect to it - works on the principle of partial filling with eumelanin paint of any color of locus A, forming a brindle color ( black or brown stripes on a red background), is absent in the German Shepherd
- recessive with respect to all genes of this locus, gene k (ky), which does not prevent the expression of genes of other loci, in particular agouti colors, is the only gene of this locus available in the German shepherd dogs.
The order of dominance of genes of this locus: K> kbr> k
Based on this, it is obvious that in a population where only the recessive gene k exists, the appearance of its dominant form K is impossible.
To visualize the situation that occurred in the breed, let us first consider the working formulas of the classic German Shepherd colors, for simplicity, omitting the genes of other loci responsible for the intensity of the pigment (I), earlier graying (G) and white markings (S), and adding only the genes locus B, black pigment.
awaw BB kk - zoned homozygous
awat (asa) BB kk - zoned heterozygous, carrier
black-backed awat BB kk - zoned heterozygous, carrier black and tan
awa BB kk - zoned heterozygous, carrier black
at (asa) at (asa) BB kk -
black and back homozygous at (asa) at BB kk - black and tan heterozygous, carrier of black and tan
at (asa) a
BB kk - black and tan heterozygous, carrier of black atat BB kk - black and tan homozygous
ata BB kk - black and tan heterozygous , carrier of black color
aa BB kk - black homozygous
Having even a superficial understanding of the composition of color formulas, it is easy to see - no matter how the alleles of the color-forming loci are combined with each other, the appearance of black shepherd dogs in a breed is possible only from a combination of two recessive genes of a black color (aa). But there is another way - cross-breeding. A single mating with a black dog of another breed, the genotype of which has the dominant form of the K locus, is enough for this trait to be fixed in the population, and subsequent pairs of matings, in order to remove features uncharacteristic for the breed from the offspring by the method of backcrossing, leaving only the black color inherited by dominant type.
Where could this gene have come from into the breed? The most likely version of the emergence of a black dominant color from the Great Danes, which in the 30s of the last century crossed with German Shepherds to develop a new domestic breed called the Moscow Great Dane, seems to me the most probable. As you know, these experiments turned out to be unsuccessful, and it is very possible that the resulting mestizos again got into the breeding of the German (East European) shepherd dog, introducing into it an alien dominant gene K. And since black shepherds were not in favor for a long time and mated very limited, no one paid attention to their unusual heredity. There is another version - about the purposeful infusion of the blood of the black Labrador and Groenendael, which has already occurred today. Which of them is more consistent is difficult to say, it is possible that both took place.
The emergence of dominant blacks led not only to the birth of a large number of black puppies in the first generation, but, much more seriously, completely changed the picture of the classic inheritance of all colors in the breed. These dogs and their descendants no longer fit into the scheme of 55 possible combinations. In order to understand why this happens, you just need to understand the nature of the dominant black color formed by the K.
So, the dominant gene K is a gene of solid eumelanin color. In fairness, it should be noted that according to the latest scientific data, this gene encodes one of the proteins responsible for the dog's immunity. Consequently, its carriers must have better immune protection than carriers of the recessive gene k. But at the same time, the expression of the K gene and its interaction with the genes of the E locus (responsible for the production of black paint) or Em (the presence of a mask) determines its specific effect on the dog's color and causes a number of negative changes, which will be discussed below.
Even if the dog is a sounder, black-backed or black-and-tan carrier at the A locus, the action of the K gene makes it solid black. In other words, this gene, as soon as it is in the genotype, fills the dog's coat with a solid black color, disguising under itself any other color formed by the genes of the agouti locus:
awaw BB Kk - black (locus A - zonal)
awat (asa) BB Kk - black (locus A - zonal)
awat BB Kk - black (locus A - zonal)
awa BB Kk - black (locus A - zonal )
at (asa) at (asa) BB Kk - black (locus A - black-backed)
at (asa) at BB Kk - black (locus A - black-backed)
at (asa) a BB Kk - black (locus A -
black & brown ) atat BB Kk - black (locus A - black and tan)
ata BB Kk - black (locus A - black and tan)
aa BB Kk - black (double black)
When mating such dogs with a black-backed, black-and-tan partners with a classic recessive kk-genotype, approximately half of the black heterozygotes with the Kk genotype and half of the classic-colored dogs with the kk genotype will be born. When mating two dominant blacks (Kk), the progeny will split according to Mendel's laws - approximately 25% black homozygotes (KK), 50% black heterozygotes (Kk), and 25% classic dogs (kk). But carriers of two dominant KK (black homozygotes) in any combination will give only black puppies!
And now about the worst. As can be seen from the above examples, dominant black is not only able to hide the color of a dog formed by locus A and "mix up all the cards" in the classical pattern of inheritance of colors, it is phenotypically the most dominant color of all existing and, if appropriate measures are not taken, tends to wide progressive distribution in the breed.
