reversed mask - Page 4

The great breeder Alfred Hahn of BuseckerSchlob kennel, always maintained he found GS with lighter eyes had a better working aptitude. I probably would trust his opinion over any of my friends of today...lol   Anyway, Duke I know you are going to do the right thing, and if I thought you would not use an acceptable color pattern if it would bring the traits needed to keep your program sound, because of " likes", I would lose a lot of respect for you breeding wise.

seems a lot of people are making a lot of very testable hypotheses (or whatever the plural of hypothesis is), would be a simple study that may well save the breed;

reverse masks/lighter coloured eyes CAUSE balanced drives and general super-duper awesomeness in the progeny.

given these dogs are "pre-potent" then you should see an observable effect on lines that have a known history of poor nerves, poor drives etc, etc as well as an observable effect on known good lines. a simple outcross to a reverse mask parent into solid blacks or black & tans, will do it.

I say all the folks that make money from breeding dogs pool some funds and put your inheritable colour linked genetic working traits claim to a formal scientifc study and possibly make the biggest positive impact on the breed in it's entire history - working kelpie breeders did exactly that and there is a lot more GSD's being bred and sold for ridiculous money than kelpies.

so have at it, get some science.

Most people have a Favorite Color or Color Pattern...Is it the #1 thing on my Priority List?...My list goes something like this:

*Working Ability: High...Balanced Drives

*Temperament

*Healthy: Hips...Elbows...etc.

*Good Looking

*Color

I think the gene pool for the Working German Shepherd needs to stay as open as possible...It seems the gene pool for Working German Shepherds gets more and more shallow...The "Reverse Mask" might or might not be my favorite color but if the dog possesses all the abilities that I want...then I would want him/her for my personal dog...

I also think this is a very good "open" discussion that is the kind that ought to be talked about on this site...

 

~Bob~

 

I haven't found anything thus far about the genetics of the reversed mask but it must not be a simple dominant or recessive gene or there would be far more of them.  The reversed mask is most likely a multiple allele with a block inheritance or linkage to another trait.  In genetics they call this incomplete penetrance or in other words "we don't know".  That might explain the trait sometimes appearing dominant in some cases while still being a rare coat pattern.  I suspect reversed mask is similar to rear dew claws in the GSD which is also a trait that does not show a clear pattern of inheritance.  I once had a litter from a sire and dam with dew claws and none of the puppies had dew claws.  I suspect that reverse mask trait is linked to an environmental or genetic factor that occurs during embryo development which interrupts normal coat pattern expression.  If anyone has better information on either reverse mask or dew claws please speak up.  Of course in the case of dew claws the expression is variable within a litter even with some puppies having no rear dew claws, some with only one rear, some with two and even some with one or two rear double dew claws.  In some breeds ( Great Pyrenees ) the presence of double dew claws is a required breed characteristic.  I wonder if variable expression is seen in the reversed mask or I think we know that mask type is quite variable which most likely also suggests a method of genetic control that is multiple allele.

VetGen DNA CHROMAGENE Coat Color Testing

For many years geneticists and breeders have been aware of several locations on the chromosomes, or loci, which are responsible for the color patterns we see in dogs and other mammals. As with all genetic traits, every animal inherits one copy of each locus from each of its parents. Each of these loci is responsible for one or more traits either independently, or in conjunction with another locus. All of them act on the pathways that produce the two major pigments, phaeomelanin and eumelanin, or affect the distribution of those pigments.

The combined effect of all these loci (Agouti, Brown, Extension, etc.) is the color of the dog. Due to the complex interactions of these genes, it is possible for dogs to carry hidden colors which may appear in their offspring. Over the past several years, scientists at VetGen and elsewhere have determined the actual genes associated with many of these loci, and identified the mutations responsible for the different versions (alleles) of these genes. The fruit of this work are the tests available for many of the common coat colors and traits.

The diagram below illustrates the relationships among the major loci (A, B, E and K) involved in determining coat color. The sections that follow describe the role these loci and others play in the coat color tests that VetGen offers. These tests demonstrate that while a dog may exhibit certain color or colors, it may also be carrying other hidden colors in its genetic code that can show up in later generations.

How do the A, B, E, and K loci affect each other in determining coat color?

