Another border collie color genetics question

[kimkathan]

I was wondering...

I know that a black and white dog can carry a recessive red gene, but if a dog is a black and white TRI, does this mean that they HAVE TO carry a recessive red gene? Just a mind query as to what the likely hood of breeding a black and white tri to a Red dog would be. The Tri comes from a B/W tri bitch and a B/W male, the red from a red bitch and a B/W male. Also, is it true that you need tri allels from both parent to have a tri?

[Sue R]

But aren't there also red and white tri's, just like you can have black and white tri's? Mind you, I did not do well in genetics in college...

[kimkathan]

Yes there are Red tri's, but if the male is not a red tri, but a true red....?

 

I guess what I'm wondering is are the tan markings on a try conclusive with a dog carrying a red gene.

[Sue R]

I don't have a clue!

[Journey]

No. A tri is a gene into itself, no bearing on the body color of the dog.

 

ETA - you could get all tri, no tri's or a split between them. It depends on whether or not the one carries the tri gene. Even still chances are if they are not tri pups they will carry the tri gene.

[Eileen Stein]

I was wondering...

I know that a black and white dog can carry a recessive red gene, but if a dog is a black and white TRI, does this mean that they HAVE TO carry a recessive red gene?

 

No. Assuming that you're referring to what working border collie people call red (brown nose), and not Australian red (black nose), red is expressed when the dog inherits two copies of the recessive b allele, and tri is expressed when the dog inherits two copies of a different, separate recessive allele in the agouti (A) series.

 

Just a mind query as to what the likely hood of breeding a black and white tri to a Red dog would be. The Tri comes from a B/W tri bitch and a B/W male, the red from a red bitch and a B/W male. Also, is it true that you need tri allels from both parent to have a tri?

 

The B&W tri dog has only tri alleles to contribute; the red dog may or may not have a tri allele to contribute, based on the info given here. The red dog has only red alleles to contribute; the B&W tri dog may or may not have a red allele to contribute, based on the info given here. So based on the info you have, you could get any of these: B&W, B&W tri, R&W, R&W tri. But all the pups will carry at least one tri allele and one red allele.

[Journey]

Let me try this again....

 

I was wondering...

I know that a black and white dog can carry a recessive red gene, but if a dog is a black and white TRI, does this mean that they HAVE TO carry a recessive red gene?

 

No. A tri has no bearing on body color.

 

The Tri comes from a B/W tri bitch and a B/W male, the red from a red bitch and a B/W male. Also, is it true that you need tri allels from both parent to have a tri?

 

The B/W male carried the tri gene, that's how the dog ended up a tri. The red bitch came as the B/W male carried the red gene. Yes, you need both genes from the parents to get a tri, but both parents don't necessarily have to express the tri gene.

[mjk05]

No, tri markings have nothing to do with red.

 

Both tri and red are recessive, so as previous posters have said you could end up with red, black tris, red tris and hypothetically also dilutes (if both parents were carriers) so lilacs, blue and tri variants of those. But most likely is that you'll get black and whites.

 

Eileen wrote:

Assuming that you're referring to what working border collie people call red (brown nose), and not Australian red (black nose)

That's not the ideal way to differentiate, because ee red (aka Australian red, cream, yellow) can and does also occur in dogs that are genetically chocolate red (bb), which means they'll have brown noses too.

[juliepoudrier]

The B&W tri dog has only tri alleles to contribute;

I'm not sure this is entirely accurate. At least in shelties (and I've always understood that sheltie coat color genetics are probably the same as those for border collies), tri, sable, and B&W all occur at the same locus (A). Sable is a^y, tri is a^t, and B&W is a. From what I've read, sable is dominant to tri which is in turn dominant to B&W. So it's possible to have a tri that is a^t/a, which would appear tri, but which could pass on the a to its offspring to produce only B&W. I know this doesn't take into account the "dominant black" genetics, but it seems there is disagreement on where dominant black actually belongs. Of course if B&W in border collies is controlled by a dominant black (like A^s), then I don't think tri would be expressed anyway. But I'm far from being a genetics expert.

 

And my sources also say that MJK05 is correct: ee (Aussie red, clear red, or yellow) can occur with bb (brown or liver), so it's not always possible to predict the genetic color of a dog based on nose color.

 

J.

