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Pamela K. House - AKA Prism

Pamela K. House - AKA Prism
June 11, 1950 - June 7, 2013

Pam was an avid equine color genetics expert and a member of the American Quarter Horse Association. She answered equine color genetics questions as "Prism" with The Horse Gazette and she was an instructor of "Color Coat Genetics" for Horse Courses Online. Pam studied coat color genetics for more than 20 years in an effort to gain registration for Double Dilutes.


Dear Prism,
What color baby will you get if you breed a blue roan stud To a tobiano bay and white mare? - Wade White, Weatherford, TX.

Hi Wade,
Let's address the easiest part of your question first. If your mare is homozygous (2 copies of the gene) for tobiano the foal will be a Tobiano. If she is heterozygous (1 copy of the gene) for Tobiano there will be a 50% chance the foal will be a Tobiano. Now for the more difficult part of your question - we know from the colors that both parents are black-based but what we don't know is whether or not one of them is homozygous for the black gene. I am going to make a couple of assumptions here; 1) both parents are heterozygous for black (carry 1 black and 1 red gene) and 2) the mare is heterozygous for the Agouti gene (Agouti limits the black coloration to the point; mane/tail, lower legs). So your possible foal colors could be - Sorrel, Red Roan, Black, Blue Roan, Bay or Bay Roan. - Prism


Dear Prism,
Hello I have a black roan stud. He was dark as colt but is lighter grey with dark legs main and tail now. I want to breed him to a red and white paint. What color possibility for colt? Thanks so much - Chad, Huntington, WV.

Hi Chad,
Your question is very similar to Wades question and my answer will be similar. The exception is that all red horses are homozygous for the recessive Extension gene so we know that the foal will inherit a red gene from the dam. So your foal colors could be; Sorrel, Red Roan, Black, Blue Roan, Bay (cause red horses can carry Agouti, we just can't see it) or Bay Roan. There will be a 50% chance the foal will be paint. - Prism


Dear Prism,
I would like to know what color foal I would be looking at if I bred a black and white mare to a buckskin stud? Chandler, Weatherford, TX.

Dear Chandler,
We would need to know the black status of both horses (1 or 2 copies of the black gene) and we know buckskins are bay horses with one copy of the dilute gene. We also need to know the Agouti status on the buckskin (1 or 2 copies of Agouti). Making the assumption that both horses are heterozygous (1 copy) for black and the buckskin is heterozygous for Agouti your foal colors could be Sorrel, Palomino, Bay, Buckskin, Black or Smokey black. Of course, there is a 50% chance the foal would have the paint genetics. - Prism


Dear Prism,
I'm looking at a few different studs and cannot find the right combination in my color genetics book. Mare is gray - what color would I get if I crossed her w/: red roan? dun? buckskin? Assuming if I crossed on another gray - I'd get a gray. Any help you can provide would be great. Thanks! Merideth, submitted via HorseGazette.com

Dear Merideth, First we need to remember that Gray is the 'ultimate modifier' and not a "color" like Sorrel or Bay in that it turns all other colors gray. So before I can answer your question I need to know what color the mare was born. All gray horses are born another color and they turn gray. So, not knowing what color your mare was born, I cannot answer your question. If you can't find out the birth color I strongly recommend you have her tested to find out what factors you are dealing with. I also recommend UC-Davis (http://www.vgl.ucdavis.edu/services/horse.php) for the testing. UC-Davis has been in the forefront of equine color testing for years and developed many of the tests being offered. In the case of your mare I would test her for Red-factor and Agouti as the basic tests. - Prism


Dear Prism,
I have bred my buckskin mare to a palomino stallion. The pali comes from Sorrel and pali and the buckskin comes from bay and pali. What do you think my foal will be? - Andrea, submitted via HorseGazette.com

Dear Andrea,
Let's take the colors of your mare and the stallion down to the basics. Buckskin is Bay plus one dilute gene and Palomino is sorrel plus one dilute gene. So let's talk Bay (Black plus Agouti) crossed on Sorrel. The color possibilities would be Sorrel, Black or Bay. If you add one Dilute gene you could get "Smokey Black", Buckskin or Palomino and if the foal inherits a Dilute gene from both parents you could get Cremello, Perlino or even Smokey Cream. - Prism