The accompanying graphic helps to illustrate the interactions of the genes at these four loci in a hierarchy in terms of their role in coat color. If a circle is filled with color, it means the color of the dog has been determined at that point. If a circle is still white, it means information about an additional gene is required.

The first locus to look at is the E locus. The gene at this locus is responsible for black masks when present as well as most shades of yellow and red. Any dog that is "ee" will be some shade of yellow to red, and everything happening at the A, B, and K loci will be hidden until the next generation. If the dog has any E or E^m alleles, then it will not be yellow and we must look next at the K locus.

There are three versions, or alleles, of the K locus: K^B, k^br, and k^y. If a dog has even a single copy of K^B (K^BK^B, K^Bk^y, K^Bk^br) it will be solid colored in the pigmented areas, and we go directly to the B locus to determine color. Everything happening at the A locus in these dogs is hidden until the next generation. If a dog is k^yk^y, it will not be brindled, and we go next to the A locus to see which alleles are expressed. If a dog is k^brk^br, or k^brk^y, it will nearly always be brindled and we look next at the A locus to see the background color and pattern of that brindling.

The A locus has at least four alleles. There are direct tests available for A^y (fawn or sable),"a" (recessive black), and "a^t" (tan points). There is no direct test for the Wild type (think wolf pattern) allele which is designated a^w.Any dog which has at least one copy of A^y (and no K^B) will be fawn or sable, either with or without brindling.Any dog that is "aa" (and no K^B) will be black. Any dog that is a^ta^t or a^ta (and no K^B) will have tan points, either with or without brindling.

The next stop is the B locus. Any dog which is "bb" will be have brown fur in those areas that would otherwise be black. This holds true for both solid colored and agouti-patterned animals.

The D locus (not shown in the diagram) can alter the intensity of pigment. Animals which are "dd" exhibit grey or blue fur in place of black, and light tan or "Isabella" in place of brown. This tan is similar to some A^Y shades but lacking any banding or black tips on individual hairs.

AVAILABLE TESTS

E locus

The E locus is responsible for the black mask seen in many breeds, and more significantly, for the presence of the yellow to red coats of many dogs. The gene involved is known as MC1-R, which has at least three versions affecting the appearance of the dog, E, E^m, and e. Dogs with two copies of e will be yellow, orange or red in their pigmented coat regardless of their genotype at all the other loci

Research at VetGen and independently at the University of Saskatchewan has identified two new alleles in the E locus, E^g and E^h. These mutations are responsible for a reverse mask or widow's peak appearance in the "domino" Afghan Hound and "grizzle" Saluki (E^g), as well as the "sable" English Cocker Spaniel (E^h). Research continues to determine if they are responsible for similar appearance in additional breeds.

Test for "e"

Analysis proves absence or presence of the mutation typically responsible for yellow, lemon, red, cream, apricot and some white in at least the following breeds and all dogs with these breeds in their lineage:

Afghan, Australian Cattle Dog, Australian Shepherd, Border Collie, Beagle, Brittany Spaniel, Cardigan Welsh Corgi, Chinese Shar-pei, Chow Chow, Cocker Spaniel, Dachshund, Dalmatian, Doberman Pinscher, English Cocker Spaniel, English Setter, English Springer Spaniel, Field Spaniel, Flat-Coated Retriever, Foxhound, French Bulldog, German Longhaired Pointer, German Shepherd, German Shorthaired Pointer, German Wirehaired Pointer, Irish Setter, Labrador Retriever, Lowchen, Pointer, Pomeranian, Poodle, Pudelpointer.

Test for E^m

Analysis reveals whether a dog with a mask has one or two copies of this version of the extension locus. Animals with a single copy can produce offspring with or without a mask, while those with two copies will only produce masked offspring. The test may also be applied to black dogs where it may not be possible to tell if there is a mask. It may be present in the following breeds and all dogs with them in their lineage:

Afghan, Belgian Shepherd, Boxer, Bull Mastiff, Cairn Terrier, Cardigan Welsh Corgi, Chihuahua, Chinese Shar-pei, English Bulldog,German Shepherd, Great Dane, Greyhound, Lakenois, Pekinese, Pug, Saint Bernard, Saluki, Staffordshire Bull Terrier,Whippet.