[mjk05]

At least in shelties (and I've always understood that sheltie coat color genetics are probably the same as those for border collies),

I think that shelties and collies (rough/smooth Lassie collies) actually have a different inheritance of black- they have recessive black (on the A locus) too. It's my understanding that border collies (and kelpies) don't seem to have recessive black. Might be wrong though.

[juliepoudrier]

I don't know either, and of course the best sources I have are all based on sheltie color genetics. At least one of those sites questions placing dominant black in the A series at all! I guess that explains the confusion about the dominance of tri, since I had always heard tri was dominant, but apparently that's not always the case. Although since Lassie collies came from the same progenitor stock as border collies, it would make sense if their color genetics were similar (infusion of Russian wolfhound blood in the Lassie collie notwithstanding...).

 

J.

[Journey]

I too have always heard that Tri was dominant. There is some new research being done on the Black gene. From the little I have seen it is questionable as to whether or not many of the B/W dogs are truly black and not Sables.

[mjk05]

Quick goole re recessive black- this one says:

Most solid black dogs are solid black because they have the dominant black gene, but there is another type of black - recessive black. Recessive black is very rare and only occurs in a handful of breeds, including the German Shepherd Dog, Shetland Sheepdog, Schipperke and Puli. Some breeds, such as the Belgian Shepherd Dog, are thought to carry both recessive and dominant black.

 

Would be interested to hear if anyone has any other info.

[juliepoudrier]

From this Sheltie color genetics site (the site I [used to] use as my main source of information) comes this:

 

A, the agouti series. The standard assumption, based on Little's research, is that this series contains four alleles (different forms of the gene). A fifth allele may exist in Shetland Sheepdogs, and a sixth in certain "saddle-tan" breeds.

 

A^s produces black without any tan on the dog. White markings are due to a different gene, and there are other genes that can modify the black to liver (chocolate Lab) or blue dilute (blue Great Dane.) If A^s is present, in most cases the dog will be able to produce only eumelanin pigment (but see the E series). Note that the agouti series is known in a number of mammals, and dominant black is almost always found in a different series, so there is a strong possibility that dominant black is not really in the agouti series.

 

a^y in the absense of A^s produces a dog which is predominantly tan (phaeomelanin) sometimes with black tipped hairs or interspersed black hairs. The usual term for this color is "sable." In examining dogs from a^y breeds, I have generally found that even if there is no other black on the coat, the whiskers (the course, stiff vibrissae, not the "beard" seen with some terrier coats) are black if they originate in a pigmented area. Examples of a^y dogs include Collies, fawn Boxers and Great Danes, and some reds (Basenji red is thought to be ay, for instance.) a^y is recessive to A^s, but incompletely dominant to a^t. That is, an a^ya^t dog is on average darker (more black hairs) than an ayay dog, but the difference is generally within the range of color for a^ya^y within the breed.

 

a^t, present in double dose, produces a dog which is predominantly black, with tan markings on the muzzle, over the eyes, on the chest, legs, and under the tail. A Dobermann or Rottweiler is a good example of the classic black and tan pattern. The Bernese Mountain Dog shows the effect of black and tan combined with white markings, often called tricolor.

 

a^w is the fourth allele considered by Little. This is the wild "wolf-color" seen in Norwegian Elkhounds and possibly in some salt-and pepper breeds. It differs from sable in two ways. First, the tan is replaced by a pale cream to pale gray color. Second, the hairs are normally banded - not just the scattering of black-tipped hairs sometimes seen in a sable, but several bands of alternating light and black pigment along the length of the hair. Little was unable to determine the dominance relationship of this gene, or even to say with certainty that the banding and the reduction of tan pigment were due to the same gene.

 

Although Little did not make any distinction between the Dobermann black and tan and the "saddle tan" seen in many terrier breeds (black "saddle" but extensive tan on legs and head), it seems likely that a fifth gene exists in the a series. For the moment I'll call it "saddle tan," a^sa. It seems recessive to ay sable, but other dominance relationships in the series need more investigation.

 

Finally, at least two breeds (Shetland Sheepdog and German Shepherd) have a fully recessive black. Since black is the bottom recessive of the A series in many other mammals, it seems logical to assign this color to recessive black, a, and state that recessive black is caused by aa at the agouti locus. There is an alternative theory in Shelties which suggests the existence of a recessive gene that removes tan points from a genetic black and tan or a dominant, widespread gene that forms tan points on all colors but dominant black.