Dear Prism,
I purchased a 1/2 paso fino and 1/2 mountain horse chestnut mare. Just found out she is bred to Docs Rumba King - palomino AQHA. Wondering what color we might get? The sire's pedigree shows palomino, sorrel, chestnut, black, roan, buckskin and grulla. - Pam Miller, via HorseGazette.com

Dear Pam,
Given the mare is chestnut (homozygous for recessive red gene) and bred to a Palomino (homozygous for recessive red gene plus one (1) copy of the dilute gene) your offspring will be either Chestnut or Palomino. Neither parent carries the black. Roan or Dun genes. - Prism


Dear Prism,
Just had what seems to be a cremello colt with a red man and tail. Ever heard of this and what could it eventually turn out? Thank You. - Robert, Waynesboro, TN

Dear Robert,
Need a little more info in order to answer your question. What color are the parents and do you have a pic of the foal? Keep in mind in order to get a "cremello" foal both parents have to carry one Dilute gene, making them palomino, buckskin or smokey black, and even then you would only have a 25% chance of a cremello foal. If the foals eyes are brown - you don't have a Cremello. Characteristics of a Cremello are: Blue eyes, cream colored coat with a pumpkin hued skin. White markings are visible on cremellos. If none of the above apply to your foal then chances are you have a possible palomino (I've see newborn palominos which range from a Terra-cotta orange to almost white) or perhaps a buckskin. Without a picture to go on I'm just guessing at all of the above. - Prism


Dear Prism,
I have a buckskin appaloosa mare who was bred in 08 to a buckskin appaloosa stallion, the result was a perlino few spot appaloosa colt. He was tested to have a double Cr Cr gene. From what I have been informed of is that no matter what I breed him to i will always get a buckskin. I was also wondering what are the odds of getting another perlino foal if I bred her back to the same Stallion? Thanks, Kim Menser, San Antonio, TX

Dear Kim,
Well Kim, Buckskins carry 1 dilute gene each making them "cCr" and they carry at least one Agouti gene (A - limits the black color to the points making a bay out of a black horse). Remember, buckskins are bay with at least one copy of the Agouti. The chances of the foal inheriting two genes (needed for a Perlino) would be approximately 50% The foal will inherit either the following; "c" the foal will be a Bay (25%), "cCR" and the foal will be a buckskin (cCr) or "CrCr" and the foal will be a Perlino. The other question to ask would be "Is one parent homozygous for the black gene?" If yes, then the foal will always be black-based. If both parents are heterozygous for black (one black gene and one red gene) then you could get a Sorrel or Palomino foal. - Prism


Dear Prism,
I have a sorrel paint stud that I'm breeding to a palomino dun mare. I was just wondering what color the baby would be? Thanks Caitlyn, submitted via HorseGazette.com

Dear Caitlyn,
Well we know the baby will be red-based. Both the Sorrel and the Palomino are homozygous for red (ee). The only modifiers available in the mix are the Dun genetics and the Dilute/Cream genetics - both of which have to be passed to the foal by the mare. So your foal could be Sorrel, Red Dun, Palomino or Palomino (Dunalino). - Prism


Dear Prism,
I have a gray mare that I am putting to a pinto stallion what colors are possible for the mating? - Elizabeth House, submitted via HorseGazette.com

Dear Elizabeth,
That will be difficult to tell due to the fact you didn't state what color the mare was born nor the color of the stallion. The mare is gray and gray is a modifier and not a color. You did say that the stallion was a pinto so you run an approximately 50% chance of the foal being a pinto. (If the stallion is homozygous for pinto genetics then the foal will be a pinto) - Prism


Dear Prism,
I have a sorrel mare bred to a dun roan what do you think we'll get? - John, submitted via HorseGazette.com