Test for E^g and/or E^h

Analysis reveals the absence or presence of the mutations responsible for "grizzle" in Salukis and "domino" in Afghans (E^g) or "sable" and "dirty red" in English Cocker Spaniels (E^h).

B Locus

The B locus is responsible for the presence of brown, chocolate, or liver animals. It is also responsible for nose color. The gene associated with this locus is known as TYRP1. In breeds where the A locus does not come into play, any animal that has at least one B allele (and is not "ee"), will be black in pigmented coat. Those dogs, which have two copies of any of several b alleles will be brown. There are at least three such b alleles. Regardless of other loci, any animal with at least one B allele will have a black nose and pads, while those with any two b alleles will have a liver nose and pads.

Test for b

This test analyzes whether an animal has 0, 1 or 2 copies of the mutations typically responsible for brown, which is also known in some breeds as liver, chocolate, sedge, and less frequently, red. There are three primary "b" mutations that are responsible for nearly every liver or chocolate dog. A notable exception is the French Bulldog where in addition to these three mutations, there is a fourth cause of chocolate that has yet to be identified.

It can be present at least, but not exclusively, in the following breeds:

Australian Cattle Dog, Australian Shepherd,Bedlington Terrier, Border Collie, Brittany Spaniel,Cardigan Welsh Corgi, Chihuahua, Chinese,Shar-pei, Cocker Spaniel, Curly Coated Retriever,Dachshund, Dalmatian, Doberman Pinscher,English Cocker Spaniel, English Setter,English Springer Spaniel,Field Spaniel, Flat-Coated Retriever, Fox Terrier, French Bulldog,German Longhaired Pointer, German Shorthaired Pointer, German Wirehaired Pointer,Labrador Retriever, Lowchen,Miniature Pinscher,Newfoundland Pointer, Pomeranian, Poodle, Portuguese Water Dog, Pudelpointer,Scottish Terrier, Skye Terrier,Weimaraner, Wirehaired Pointing Griffon.

Also:
Any dogs that contain these breeds in their lineage.

K Locus

The K locus plays a pivotal role in coat color. This locus is a relative newcomer in our understanding of canine color, and includes traits formerly attributed by some to other genes.

The dominant allele in the series is K^B, which is responsible for self-coloring, or solid colored fur in pigmented areas. This trait was formerly attributed to the Agouti (A) locus as A^S, but recent breeding studies had shown this not to be the case.

There are two other alleles, k^br, and k^y. K^B is dominant to both k^br and k^y, while k^br is dominant only to k^y. k^br is responsible for the brindle trait and for a long time had been considered to belong in the E locus. Recent breeding studies had also shown this to be incorrect. The recessive allele, k^y, allows the basic patterns of the A locus to be expressed. So too does the k^br allele, but with brindling of any tan, fawn, or tawny areas.

Any animal with at least one K^B allele will be self-colored.

Any animal with at least one k^br allele, and no K^B allele will be brindled on agouti background (see A locus).

Any animal with two k^y alleles will show agouti patterns (see A locus).

The mutations responsible for these alleles were identified and described primarily by Sophie Candille in the laboratory of Dr. Greg Barsh at Stanford University.

Test for K^B and k^y

Vetgen can presently test for these two alleles. In some breeds, where no brindle is present, this represents a complete analysis of the locus. An example would be the Pug. In breeds where the breed standard disqualifies all but self-colored dogs, testing for these two alleles is once again all that is needed. Any animal with two K^B alleles cannot produce anything except self-colored offspring. A prime example here is the Labrador retriever. In breeds where many variations are allowed, these tests can help predict the probability of potential litters to include fawn, sable, tawny, tan point, tricolor or recessive black puppies.

KB KB	self-colored (solid color in pigmented areas)
KB kbr	self-colored (solid color in pigmented areas)
KB ky	self-colored (solid color in pigmented areas)
kbr kbr	allows A locus to express (tan point, tricolor, fawn, sable, tawny) with brindling
kbr ky	allows A locus to express (tan point, tricolor, fawn, sable, tawny) with brindling
ky ky	allows expression of agouti patterns without brindling

A Locus

The A locus is responsible for a number of common coat patterns in the dog. Expression of all of them requires any combination of two k^y or K^br alleles at the K locus, and at least one E or E^m allele at the E locus.  The gene involved is the Agouti gene, and variations in it are responsible for fawn and sable dogs (A^y), wild type (a^w), tan points (a^t), and recessive black(a).