[emphasis added]

Little's assignment of dominant black in dogs to the A locus (A^s) is totally against experience with this locus in other species, where more yellow is generally dominant to more black. There may be a third locus controlling dominant black, in which case Ay would be the top dominant in the A series.

 

This site has more updated information from DNA studies. It puts black on a K locus, and has this to say:

 

The K Locus

 

Little postulated another allele A^S causes solid or self-colored dogs. Such dogs could be the red Chow or some red Basenji. Later authors, such as Willis (1989) and Sponenberg (2001) have for some reason begun to call this A^S allele "dominant black". Kerns et al. (2003, 2005) have recently shown that this "dominant black" is not caused by an agouti allele using DNA studies. "Dominant black" by their definition is a genotype that is epistatic to fawn, sable, etc. agouti phenotypes which occurs at another locus, K (for blacK). Several dog breeders have suspected this for some time. The K locus is located on an entirely different chromosome than the agouti locus. Dr. Sophile Candille has studied the alleles in this series, and has been joined by Dr. Christopher Kaelin in this effort. The Stanford group has decided to refer to the three alleles as K^B, k^br, and k^y as of April, 2007.

 

And this:

Dominant Black

 

K^B is a critical allele in the formation of black pigment in at least 50 breeds such as the Great Dane, Greyhound, Whippet, etc. but in many breeds it does not vary. In some hunting breeds, such as the Labrador Retriever, all dogs are homozygous for K^B. In such breeds, the E locus alone then determines whether the dog is black or red. In other hunting breeds such as the German Shorthaired Pointer, the German Wirehaired Pointer, etc. the K^B/K^B genotype is fixed and the B locus determines whether they are black or brown. Although Little originally thought A meant solid black, and we suggest the K^B allele is actually the allele causing this type of black, "solid" does not mean that no white markings occur.

 

In order to find this "new" gene K, it was necessary to recruit a large number of dogs. Great Danes, Boxers and Afghans were especially useful but one Akita and one Greyhound were also extremely important in identifying the mutation..

 

The gene is a beta-defensin. This family of genes has been known to play an important role in immunity in humans, mice and other animals previously. This is the first time that a defensin gene has been shown to affect pigmentation though.

 

The discovery of this gene will also DNA testing to determine which dogs are homozygous for black, and which are heterozygous, in breeds that have black and fawn or black-and-tan varieties, such as Pug, Miniature Schnauzer, Briard, Japanese Chin, Italian Greyhound, etc.. This test is now offered by HealthGene..

 

Knowing if your black, brown or blue dog is homozygous black may be helpful to breeders for other reasons too. Although all Weimaraners are meant to be K^B/K^B, occasionally a litter contains a couple pups that have pale tan leg markings. This immediately means that both solid colored parents must be K^B/k^y, but what of the other pups in the litter. They could be tested to determine which are K^B/K^B (Noa Safra, Pers. Comm.).

 

A Great Dane breeder who is looking for the right stud dog for her Harlequin bitch and prefers a mate that is homozygous black would find this test helpful. Conversely an Afghan breeder who may be hoping the beautiful black stud dog being considered is not homozygous black, since a variety of coat color in the litter improves pup choice and sales.

 

All of the following dog breeds are black, brown or grey because of K^B and could be tested for homozygosity. Both the brindle mutation and the k^y allele are recessive to K^B. Distinguishing these two recessive alleles with a "simple" DNA test is not yet possible since the brindle mutation is a complex mutation.

 

Afghan

Akita

Australian Shepherd

Basenji

Bearded Collie

Border Collie [emphasis added]

Borzoi

Bouvier

Briard

Brittany Spaniel (French)

Chesapeake Bay Retriever

Chihuahua

Chow

Cocker Spaniel

Curly Coated Retriever

Dalmatian

English Pointer

English Setter

English Springer Spaniel

Field Spaniel

Flat Coated Retriever

French Bulldog

German Shorthair

German Wirehair

Great Dane

Greyhound

Griffon

Italian Greyhound

Jack Russell Terrier

Japanese Chin

Kerry Blue Terrier

Labrador Retriever

Large Munsterlander

Miniature Schnauzer

Newfoundland

Pomeranian

Portuguese Water Dog

Pug

Scottish Terrier

Shar-Pei

Shih Tzu

Standard Poodle

Tibetan Terrier

Weimaraner

Papillon

Whippet

 