Dear John,
The foal could be almost any base color - Sorrel, Black or bay. Whether or not the foal inherits the Roan or Dun genetics is totally in the stallion's "hooves". If he passes the Roan gene you could have a Red Roan, Bay Roan or Blue Roan. If he passes the Dun gene then you could have Red Dun, Classic Dun or even possibly a Grullo. It would also be possible for the foal to inherit both the Dun and Roan genes. - Prism


Dear Prism,
Hi, I was wondering what I might get for color out of my bay paint breeding stock mare she has 4 white sox up past her knees white face both her parents are overo one black & white one sorrel & white my stud is a red roan strong with roan with a black and kind of silvery gray mane and tail 2sox and a blaze. I believe both parents to the stud were roan as well was wondering if you could tell me what color I might expect. Thank you for your time. - Jody, submitted via HorseGazette.com

Dear Jody,
Umm, heterozygous Bay Solid Paint, out of a black/white x sorrel/white overo parents bred to a Red Roan with black mane/tail. First, the stallion is actually a Bay Roan (Note: Until just a few years ago AQHA would not reg. a Bay Roan as a Bay and the only choices were a Red Roan or a Blue roan. That has since been corrected). The fact your mare has white socks past her knees and a white face tells me she probably (like 99%) carries the Overo genetics so she could throw a loud paint colt - just a case of "baby roulette". As far as color? Bay is a black horse with Agouti and not knowing the Agouti status of both parents I will make an assumption that each carries one copy. You didn't mention the black status of the stallion so again I'm going to assume he carries one of each; black and red. Your foal colors could be Sorrel, Black, and Bay with a 50% chance of being Overo paint and a 50% chance of the foal being a roan (giving you a Red Roan, Bay Roan or Blue Roan) - Prism


Dear Prism,
I have a dark bay or (brown as it says on her papers) QH mare. If I breed her to a cremello stallion what possible color foal could she have? I know once when her previous owners had her they bred her to a palomino stallion and she had a beautiful sorrel with silver (not flaxen) mane and tail, blaze face and four white stockings. Thanks, Mike.

Mike,
Knowing that your mare produced a sorrel lets us know she is hetrozygous for black (carries 1 black gene (she's a dark bay/brown) and 1 red gene. We know that a Cremello is homozygous for the red gene as Cremello is a sorrel with 2 dilute genes. We also know the Cremello is homozygous for the Dilute/Cream gene. So breeding to a Cremello guarantees one of three colors; Smokey Black (a black that carries 1 dilute gene), a Palomino (red base/sorrel with 1 dilute gene) or a Buckskin (Bay with 1 dilute gene. Only three colors possible when breeding to a Double-dilute. - Prism


Dear Prism,
I have a sorrel mare with a cream gene. If I breed her to a grullo, what are the color combinations I could get? Thanks, John B

John,
I'm a little confused - are you sure the mare carries a cream gene? If she did she would be a Palomino and not a sorrel. Grullo is a Black with the Dun genetics. To answer your question, I'm going with the phenotype you gave me; Sorrel. Breeding a Sorrel to a Grullo could result in the following foal colors; Sorrel, Red Dun, Bay, Classic Dun, Black or Grullo. - Prism


Dear Prism,
I have a dark bay or (brown as it says on her papers) QH mare. If I breed her to a cremello stallion what possible color foal could she have? I know once when her previous owners had her they bred her to a palomino stallion and she had a beautiful sorrel with silver (not flaxen) mane and tail, blaze face and four white stockings. Thanks, Mike.

Mike,
Knowing that your mare produced a sorrel lets us know she is hetrozygous for black (carries 1 black gene (she's a dark bay/brown) and 1 red gene. We know that a Cremello is homozygous for the red gene as Cremello is a sorrel with 2 dilute genes. We also know the Cremello is homozygous for the Dilute/Cream gene. So breeding to a Cremello guarantees one of three colors; Smokey Black (a black that carries 1 dilute gene), a Palomino (red base/sorrel with 1 dilute gene) or a Buckskin (Bay with 1 dilute gene. Only three colors possible when breeding to a Double-dilute. - Prism


Dear Prism,
I have a sorrel mare with a cream gene. If I breed her to a grullo, what are the color combinations I could get? Thanks, John B