Inheritance table of colors of the German shepherd, taking into account the dominant black gene for locus K
In addition, dominant black shepherd dogs rarely have a pure solid color. Most often, with age, their undercoat acquires a brownish-grayish tint, and noticeably lightened areas appear in the tan areas, in the groin, and often on the neck, thighs, in the shoulder area and even along the body. This is not surprising - the expression of the K gene is not always enough to hide the colors of the agouti locus under its eumelanin "veil". And it will never be possible to get rid of these pigmentation problems in dominant blacks ... As a result, their owners are already beginning to master the tricks of the modern pet industry, more and more dyed black dogs appear at exhibitions ... Is this what we would like for our breed?
Впрочем, вопрос риторический, больше волнующий тех заводчиков, которые остались верны породным традициям и не пошли на поводу у моды. Они же, в первую очередь обеспокоены вопросами, связанными с появлением гена доминантного черного окраса в породе. Кем и когда была сделана та роковая вязка? Была ли она случайной или целенаправленной? Собаки каких пород послужили исходным материалом для этих экспериментов? Сколько поколений прошло с тех пор? И что делать дальше с этим, уже довольно большим по численности поголовьем? Все эти вопросы пока еще остаются открытыми. Но рано или поздно они потребуют ответа.
In the meantime ... while we are forced to observe how enterprising admirers of the dominant black color continue to "stamp" puppies in demand in our market and listen "far-fetched" arguments about its appearance in the breed - they say, mutation ... or preservation gene K in individual blood lines since the founding of the breed, which for more than a hundred years has gone unnoticed! Even the nickname of one of the German breeders of the 50s is called, which allegedly had a dominant black color and gave black puppies in each litter. But the fact that almost all the livestock of those years were heterozygous for the black recessive color is somehow not given importance ... And all these arguments, against the background of a surprised question - How did the dominant blacks prevent you? Yes, in fact, nothing, except for one thing - they are not purebred.
In this regard, it is worth remembering that the German Shepherd has always belonged to the purebred breeds. That is, for its creation, improvement and reproduction, dogs of other breeds have never been used and the pedigrees of modern German shepherds can be traced back to its ancestors - this is what, according to zootechnical standards, distinguishes a purebred breed from a purebred one. A true breeder cannot ignore this fact. In addition, the homeland of this breed is Germany, which has the prerogative in addressing such important issues as the expediency of adding other bloodlines, changing the standard and compliance with other important characteristics, which undoubtedly include the genome of the population. For now, the Germans shrug their shoulders in bewilderment when they hear about the miracles of genetics taking place in Russia, Ukraine, Belarus with their national breed. While not yet understanding the scale of this phenomenon, they recommend doing a DNA analysis for the reliability of the origin, having heard about the next black phenomenon. But this is for now. Until the black dominants got into the breeding of SVs and did not affect their national interests ... It is difficult to say what will happen next. Will the luminaries of the breed want to adopt a different genetics and transfer the German Shepherd from the category of purebred breeds to the category of conditionally purebred? Or would they prefer to put the dominant blacks out of the breed with one stroke of the pen? And won't there be another breed group after that, not recognized by the FCI? Time will show... It's hard to say what will happen next. Will the luminaries of the breed want to adopt a different genetics and transfer the German Shepherd from the category of purebred breeds to the category of conditionally purebred? Or would they prefer to put the dominant blacks out of the breed with one stroke of the pen? And won't there be another breed group after that, not recognized by the FCI? Time will show... It's hard to say what will happen next. Will the luminaries of the breed want to adopt a different genetics and transfer the German Shepherd from the category of purebred breeds to the category of conditionally purebred? Or would they prefer to put the dominant blacks out of the breed with one stroke of the pen? And won't there be another breed group after that, not recognized by the FCI? Time will show...
In conclusion, I want to quote a paragraph from the wonderful and extremely useful for all breeders book by Larisa Pasechnik "Dog Colors", which, as it seems to me, can be put as an epilogue to all these arguments:
In the pedigrees of dogs, completely strange names of colors suddenly begin to appear, under the motto of poetic and national characteristics in terminology. It is impossible to understand what color is meant without seeing the dog, and by a strange coincidence, the dogs are more and more unknown, and neither the photos nor the dogs themselves can already be seen. Nevertheless, in some places there are obvious blunders and, if desired, it is quite possible to get to the bottom of the truth. It's just that hardly anyone wants to dig into it.
And yet, sooner or later it will happen. Genetics is still a science, and a wonderful science. Now with might and main is the study of mitochondrial DNA of many biological species, including dogs. Mitochondria - large organelles located in the cytoplasm of the cell, provide cellular respiration, and, in addition, are carriers of genetic information. It turns out that not all hereditary information is concentrated in chromosomes, but only slightly more than 90%, the rest of the information is contained in mitochondrial genes, as well as in small cellular inclusions, often of an infectious nature. The collection of cytoplasmic genes is referred to as "plasmon". Plasmogens are transmitted to descendants mainly through the maternal line, because sperm have a negligible amount of plasmagens. This feature,
In the future, it is possible to compile a complete family tree of the species, with accurate answers to such exciting questions as the origin of each of the breeds, indicating the time of birth of the breed, ancestors, and even when crossing with other breeds and with which ones took place. Then the secret will become apparent, and the world will recognize its heroes. "
Lyudmila Arkhangelskaya, 2013
Using materials from the book by Larisa Pasechnik
"Colors of dogs. Genetic, biochemical and molecular biological aspects"
by kitkat3478 on 13 September 2021 - 17:09
Since I m looking for explanation,
Dominant blacks: ten years later
Ten years have passed since the first black German shepherd dogs appeared at Russian exhibitions after a long break, which attracted the attention of breeders. In this time interval there was everything: misunderstanding, doubts, the study of special literature, rejection and the search for truth. After all, only the form was understandable, the content raised many questions. But I will not repeat myself, all this is in my first article About the black color of the German Shepherd, written in 2013. Today I want to take stock and make cautious forecasts for the future.