Test for A^y

Analysis proves absence or presence of the mutation typically responsible for fawn or sable. In fawn/ sable dogs this test shows if other agouti alleles are present but hidden (only one copy of A^y). It also demonstrates how many copies of this allele are hidden in dogs, which cannot express agouti types (K^BK^B, K^Bk^br, K^Bk^y, at the k locus and/or "ee" at the E locus).

Test for “a”

Analysis shows whether a black dog is black due to “recessive black,” or the more common black at the K locus. It also reveals whether a non-black animal carries “recessive black.”  Examples of breeds:

German Shepherd Dog, Shetland Sheepdog, Belgians (Tervuren, Malinois,Lakenois, Groenendael).

Test for “a^t”

Vetgen is now offering a test for a mutation that is found in all tan point, phantom, tricolor, and "black/tan, chocolate/tan and liver/tan" dogs. This mutation, a^t, was identified and reported by researchers at the University of Saskatchewan.

In order to produce “a^t” pups, the pups need to inherit both an a^t and a k^y or k^br allele from both parents, but no KB . In many breeds where the occasional tan point dog is viewed as unwanted, the k test is still warranted since the majority of dogs have two copies of this a^t mutation, but do not express it because of the presence of an overriding K^B.

The “a^t” mutation is also found in recessive black dogs, but does not cause recessive black (a). In breeds that do not have recessive black (most breeds), this test alone will indicate the presence of “a^t”. In breeds where recessive black is present, “a^t” can be determined by using this test in conjunction with the recessive black test, or by our previous process of elimination approach of testing for A^y and recessive black.

It should also be noted that recessive black is present at a very low frequency in more breeds than we once thought (ie French Bulldogs, Poodles and Tibetan Mastiff).

Testing for this mutation along with A^y and recessive black (a) also allows for the identification of a^w alleles in those breeds where it is present.In breeds where only the A^y and a^t alleles are present, the A^y test can be used to see if the fawn/sable dog is A^y/A^y (homozygous) or only has one A^y (heterozygous). If it only has one, the other allele must be a^t (ie Afghans,Collies,Cardigan Welsh Corgi, Dachshund, Norwich Terrier, Staffordshire Terrier).

In breeds where only A^y, a and a^t alleles are present, both the A^y test and the "a" test need to be performed. Any alleles unaccounted for by these two tests will be a^t. For example, if a dog is A^y/A^y both alleles are accounted for. If a fawn/sable dog only has a single A^y, then the other allele must either be an "a" or an a^t and this can be determined by running the recessive black ("a") test or the a^t test (ie Shetland Sheepdog, Belgian Shepherd (Tervuren, Malinois, Lakenois, Groenendael).

D Locus

The D locus is the primary locus associated with diluted pigment, which results in coats that would otherwise be black or brown instead showing up as gray, or blue in the case of black, and pale brown or Isabella in the case of brown. The melanophilin gene has recently been shown to be responsible, but not all of the dilute causing mutations have been identified yet.

M Locus

The M locus is responsible for the merle and double merle color patterns seen in some breeds. The mutation which causes merle in all of its forms has been identified. VetGen cannot offer a test for merle because it is patented elsewhere.

Coat Length

While it is not a color trait, the length of a dog's coat is of interest to many. It has recently been demonstrated that in many breeds, the FGF5 gene is responsible for whether a dog has a long coat (rough or fluffy), or a short (smooth) coat. The test Vetgen offers detects the presence or absence of the recessive allele that results in long coats when present in two copies, and as such allows dogs with short coats that carry a hidden "long coat" allele to be detected. In addition to the original coat length mutation, research at VetGen has identified some new mutations present in northern breeds (Akita, Chinook, Siberian Husky) that are responsible for the "woolly" long coat. These new tests are offered exclusively through VetGen.

Furnishings

Furnishings refer to the longer facial hair around the eyebrows, moustache, and beard commonly seen in many breeds, including the wirehaired breeds. Presence of furnishings is dominant to the unfurnished version of the gene, which depending on breed may also be referred to as satin, or sleek. VetGen offers a test to see if a furnished dog carries the recessive unfurnished trait, which is considered unfavorable in some breeds.