John,
I'm a little confused - are you sure the mare carries a cream gene? If she did she would be a Palomino and not a sorrel. Grullo is a Black with the Dun genetics. To answer your question, I'm going with the phenotype you gave me; Sorrel. Breeding a Sorrel to a Grullo could result in the following foal colors; Sorrel, Red Dun, Bay, Classic Dun, Black or Grullo. - Prism


Dear Prism,
If I have a buckskin mare and want to breed her what color stud do I breed to get a buckskin foal. Susan - submitted via HorseGazette.com

Dear Susan,
Let's define "Buckskin" first. Buckskin is a bay horse with one copy of the Dilute/Cream gene. And a bay horse is a black horse with Agouti (limits the black color to the mane/tail/legs). Being buckskin we know your mare is black-based, carries at least one copy of the Agouti gene and carries one copy of the Dilute/Cream gene. We don't know the status of her Black and Agouti genes (one copy of each or two copies of them). Since we don't know her Black or Agouti status you could get the following if you breed her to a Bay stallion - Sorrel, Palomino, Black, Smokey Black (a black that carries the Dilute gene), Bay or Buckskin. There are a whole lot of unknowns in your question. Not knowing her status, I'd breed her to a bay stallion and hope she passes the dilute gene to a bay foal. If you breed her to buckskin you could get the approximate following percentages; 25% Bay, 50% Buckskin and 25% Perlino. - Prism


Dear Prism,
We are going to breed our chestnut w/flaxen mane and tail to a gray stallion. What will the offspring color be? Thank you! Briana, submitted via HorseGazette.com

Dear Briana,
That will depend on the stallions "Birth" or "Base" color. All gray horses are born a different color and turn gray with age and right now we don't know what the stallion brings to the breeding pool. All Chestnut/Sorrel horses are homozygous for the red gene and will always pass a red gene to foals. So any color besides "Red" will be up to the stallion. If he was born Bay or Black then you could get almost any color for the foal. If he was born Chestnut or Sorrel then the only color you will get would be "Red". The only firm, given fact in breeding horses is "If you breed a "red" horse to a "red" horse you will get a "red" horse." - Prism


Dear Prism,
I have a sorrel with flaxen mane and tail. What should I breed to, to give me the greatest chance in getting a buckskin? Melissa - submitted via HorseGazette.com

Dear Melissa,
Since your mare is a Chestnut we know she is homozygous for the Red gene. Since Buckskin is a Bay (black with Agouti) horse which carries one dilute gene. For your mare to have a buckskin foal you would need to find a stallion which is homozygous for black, homozygous for Agouti and homozygous for the Dilute/Cream gene (a Perlino). A guaranteed buckskin foal would be achieved by breeding your mare to a Perlino (Bay with 2 dilute genes) which is homozygous for black and homozygous for Agouti. The stallion will pass the black gene, the Agouti gene and one dilute gene to the foal resulting in a Buckskin foal. - Prism


Dear Prism,
If I have a buckskin mare and want to breed her what color stud do I breed to get a buckskin foal. Susan - submitted via HorseGazette.com

Dear Susan,
Let's define "Buckskin" first. Buckskin is a bay horse with one copy of the Dilute/Cream gene. And a bay horse is a black horse with Agouti (limits the black color to the mane/tail/legs). Being buckskin we know your mare is black-based, carries at least one copy of the Agouti gene and carries one copy of the Dilute/Cream gene. We don't know the status of her Black and Agouti genes (one copy of each or two copies of them). Since we don't know her Black or Agouti status you could get the following if you breed her to a Bay stallion - Sorrel, Palomino, Black, Smokey Black (a black that carries the Dilute gene), Bay or Buckskin. There are a whole lot of unknowns in your question. Not knowing her status, I'd breed her to a bay stallion and hope she passes the dilute gene to a bay foal. If you breed her to buckskin you could get the approximate following percentages; 25% Bay, 50% Buckskin and 25% Perlino. - Prism


Dear Prism,
We are going to breed our chestnut w/flaxen mane and tail to a gray stallion. What will the offspring color be? Thank you! Briana, submitted via HorseGazette.com