The fact that the black color of these dogs, which unexpectedly appeared in a breed that has a hundred-year history, is atypical for it and is inherited according to the dominant type, seems to be clear to everyone today. And the time of controversy - where he came from, is long gone. Today this is no longer of fundamental importance. Today we are faced with the fact that with the connivance of our canine organizations, dominant black dogs have spread widely in the breed and have found their admirers even among the leading breeders. The first such dogs have already come to Germany and are successfully exhibited at the German Sieger, which, of course, does not mean that the Germans recognized these dogs. Before the official recognition and choice of priorities, which sooner or later will have to be done by the "keepers" of the breed standard, is still far away. First they have to go the same way
What do we have after ten years of active use of dominant blacks?
From the pros - we must pay tribute to their breeders - we have externally beautiful dogs. But this is not surprising, given the dominant type of inheritance and selection for quality, which was carried out these years with the active use of top producers.
Of the minuses - problems with color, which, no matter how they tried to hide, still became obvious. Now everyone knows that a very small percentage of dogs born with dominant blacks retain their true black color for life. Most of them “change color” with age, turning into “silver fox” of varying degrees of intensity, and this is already a phenotypic non-compliance with the standard. Although, from the point of view of genetics, the word “out-color” is not entirely correct, in this case the wool does not over-color, other processes take place, which will be discussed below.
So, the minus turned out to be very unpleasant. These are problems at exhibitions, where experts reject "silver fox", and unfulfilled hopes, and conflicts with buyers, and the sale of "suspicious" puppies on a sofa (or on a chain), and fraud attempts, in the form of using all kinds of dyes and sprays. And the logical question is how to avoid “overcoloration”?
H is the most curious, so far I have met an answer to this question only in the circle of lovers of other breeds, or in specialized communities where talking genetics, and never heard an explanation from the breeders of German shepherds, not to mention the fact, to see a reasonable program breeding aimed at solving this problem. I don’t want to say that there are no people who are informed and knowledgeable in genetics among the “Germans”, probably the reason for everything is commercial interests. After all, it is known that it is easier to “fish in troubled water”.
Personally, I have never answered this question for another reason - I did not consider this part of the population purebred and did not support its development. But over time, an understanding came - if this process cannot be stopped, then you can at least try to direct it in the right direction. I am far from thinking that I personally will be able to do this - hope for breeders, for whom the concept of "breed interests" is not an empty phrase.
But before talking about how it is possible to get rid of the "silver fox" in the population of dominant blacks, it should be reminded once again how the dominant black color - atypical for the German shepherd breed - differs from its "native" recessive black.
To begin with, it is important to understand that color is not a static sign, it is formed under the influence of biochemical reactions in the cells of the body. And even color-forming genes do not directly affect the formation of color, they only store information for the intracellular structures that carry out these reactions. Thus, two seemingly identical colors can be formed by completely different biochemical reactions, information about which is stored in different loci, in different parts of DNA.
The German Shepherd Dog is one of the few breeds where all standard colors are formed by the A locus. This is the most important locus responsible for the production of agouti proteins in dogs and the formation of natural colors necessary for the adaptation of the species to the environment. If dogs did not have agouti proteins, they would all be black, formed by the action of the E gene, which is responsible for the normal distribution of pigment. The genes at the A locus work in close relationship with the E gene, giving a pulsating signal for alternating between the production of black and red pigments. As a result of this interaction, the line of agouti colors looks like this (according to the degree of dominance):
dominant red (gene ay) - there is no German Shepherd of this color
zonal (aw gene)
black and tan (at gene)
recessive black (gene a)
The recessive black color is formed due to the inactive form of agouti proteins. Here, by the way, it is worth paying attention to the clarification, which sometimes occurs in recessive black dogs in the tan areas. At a time when there was still no scientific research in this area, breeders of German shepherds considered such dogs tan or "blackened" zonal, which of course is not true. It is also wrong to talk about the "weakening" of the black color, which is often heard today, especially in the context of the dispute about the "overcoloration" of dominant blacks. This phenomenon is of a completely different order, it indicates the activity of agouti proteins, which try to suppress the synthesis of black pigment.
But back to dominant blacks. The bottom line is that the nature of the formation of black color in these dogs is different. Locus K is responsible for the production of defensin proteins, which provide the body's immune defense. It is represented by three genes:
dominant eumelanin color (gene K)
color with eumelanine stripes or brindle color (kbr gene)
recessive gene for normal distribution of eumelanin (gene ky or k)
Although, according to some sources, kbr is not an independent gene, but a duplication (doubling) of the ky gene, in the context of this topic it is not of fundamental importance.