According to the site above, brindle is also part of the K series (K^br), and another interesting bit of information:

ky/ky Phenotypes

 

Dogs which have two recessive alleles (k^y/k^y) can express a variety of phenotypes. All black-and-tan dogs or dogs with tan points are k^y/k^y. All fawn or sable dogs are k^y/k^y, whether they have a melanistic mask or not. Red dogs that have an e/e genotype however, could be any genotype at the K locus.

 

The Stanford group chose to name this allele k^y since it allows yellow or phaeomelanin pigment to show. Where it shows depends on the alleles at the agouti locus.

 

I guess I need to update my sources from my old sheltie color genetics standby! The second site I quote from seems to have the most up-to-date information.

 

J.

[Eileen Stein]

I'm not sure this is entirely accurate. At least in shelties (and I've always understood that sheltie coat color genetics are probably the same as those for border collies), tri, sable, and B&W all occur at the same locus (A). Sable is a^y, tri is a^t, and B&W is a. From what I've read, sable is dominant to tri which is in turn dominant to B&W. So it's possible to have a tri that is a^t/a, which would appear tri, but which could pass on the a to its offspring to produce only B&W.

 

To the best of my knowledge, border collies do not have recessive black (a). This belief has been bolstered by my real life experience -- I have never known a mating between two tris to produce non-tri pups. Has anyone else ever seen non-tri pups born to a mating between a tri sire and a tri dam in border collies?

 

Eileen wrote:

Assuming that you're referring to what working border collie people call red (brown nose), and not Australian red (black nose)

That's not the ideal way to differentiate, because ee red (aka Australian red, cream, yellow) can and does also occur in dogs that are genetically chocolate red (bb), which means they'll have brown noses too.

 

I'm sure you're right about this. So far as I know, ee red is totally unknown among working border collies in the US and UK, and I have never paid as much attention to it as I should. All bb's have brown noses, and all the ee's I've ever seen (Kennel Club dogs) have had black noses, but it stands to reason there are bb ee border collies who have brown noses.

 

Kim, I bet you're sorry you ever asked this question.

[Journey]

To the best of my knowledge, border collies do not have recessive black (a). This belief has been bolstered by my real life experience -- I have never known a mating between two tris to produce non-tri pups. Has anyone else ever seen non-tri pups born to a mating between a tri sire and a tri dam in border collies?

 

 

Correction to my earlier comments - the Tri gene is a recessive gene, went back and re-read my book, sorry! Eileen yes, I have seen pups from 2 distinct Tri's that produced black bi's - this is why the questions started arising about the dominant black and whether or not we have true blacks or are they black banded sables, with the majority of what we see in the body being black and very little of the hair at the base being yellow, distinguished under microscopic examination. There is questions that true black are very old lines or inbred for color. The color appears to be coming from the Agouti gene. And is there a True Black Tri in this breed? As in the true Tri in the Doberman and Rotti? Very distinct marks, not "smudged" through the body, masks and other areas..

[mjk05]

So far as I know, ee red is totally unknown among working border collies in the US and UK, and I have never paid as much attention to it as I should.

I don't think it's totally unknown in the UK, just very very rare. I've heard of 2 dogs from pure UK bloodlines that were cream, both obedience dogs but going back to ISDS, and no Australian/NZ blood. I think it's probably just a very rare thing that was consolidated in the initial dogs bred here (kelpies and collies).

[juliepoudrier]

To the best of my knowledge, border collies do not have recessive black (a).

Yep, that's why I quoted the second source above (Stanford study), which puts border collies as dominant black on a K locus and noted that it was more recent information and probably a more accurate description to use when discussing border collie color genetics (vs. Shelties).

 

J.

[Liz P]

To the best of my knowledge, border collies do not have recessive black (a). This belief has been bolstered by my real life experience -- I have never known a mating between two tris to produce non-tri pups. Has anyone else ever seen non-tri pups born to a mating between a tri sire and a tri dam in border collies?

 

Only when the tri was in fact a sable tri and not a tan point tri.