Dear Briana,
That will depend on the stallions "Birth" or "Base" color. All gray horses are born a different color and turn gray with age and right now we don't know what the stallion brings to the breeding pool. All Chestnut/Sorrel horses are homozygous for the red gene and will always pass a red gene to foals. So any color besides "Red" will be up to the stallion. If he was born Bay or Black then you could get almost any color for the foal. If he was born Chestnut or Sorrel then the only color you will get would be "Red". The only firm, given fact in breeding horses is "If you breed a "red" horse to a "red" horse you will get a "red" horse." - Prism


Dear Prism,
I have a sorrel with flaxen mane and tail. What should I breed to, to give me the greatest chance in getting a buckskin? Melissa - submitted via HorseGazette.com

Dear Melissa,
Since your mare is a Chestnut we know she is homozygous for the Red gene. Since Buckskin is a Bay (black with Agouti) horse which carries one dilute gene. For your mare to have a buckskin foal you would need to find a stallion which is homozygous for black, homozygous for Agouti and homozygous for the Dilute/Cream gene (a Perlino). A guaranteed buckskin foal would be achieved by breeding your mare to a Perlino (Bay with 2 dilute genes) which is homozygous for black and homozygous for Agouti. The stallion will pass the black gene, the Agouti gene and one dilute gene to the foal resulting in a Buckskin foal. - Prism


Dear Prism,
Hello. I have an AQHA filly that was born red dun with all of the dun factor characteristics (red leg barring, dorsal stripe, red mane and tail). Now, as she is shedding her baby fuzz, she is black underneath. She has three white stockings, and so far I cannot see any black coming through near her coronet band on her solid colored leg. However, every place else on her body where there is a nick or scrape, she looks very black. Where she is shedding out around her eyes and muzzle, she is almost black. The sire was a dun with black points, and the mother was a brown/black out of a black sire and sorrel mare. Any ideas? Thanks for your insight. – Submitted by Melissa K. Miller via HorseGazette.com

Dear Melissa,
Congratulations! You have a “Surprise Package”. One of the reasons I love foals so much as one rarely knows what they’re getting until the yearling coat shed off. Since both parents are black based they obviously carry a red-gene each (the filly was born Red Dun). Without pictures I really can’t take a learned guess but I’m going to say you’ll end up with a shade of red, won’t comment on the “Dun Factors” as many foals are born with what looks like Dun factors but are in fact Counter shading. I will say if she was going to be black based, the solid leg would be showing black color. - Prism


Dear Prism,
What colour stallion should I breed to a black mare to get a dun or grullo foal? I think that the mare may be heterozygous for black as her body fades to dark dun in summer (including dark golden flanks, and she has red lights in her mane and tail, although her points remain black. Also is it true that the agouti gene is dominant, so if a horse has received it from only one parent, it will affect the colour, but it will not necessarily be passed on to the offspring? Submitted by Tracy via HorseGazette.com

Dear Tracy,
You would need to breed to a Dun stallion to introduce the Dun genetics/markings into the mix. You would still have a 50% chance of the resulting foal being a dun. As far as the black status of the mare – easy way to know is to have her tested. Pull mane hairs and send to a lab for the “Red Factor Test”. The test will let you know if she carries the red gene or not As far as the Agouti? Agouti only affects the black color so many red horses carry agouti but you would never know without testing. And yes, Agouti is a dominant gene and just one copy will give you a Bay horse instead of a Black horse. As with all genetics – when one copy of a gene is present there will be a 50% chance of that parent passing along to the offspring. - Prism


Dear Prism,
I have a filly whose dam is palomino and sire is black/bay. The filly is a very light sorrel with lighter legs belly and chest. I have seen pictures of foals this color that are advertised as palomino. How do I know if my filly will turn palomino or stay sorrel? Submitted by Bridget via HorseGazette.com

Dear Bridget,
Easiest way it to have her tested for the Dilute/Cream gene. The filly had a 50% chance of inheriting the dilute/cream gene from her mother. Another way would be to look at the mane/tail of the filly – if she is a Palomino the mane/tail should be an extreme flaxen or white color. I’ve seen many different horses of different breeds advertised as Palomino when there was no way they could be – I’d test her to know for sure. - Prism