If a dog has the recessive allele kyky (kk), normal production of defensins occurs, which does not prevent the appearance of the colors of the A locus. All German Shepherds of standard colors at the K locus have the kyky allele.
The kbr gene causes an increased production of defensins, which is reflected in the appearance of eumelanin stripes in the dog's color (brindle color).
In the presence of a dominant K gene at this locus, defensins are produced in large quantities, they are accumulated in cells and extracellular space, the dog turns completely black. Although the production of agouti proteins and biochemical processes at the A locus do not stop, the inheritance of the genes of this locus, however, like all others, occurs according to the usual pattern. Another thing is that due to the epistatic nature of the K gene, these processes turn out to be hidden from our eyes.
K-defensin is considered a product of a mutation, but it should be recognized that this is one of the few mutations that is not devoid of beneficial properties. In this sense, the dominant blacks can be congratulated - they have acquired increased immune protection compared to carriers of the recessive kyky allele. This, of course, is not a reason to take it literally - the ky gene perfectly does its job as an immune protein, and the greater reliability of K-defensins can only be said at the level of statistics, and not in each individual case.
Probably, already at this stage of reading the article, it becomes clear that the degree of staining of dominant black dogs is influenced by the intensity of production of K-defensins and the density of their accumulation in tissues . But that is not all.
The phenomenon that we call "overflow" in genetics is called the seal effect. It must be said right away that there is no deep scientific research in this area yet, but there are indirect studies, there are observations, there is an analysis of the selection of many other breeds for which the black dominant color is standard, there are, finally, the conclusions of professional geneticists described in the special literature and repeatedly expressed in various thematic forums. I am not "discovering America", I am simply sharing generalized information based on ten years of experience studying this topic.
So, the seal-effect in dominant blacks is not "overcoloration", it is the result of a decrease in protein production in the cells, as a result of which zones with a low concentration of K-defensin appear on the dog's coat . These zones do not have a specific localization, they can be small, formed in places of tanning, and can spread to the neck, body and even the head of the dog. What does it depend on?
There are different versions - about the influence of some unknown modifier gene, about the presence in the K locus of another, intermediate gene that causes the seal effect, but the most probable is still a simple explanation: the heterozygous Kky allele is not able to fully synthesize the protein, the efforts of the cell that uses only one chromosome with a dominant allele is not enough to fight E-receptors. As a result, in areas with a low concentration of K-defensin, color appears due to the agouti locus.
This confirms the fact that most breeds in which the seal effect occurs can have a heterozygous black color, and in most breeds where the dominant black color is homozygous for a long time this effect is not observed. Exceptions, of course, are possible, but each of them has its own explanation. In particular, we know that in the German Shepherd breed there are unwanted recessive genes belonging to other loci that, in a homozygous state, can affect the formation of color: dd - blue color, bb - brown, ii - lightening of tan to whitish. Dogs - carriers of such alleles will demonstrate a seal effect regardless of the combination of genes at locus A. This also applies to the brownish tint of the coat, which may be due to completely different factors.
In the German Shepherd breed, most of the dogs that have been “out of color” and tested are heterozygotes at the K locus, which is to be expected.
It is easy to guess that the seal-effect can be manifested to a greater extent in dogs with lighter colors at locus A, with pronounced pheomelanin zones:
zonal homozygous (awaw)
zoned heterozygous with the black-backed gene (awat)
black-backed homozygous (atat)
to a lesser extent, it can manifest itself in dogs with colors with more pronounced eumelanin zones:
zoned heterozygous with the gene for black color (awa)
black-backed heterozygous with the gene for black color (ata)
Dogs with the so-called "double" black color (Kk - at the K locus, aa - at the A locus) theoretically should not be subject to the seal effect at all, but there are no data on testing such dogs at the moment.
What conclusion can be drawn from all of the above? Very simple: there are only two ways to avoid the massive manifestation of the seal effect in the population of dominant blacks. The first is to breed dogs of "double" black color, but it is impossible due to the absence of recessive blacks in the show population. The second - more real, and today already feasible - is to transfer the black color to a homozygous state, localizing it within the same population, by mating black dogs only among themselves. In this way, already in the first generation, when mating two heterozygous dogs, it will be possible to obtain a part of homozygous puppies that are not prone to the manifestation of the seal effect, and with each subsequent generation to increase this percentage, which is impossible when mating blacks with black-backed or zonal partners.
This is the only way to rid the population of dominant blacks from non-standard "silver fox" and to protect yourself in case something goes wrong in the homeland of the breed with the use of these dogs. Then it will be possible to remember that there is, after all, a white Swiss shepherd dog, why not appear in the list of breeds also a black Russian?