[ejano]

I remember a little chart from 8th science class that expressed Gregor Mendal's experiments with plant genetics....the teacher had us work it out with the various coats of horses (she was the leader of the horse club as well).

 

A more complicated form of that chart is listed at http://anthro.palomar.edu/mendel/mendel_1.htm

 

You might be able to plug in some of the variables given here and in the discussion of "Any red dogs out there?" and get some kind of results.

 

My pup Robin is a dark red (chocolate?) tri- color with a lovely brown nose. He was one of three dark reds out of six pups and the only tri color. His parents were both black and white but both were known to carry the red recessive gene. It was highly probable that the litter would have some red pups because a previous litter from the same pairing had produced dark red dogs, at least one of them tri-colored, though not to the extent that Robin is. He has gold eyebrows, gold around his muzzle and ears, and an unfortunate gold tuft around his tail. Kinda silly looking . All the red pups, including Robin, have the standard tuxedo looks, only red and white...oh, and very few brown freckles.

 

 

Where do freckles and eyebrows come from? One folktale I've heard about eyebrows is that the herding/gaurd dog would appear to have an open, watchful pair of eyes if the dog happened to be dozing.

 

Thank you for explaining why his nose is brown. I wondered about that.

 

Liz

[kimkathan]

First off Eileen, no I'm not sorry I asked the question. Something about genetics brings me to awe as to how complex an organism of any kind is. Thanks for all the input from all. I think that I get it now, that the red gene has nothing to do with the alele for the tri patterning. I need to go back several more generations to see if I can back track more on the male and see if there is any tri patterning, not that this is going to change anything.

 

Thanks to all

[Little Bo Boop]

I have a question, I am a total genetics dunce, so if its a stupid question, sorry ;-) The first reg. Border Collie I ever owned, was traditional blk/white, yet he came out of two red/wht. dogs. there were 8 in the litter, and all were blk/wht, they didn't throw a single red dog. Is that a normal occurance? or would that be considered a tad odd?

[juliepoudrier]

My first thought would be to wonder if the sire and dam were truly who the breeders said/thought they were. I guess there could be a way for the B (which is where recessive red comes from) and the K gene (which is where dominant black comes from) to interact in such a way for red dogs to produce black puppies. I wonder if the woman doing the DNA research I quoted above could answer that question? Her contact is

 

Sheila M. Schmutz, Ph.D., Professor

Department of Animal and Poultry Science

College of Agriculture

University of Saskatchewan

Saskatoon, Canada S7N 5A8

 

phone: (306)966-4153 fax: (306)966-4151

e-mail schmutz@sask.usask.ca

 

I'd be interested to know the answer!

 

J.

[ejano]

I have a question, I am a total genetics dunce, so if its a stupid question, sorry ;-) The first reg. Border Collie I ever owned, was traditional blk/white, yet he came out of two red/wht. dogs. there were 8 in the litter, and all were blk/wht, they didn't throw a single red dog. Is that a normal occurance? or would that be considered a tad odd?

 

 

The red is recessive....two BW dogs can have red pups if they both have the recessive gene, in fact I think it takes the gene on both sides to have a red dog. For example, RObin was one of three reds in a litter of six pups. Both parents were black and white and both were known to carry the red recessive gene.

 

Liz

[juliepoudrier]

Liz,

Betty's point is that if red is recessive, and it is, then if both parents are red, they have only a b to contribute to the puppies at the brown locus, and therefore all puppies should also then be bb, that is, red/brown. Because red is recessive, a litter like Robin's from B&W parents can have red pups, since the parents could carry the b gene without actually expressing it, that is, they could be Bb (but both parents would have to be heterozygous, that is Bb, at the B locus before red could be expressed phenotypically in any pups). What Betty is asking is how is it possible for two red parents, who by definition would be bb, to produce B&W pups, who by definition would have to have at least one B gene at that same locus, since neither red parent would be able to contribute the B needed to produce black. The only answer I can think of is if there is another gene at a different locus or chromosome that could override the lack of melanin production as coded by bb (which is what allows the red eumalanin to show through) to allow melanin to be produced to produce a black dog. I think perhaps the DNA research done by Dr. Schmutz et al. (since they have determined that there is a separate dominant black locus in border collies, labeled K) could possibly explain such a phenomenon, but don't know enough about the genetics to say for sure.

 

J.