Dear Prism,
I have a Grullo Stallion and I'm not sure if he is heterozygous for the black gene or not, since I have not had him tested just yet. What color mare would I have to breed him to in order to get another grullo? Just the same, what are some other possibilities for his breeding with other colors? Submitted by Krista Rougeux via HorseGazette.com

Dear Krista,
Well, Grullo is Dun on a black base with no Agouti present. Since you don’t know his red status we will assume that he carries a red gene as well. Your best bet to get a Grullo foal would be to breed him to Grulla mare. The mare would also be Dun on a black base with no Agouti (which limits black to the points). This should also minimize chances of a red foal as well. If your stallion is homozygous for black you will never have a red foal regardless of the mares he is bred to. So your color possibilities for foals out of your stallion would be Sorrel/Chestnut, Red Dun, Black, Grullo, Bay, Bay Dun, I’d have him tested so you know exactly what you are dealing with in the breeding shed. - Prism


Dear Prism,
I have a chestnut mare that I'm breeding to a buckskin Appaloosa that throws 100% color/characteristics. What color possibilities are most likely? – Karen, submitted via horsegazette.com

Dear Karen,
Well the base color of the upcoming foal could be a Sorrel/Chestnut, Bay or Black. If the stallion passes his dilute/cream gene the foal could be Palomino, Buckskin or Smokey Black. It also sounds like the foal would be marked like an Appaloosa. - Prism


Dear Prism,
I have a sorrel mare that is a twin. Her twin is a red roan gelding. I breed her to a gray stud that was born brown. What colors are possible? – Tammy, submitted via horsegazette.com

Dear Tammy,
We know that sorrel is homozygous for red and recent research in France has acknowledged that “Brown” is a form of Black. That means your foal could be Sorrel, Black, Brown or Bay and there would be a 50% chance of the stallion passing along his gray gene. - Prism


Dear Prism,
Do you know what foal colors to expect if I breed a buckskin mare to a bay stallion. The stallions parents were both Grullo. Also, Is having a mare for breeding HYPP/NN a horrible thing or should I stay away from the impressive lines. Thanks, Lazy M Ranch, submitted via horsegazette.com

Dear Lazy M Ranch,
There are a number of variables at play here – if both horses are heterozygous for the black gene (carries one copy) then the foal could be red-based (Sorrel). If one parent is homozygous for the black gene you can rule out red so you’d get a Bay or black. Factor in the dilute/cream gene from the mare and you could get a Palomino, Buckskin or Smokey black. We know the stallion did not inherit the dun gene from either of his parents or he would be a Dun and not a Bay.

And the second part of your question will open a whole can of worms. So what I’m going to say is my opinion and my opinion only.
Impressive bred horses are not a bad thing. They are some of the most athletic horses I’ve ever been around and most of them are flat out beautiful to look at. Impressive is actually one of my favorite bloodlines.

HYPP is the “Bad” thing, not the Impressive bloodlines. I think it is a shame that folks will throw out the baby with the bathwater and declare a whole “family” of horses as bad because of a genetic defect in a few.

HYPP is the genetic defect and it is not a disease. It prevents sodium (potassium) from passing through the muscle membranes and creates an overload of Potassium in the horse’s body. Too much Potassium causes paralysis of muscles and leads to possible death of the horse. There is no cure for a genetic defect and the best owners can do is treat the symptoms. Horses can not “catch” HYPP they have to be born with it. If breeders would stop (as in QUIT) breeding HYPP positive animals the entire species (equid) could be rid of HYPP in one generation.

But most importantly a horse that is HYPP N/N does not have HYPP, will never catch HYPP and will never have offspring which are HYPP positive unless you breed to a HYPP positive horse (and then the HYPP will come from the Positive horse and never from the HYPP N/N horse).
If you like the Impressive bred mare and she brings everything you want to your breeding program then breed her. But don’t be hesitant about breeding an Impressive bred horse which is HYPP N/N because that mare will never pass HYPP to her offspring – she doesn’t carry it. - Prism


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