By the way, the very widespread opinion that the mating of black dogs among themselves leads to degeneration, thinning of the skeleton, lengthening of the heads is an absolute delusion. Color loci are in no way associated with loci that encode information about the anatomical structure of dogs. This misconception is based on an incorrect conclusion when considering the cases in which there was a founder effect, when a small number of dogs of the same color turned out to be related to a sire with certain disadvantages fixed in the population. Dominant blacks are not in danger. Firstly, due to the fact that the “founders”, as we know, were far from “thin and sonorous”, and secondly, because for ten years there was no separate breeding and this population is not so homogeneous , both by genotype and phenotype,
I think I am not alone in my reflections, because it is not for nothing that there has recently been a clear tendency among breeders of dominant blacks to search for homozygous sires.
And a few more words about tests. Now it has become fashionable to do testing, but for the most part people themselves do not understand what they are testing and for what purpose. In most cases, tests for the presence of certain alleles in the German Shepherd breed are meaningless, since everything is read by the dog's pedigree, which is easy to generate in pedigreedatabase.com or working-dog.com
Testing makes sense only in a few cases:
when there is no initial data to determine homozygosity or heterozygosity of a dog for locus A or locus K (a test is done simultaneously for two loci A and K)
when, when mating a dominant black dog with a recessive black dog, it becomes necessary to identify the genotype of puppies (a test is done simultaneously at two loci A and K)
when a dog has a seal effect, which logically should not have it and there is a suspicion that recessive genes of other loci, for example d or b, have intervened in the color-forming process (a test is done for loci A, B, D, K)
when the origin of the dog is in doubt (as appropriate)
In conclusion, a few theses on the topic:
The seal effect in black dogs is more pronounced with the genotype:
awawKky - black heterozygous for locus K and zonal homozygous for locus A
awatKky - black heterozygous at the K locus and zonal heterozygous at the A locus with the black-backed gene
atatKky - black heterozygous at the K locus and black-backed homozygous at the A locus
The seal effect in black dogs is less pronounced with the genotype:
awaKky - black heterozygous at the K locus and zonal heterozygous with the black gene at the A locus
ataKky - black heterozygous at the K locus and black-backed / black and tan heterozygous with the black gene at the A locus
The seal effect in black dogs is not manifested in the genotype:
aaKkyy - black heterozygous at the K locus and black homozygous at the A locus ("double" black)
- - KK - black homozygous for locus K and any combination of genes for locus A
Homozygous dominant blacks (CC), not prone to the seal effect, are born from only two dominant blacks:
from two heterozygotes approximately 25% of puppies:
KKy + KKy = KK + KKy + KKy + kyky
from heterozygote and homozygote approximately 50% of puppies:
KKy + KK = KK + KK + KKy + KKy
from two homozygotes - 100% of puppies:
QC + QC = QC + QC + QC + QC
Homozygous dominant blacks (CC) from mating a dominant black dog (even if it is homozygous) with a sonal or black-backed partner cannot be born:
KKy + kyky = KKy + KKy + kyky + kyky
KK + kyky = KKy + KKy + KKy + KKy
And the last thing. After the publication of this article, I foresee a flurry of questions and objections on the topic "but I have ..." In the article I have already written about the reasons why theory may diverge from practice, in addition to these, there are others. Physically, I will not be able to make out all your pedigrees in order to make an analysis for each of them and understand why, somewhere, something does not agree with the theory. In addition, this is not always possible due to incomplete input data. You, as breeders, have more complete information on each of your dogs - you have the cards in your hands. There are no questions to which an inquiring human mind cannot find answers. To help I can recommend the wonderful book by L. Pasechnik “Dog Colors. Genetic, biochemical and molecular biological aspects " - in it, upon detailed study, you will find answers to many questions that arise, and I hope, make sure that, in general, this theory is correct.
Lyudmila Arkhangelskaya, 2019
All about the German Shepherd
author's site of Lyudmila Arkhangelskaya
Site author - Arkhangelskaya Lyudmila Nikolaevna
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Dominant blacks: ten years later
Ten years have passed since the first black German shepherd dogs appeared at Russian exhibitions after a long break, which attracted the attention of breeders. In this time interval there was everything: misunderstanding, doubts, the study of special literature, rejection and the search for truth. After all, only the form was understandable, the content raised many questions. But I will not repeat myself, all this is in my first article About the black color of the German Shepherd, written in 2013. Today I want to take stock and make cautious forecasts for the future.
The fact that the black color of these dogs, which unexpectedly appeared in a breed that has a hundred-year history, is atypical for it and is inherited according to the dominant type, seems to be clear to everyone today. And the time of controversy - where he came from, is long gone. Today this is no longer of fundamental importance. Today we are faced with the fact that with the connivance of our canine organizations, dominant black dogs have spread widely in the breed and have found their admirers even among the leading breeders. The first such dogs have already come to Germany and are successfully exhibited at the German Sieger, which, of course, does not mean that the Germans recognized these dogs. Before the official recognition and choice of priorities, which sooner or later will have to be done by the "keepers" of the breed standard, is still far away. First they have to go the same way
What do we have after ten years of active use of dominant blacks?
From the pros - we must pay tribute to their breeders - we have externally beautiful dogs. But this is not surprising, given the dominant type of inheritance and selection for quality, which was carried out these years with the active use of top producers.