Curly

The gene responsible for curly coat has also been identified. Most breeds are fixed for either curly or not-curly, but in breeds where there is variation, dogs may now be tested to see if they carry zero, one or two copies of the curly or non-curly versions of the KRT71 gene.

Good information.  About 40 years ago I took an advanced animal genetics class at university .. at that time the professors assured me they knew everything.  My sister is a genetic counselor and she assures me that in 2015 they ( geneticists and genetic researchers) still don't know everything and likely never will.  Remember that the term "incomplete penetrance" means we don't understand yet or simply we don't know.  Knowing what genes are involved does not mean they are the only genes involved and there are many multiple allele traits such as hip dysplasia which are not explained by our current genetic knowledge of the GSD or pretty much any breed of dog. Likely hip dysplasia is a combination of environment, maternal RNA and epigenetic controls, injuries and trauma ( part of environment ), and multiple allele gene expression.  Even some of the most successful genetic tests are only 70% predictive.  The test can say that you have or don't have the gene (in at least some of your body tissues .. see mosaic) but it is likely only 70% accurate in predicting the genetic expression of the condition, disease, or abnormality in the offspring of the individual.   The simpler the inheritance pattern the easier it is to predict but no test is 100% or even close in being able to predict  .. much better at telling you that you have the gene or not than whether having the gene predicts the expression of the gene and the disease or condition in the offspring.

The only valid point I heard in this discussion so far is the one about keeping the gene pool open by using reversed masked dogs. To that 

 

To me, these claims:

1. Reversed masked dogs have better qualities. NO PROOF

2. This specific dog has good qualities. Not convincing, there are as good if not better qualities in many dogs with better mask, better structure and better pigmentation.

3. Quality comes before beauty. No one asked you to use less quality, but use more appealing dog

4. Reversed mask is not same as maskless. Genetically it is maskless or less masked. But I have no proof, only my impression. Reversed mask is just a term some one used to describe such a pale light colored mask.

 

 

Seems to be some major lack of comprehension going on. 

Nowhere did anyone say a reverse mask or any other pattern or color of coat or eyes CAUSES a damn thing. We are simply saying in our experience (and in others' far more experienced and knowledgeable) that there have been too many CORRELATIONS to ignore in particular combinations of genes/breeding pairings. I have also noticed the lighter eye correlation Gustav speaks of. The breeding I'm deciding on now is this way and the crowd wants the dark eyed dog. The lighter eyed dog is equal or superior to that dog in nearly every aspect. Is it because his eyes are lighter? I highly doubt it, but why can't anyone process the possibility that the very genes that make him the superior dog are commonly bundled with the genes that gave him slightly lighter eyes? We just don't know! So why not look at every single detail when putting together a breeding? 

Does that mean if I see a reverse masked dog with lighter eyes it must be a superior dog? Of course not! But when breeding lines already known for working ability and trying to strengthen and focus on particular traits, it behooves one to heed such correlations as they see them occur, ie, if, in a particular pairing, the reverse masked dogs seem to be stronger than their dark sable littermates 75-85% of the time, that's a relationship worth making mental note of. When this occurs with enough regularity to be predictable, then when you want to select for the traits those dogs bring, if you have two equal dogs, one of each trait, it just makes sense to use the one most likely to pass on these traits.

I guess it's not enough science for vk4 or enough rationalization for Ibrahim, but when a guy eligible for AARP can look at a ped I'm thinking of and tell me I'm going to get rear dewclaws in 2-3 pups and that they'll likely also be the strongest pups, and be right...well...coincidence? Maybe. Possible. But awfully lucky guess. 

I will argue that Ibrahim is wrong about the mask. Maskless means without mask. These dogs have masks. The mask is the opposite color, hence the term "reverse." Maskless would mean no mask, like in the case of a pale dog with completely tan face. I don't see this as a matter of opinion at all, or even terminology. The mask pattern is reversed. These are not plain-faced dogs. 

Duke, should be working fools w/that linebreeding. 

If we agree that such "reversed masks" = lack of mask, then as per FCI standard, such a dog lacks in pigmentation

From FCI standard:

 Dogs with lack of mask, light to piercing eye colour, as well as with light to whitish markings on the chest and the insides, pale nails and red tip of tail are considered to be lacking in pigmentation