Of the minuses - problems with color, which, no matter how they tried to hide, still became obvious. Now everyone knows that a very small percentage of dogs born with dominant blacks retain their true black color for life. Most of them “change color” with age, turning into “silver fox” of varying degrees of intensity, and this is already a phenotypic non-compliance with the standard. Although, from the point of view of genetics, the word “out-color” is not entirely correct, in this case the wool does not over-color, other processes take place, which will be discussed below.
So, the minus turned out to be very unpleasant. These are problems at exhibitions, where experts reject "silver fox", and unfulfilled hopes, and conflicts with buyers, and the sale of "suspicious" puppies on a sofa (or on a chain), and fraud attempts, in the form of using all kinds of dyes and sprays. And the logical question is how to avoid “overcoloration”?
H is the most curious, so far I have met an answer to this question only in the circle of lovers of other breeds, or in specialized communities where talking genetics, and never heard an explanation from the breeders of German shepherds, not to mention the fact, to see a reasonable program breeding aimed at solving this problem. I don’t want to say that there are no people who are informed and knowledgeable in genetics among the “Germans”, probably the reason for everything is commercial interests. After all, it is known that it is easier to “fish in troubled water”.
Personally, I have never answered this question for another reason - I did not consider this part of the population purebred and did not support its development. But over time, an understanding came - if this process cannot be stopped, then you can at least try to direct it in the right direction. I am far from thinking that I personally will be able to do this - hope for breeders, for whom the concept of "breed interests" is not an empty phrase.
But before talking about how it is possible to get rid of the "silver fox" in the population of dominant blacks, it should be reminded once again how the dominant black color - atypical for the German shepherd breed - differs from its "native" recessive black.
To begin with, it is important to understand that color is not a static sign, it is formed under the influence of biochemical reactions in the cells of the body. And even color-forming genes do not directly affect the formation of color, they only store information for the intracellular structures that carry out these reactions. Thus, two seemingly identical colors can be formed by completely different biochemical reactions, information about which is stored in different loci, in different parts of DNA.
The German Shepherd Dog is one of the few breeds where all standard colors are formed by the A locus. This is the most important locus responsible for the production of agouti proteins in dogs and the formation of natural colors necessary for the adaptation of the species to the environment. If dogs did not have agouti proteins, they would all be black, formed by the action of the E gene, which is responsible for the normal distribution of pigment. The genes at the A locus work in close relationship with the E gene, giving a pulsating signal for alternating between the production of black and red pigments. As a result of this interaction, the line of agouti colors looks like this (according to the degree of dominance):
dominant red (gene ay) - there is no German Shepherd of this color
zonal (aw gene)
black and tan (at gene)
recessive black (gene a)
The recessive black color is formed due to the inactive form of agouti proteins. Here, by the way, it is worth paying attention to the clarification, which sometimes occurs in recessive black dogs in the tan areas. At a time when there was still no scientific research in this area, breeders of German shepherds considered such dogs tan or "blackened" zonal, which of course is not true. It is also wrong to talk about the "weakening" of the black color, which is often heard today, especially in the context of the dispute about the "overcoloration" of dominant blacks. This phenomenon is of a completely different order, it indicates the activity of agouti proteins, which try to suppress the synthesis of black pigment.
But back to dominant blacks. The bottom line is that the nature of the formation of black color in these dogs is different. Locus K is responsible for the production of defensin proteins, which provide the body's immune defense. It is represented by three genes:
dominant eumelanin color (gene K)
color with eumelanine stripes or brindle color (kbr gene)
recessive gene for normal distribution of eumelanin (gene ky or k)
Although, according to some sources, kbr is not an independent gene, but a duplication (doubling) of the ky gene, in the context of this topic it is not of fundamental importance.
If a dog has the recessive allele kyky (kk), normal production of defensins occurs, which does not prevent the appearance of the colors of the A locus. All German Shepherds of standard colors at the K locus have the kyky allele.
The kbr gene causes an increased production of defensins, which is reflected in the appearance of eumelanin stripes in the dog's color (brindle color).
In the presence of a dominant K gene at this locus, defensins are produced in large quantities, they are accumulated in cells and extracellular space, the dog turns completely black. Although the production of agouti proteins and biochemical processes at the A locus do not stop, the inheritance of the genes of this locus, however, like all others, occurs according to the usual pattern. Another thing is that due to the epistatic nature of the K gene, these processes turn out to be hidden from our eyes.
K-defensin is considered a product of a mutation, but it should be recognized that this is one of the few mutations that is not devoid of beneficial properties. In this sense, the dominant blacks can be congratulated - they have acquired increased immune protection compared to carriers of the recessive kyky allele. This, of course, is not a reason to take it literally - the ky gene perfectly does its job as an immune protein, and the greater reliability of K-defensins can only be said at the level of statistics, and not in each individual case.
Probably, already at this stage of reading the article, it becomes clear that the degree of staining of dominant black dogs is influenced by the intensity of production of K-defensins and the density of their accumulation in tissues . But that is not all.
The phenomenon that we call "overflow" in genetics is called the seal effect. It must be said right away that there is no deep scientific research in this area yet, but there are indirect studies, there are observations, there is an analysis of the selection of many other breeds for which the black dominant color is standard, there are, finally, the conclusions of professional geneticists described in the special literature and repeatedly expressed in various thematic forums. I am not "discovering America", I am simply sharing generalized information based on ten years of experience studying this topic.
So, the seal-effect in dominant blacks is not "overcoloration", it is the result of a decrease in protein production in the cells, as a result of which zones with a low concentration of K-defensin appear on the dog's coat . These zones do not have a specific localization, they can be small, formed in places of tanning, and can spread to the neck, body and even the head of the dog. What does it depend on?
There are different versions - about the influence of some unknown modifier gene, about the presence in the K locus of another, intermediate gene that causes the seal effect, but the most probable is still a simple explanation: the heterozygous Kky allele is not able to fully synthesize the protein, the efforts of the cell that uses only one chromosome with a dominant allele is not enough to fight E-receptors. As a result, in areas with a low concentration of K-defensin, color appears due to the agouti locus.
This confirms the fact that most breeds in which the seal effect occurs can have a heterozygous black color, and in most breeds where the dominant black color is homozygous for a long time this effect is not observed. Exceptions, of course, are possible, but each of them has its own explanation. In particular, we know that in the German Shepherd breed there are unwanted recessive genes belonging to other loci that, in a homozygous state, can affect the formation of color: dd - blue color, bb - brown, ii - lightening of tan to whitish. Dogs - carriers of such alleles will demonstrate a seal effect regardless of the combination of genes at locus A. This also applies to the brownish tint of the coat, which may be due to completely different factors.
In the German Shepherd breed, most of the dogs that have been “out of color” and tested are heterozygotes at the K locus, which is to be expected.
It is easy to guess that the seal-effect can be manifested to a greater extent in dogs with lighter colors at locus A, with pronounced pheomelanin zones:
zonal homozygous (awaw)
zoned heterozygous with the black-backed gene (awat)
black-backed homozygous (atat)
to a lesser extent, it can manifest itself in dogs with colors with more pronounced eumelanin zones:
zoned heterozygous with the gene for black color (awa)
black-backed heterozygous with the gene for black color (ata)
Dogs with the so-called "double" black color (Kk - at the K locus, aa - at the A locus) theoretically should not be subject to the seal effect at all, but there are no data on testing such dogs at the moment.
What conclusion can be drawn from all of the above? Very simple: there are only two ways to avoid the massive manifestation of the seal effect in the population of dominant blacks. The first is to breed dogs of "double" black color, but it is impossible due to the absence of recessive blacks in the show population. The second - more real, and today already feasible - is to transfer the black color to a homozygous state, localizing it within the same population, by mating black dogs only among themselves. In this way, already in the first generation, when mating two heterozygous dogs, it will be possible to obtain a part of homozygous puppies that are not prone to the manifestation of the seal effect, and with each subsequent generation to increase this percentage, which is impossible when mating blacks with black-backed or zonal partners.
This is the only way to rid the population of dominant blacks from non-standard "silver fox" and to protect yourself in case something goes wrong in the homeland of the breed with the use of these dogs. Then it will be possible to remember that there is, after all, a white Swiss shepherd dog, why not appear in the list of breeds also a black Russian?
By the way, the very widespread opinion that the mating of black dogs among themselves leads to degeneration, thinning of the skeleton, lengthening of the heads is an absolute delusion. Color loci are in no way associated with loci that encode information about the anatomical structure of dogs. This misconception is based on an incorrect conclusion when considering the cases in which there was a founder effect, when a small number of dogs of the same color turned out to be related to a sire with certain disadvantages fixed in the population. Dominant blacks are not in danger. Firstly, due to the fact that the “founders”, as we know, were far from “thin and sonorous”, and secondly, because for ten years there was no separate breeding and this population is not so homogeneous , both by genotype and phenotype,
I think I am not alone in my reflections, because it is not for nothing that there has recently been a clear tendency among breeders of dominant blacks to search for homozygous sires.
And a few more words about tests. Now it has become fashionable to do testing, but for the most part people themselves do not understand what they are testing and for what purpose. In most cases, tests for the presence of certain alleles in the German Shepherd breed are meaningless, since everything is read by the dog's pedigree, which is easy to generate in pedigreedatabase.com or working-dog.com
Testing makes sense only in a few cases:
when there is no initial data to determine homozygosity or heterozygosity of a dog for locus A or locus K (a test is done simultaneously for two loci A and K)
when, when mating a dominant black dog with a recessive black dog, it becomes necessary to identify the genotype of puppies (a test is done simultaneously at two loci A and K)
when a dog has a seal effect, which logically should not have it and there is a suspicion that recessive genes of other loci, for example d or b, have intervened in the color-forming process (a test is done for loci A, B, D, K)
when the origin of the dog is in doubt (as appropriate)
In conclusion, a few theses on the topic:
The seal effect in black dogs is more pronounced with the genotype:
awawKky - black heterozygous for locus K and zonal homozygous for locus A
awatKky - black heterozygous at the K locus and zonal heterozygous at the A locus with the black-backed gene
atatKky - black heterozygous at the K locus and black-backed homozygous at the A locus
The seal effect in black dogs is less pronounced with the genotype:
awaKky - black heterozygous at the K locus and zonal heterozygous with the black gene at the A locus
ataKky - black heterozygous at the K locus and black-backed / black and tan heterozygous with the black gene at the A locus
The seal effect in black dogs is not manifested in the genotype:
aaKkyy - black heterozygous at the K locus and black homozygous at the A locus ("double" black)
- - KK - black homozygous for locus K and any combination of genes for locus A
Homozygous dominant blacks (CC), not prone to the seal effect, are born from only two dominant blacks:
from two heterozygotes approximately 25% of puppies:
KKy + KKy = KK + KKy + KKy + kyky
from heterozygote and homozygote approximately 50% of puppies:
KKy + KK = KK + KK + KKy + KKy
from two homozygotes - 100% of puppies:
QC + QC = QC + QC + QC + QC
Homozygous dominant blacks (CC) from mating a dominant black dog (even if it is homozygous) with a sonal or black-backed partner cannot be born:
KKy + kyky = KKy + KKy + kyky + kyky
KK + kyky = KKy + KKy + KKy + KKy
And the last thing. After the publication of this article, I foresee a flurry of questions and objections on the topic "but I have ..." In the article I have already written about the reasons why theory may diverge from practice, in addition to these, there are others. Physically, I will not be able to make out all your pedigrees in order to make an analysis for each of them and understand why, somewhere, something does not agree with the theory. In addition, this is not always possible due to incomplete input data. You, as breeders, have more complete information on each of your dogs - you have the cards in your hands. There are no questions to which an inquiring human mind cannot find answers. To help I can recommend the wonderful book by L. Pasechnik “Dog Colors. Genetic, biochemical and molecular biological aspects " - in it, upon detailed study, you will find answers to many questions that arise, and I hope, make sure that, in general, this theory is correct.
Lyudmila Arkhangelskaya, 2019
All about the German Shepherd
author's site of Lyudmila Arkhangelskaya
Site author - Arkhangelskaya Lyudmila Nikolaevna
about the author
Contact via Faceboock
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by Hundmutter on 14 September 2021 - 15:09
KitKat, thanks for getting this translation - I'm taking it that this IS the translation Lottas suggested was necessary, not something else entirely ?
Seems to me there are some gaping holes in Lyudmila's book &/or interpretation, however. Maybe this is some direct result of the restrictions of the old Soviet system, in making it less easy for Russian authors to access books on the GSD from the West ?
She seems to argue that until the appearance of Pharoah, Eustace and Shaitan, they 'never' saw an all-black GSD. BS. Must have been around, even if not numerous or popular. The breed worldwide did not begin in the 1980s with 'red' tan & Dog Shows. She discusses dilution of colour genetics, but only in the context of 'rare' blues - well, they may have been literally culling those in the Eastern Bloc, but she surely cannot be unaware of the huge numbers bred deliberately in the States and UK (if not all Europe) for the pet market ? You used to have Blues, you must know that what I am saying is true ? And what about the Livers ? And why is White not mentioned at all ?
It really does not assist understanding that her/their 4 Standard colours apparenty ain't the same, even allowing for translation error, as the rest of the world's. Talks about the importance of agouti - but no mention of Sables / greys ???
I may come back on this as I have not ploughed thru it all yet, curious to see EXACTLY what she claims for the K allele - but just had to get the above off my chest before going further ...
by hexe on 14 September 2021 - 23:09
Hundmutter, my understanding of the material, after reading through what kitkat posted, is that the term 'zonal' is a translation of a Russian word that most likely equates to sable.
That said, I still remain unconvinced that these Russian showline 'dominant black' dogs aren't carrying genetics acquired from another breed or landrace
That said, I still remain unconvinced that these Russian showline 'dominant black' dogs aren't carrying genetics acquired from another breed or landrace
by Hundmutter on 15 September 2021 - 02:09
Hexe, I was taking 'zonal' as 'solid', so all-black (rather than 'mostly black' ie Bi-colour !). But you could well be right.
You could also be correct about genes from some other breed being introduced.
Though if that is the case, I'd be even more reluctant to accept the insistence of some that these are an improvement on proper purebred GSD and therefore to be sought out / bred on ! Basically I am not completely opposed to an infusion of 'new' blood to the breed IF THERE ARE STRONG REASONS FOR DOING SO - a colour gene, seemingly mostly for Show purposes on the Russian scene, would not seem to fit that criteria.
by Rik on 15 September 2021 - 08:09
me trying to digest and discuss all that would be no different than me trying to discuss brain surgery. so I won't even play like I understand it.
the main part I think I did get is that the Russian black is a different gene than discovered in the GSD before. if that's so then it doesn't rule out that there were some russian dogs and GSD that might have been very friendly.
regardless, if the dogs registration is accepted in other countries, probably makes little difference at this point.
the main part I think I did get is that the Russian black is a different gene than discovered in the GSD before. if that's so then it doesn't rule out that there were some russian dogs and GSD that might have been very friendly.
regardless, if the dogs registration is accepted in other countries, probably makes little difference at this point.
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