What color will a paint produce? Why is the foal a solid color? What is homozygous?

paint and foalThis photo showed up on my Facebook page with the question, “Why didn’t the mare have a pinto foal?”

Color is a complicated subject most of the time. I wrote a blog about what colors Roxy produced which also included a link to a “coat color calculator” which is an interesting tool to play with.

If one of the horses involved is homozygous for a dominant color or color trait then things get a little easier because you can guarantee that all the foals produced will carry that trait. In paint horses it is possible to have a homozygous paint but just because a horse is a paint doesn’t guarantee it will produce color. The paint horse shows even have classes for solid Paint bred horses.

Here is a link to a page about what creates a homozygous Paint horse. I also found this page that has some great info on homozygous or not homozygous as it relates to many colors including black, dun, roan and gray…it is an interesting read.

If predicting color were easy I would be a happy camper! Someday I want to have a painted reining horse but for now I am sticking with versions of dun due to genetics. Why do I say this? Because Roxy’s mother was a dun and all the foals she produced, except Roxy, were black pointed duns. Roxy’s sister, Maggie, shown in the video below has produced 100% duns so far with Newt being a red dun and all others being black pointed duns.



  1. cowgirlmichaela on July 17, 2014 at 2:55 pm

    This website is pretty interesting, and is not too difficult to understand if you try hard enough: http://draftswithdots.blogspot.com/2010/07/basics-of-horse-color-genetics.html

  2. Kelly Hand on July 16, 2014 at 8:26 pm

    I knew a mare that was a grey Percheron bred 4 times to a bay Morgan. The resulting colors were black and white tobiano, buckskin tobiano, black, and buckskin. Figure that out. Lol

  3. cowgirlmichaela on July 15, 2014 at 11:44 pm

    I agree with everyone on not caring too much about the color.
    I have done a ton of research on genetics. Basically, every horse has two copies of each color gene.
    Within each of those genes, the color is either dominant or recessive. Think of dominant as the ‘on’ switch; either one or both of the two genes could be ‘on’. If all genes are ‘off’, or recessive, the horse is chestnut. Most horses have pretty much all of the genes ‘off’.
    Homozygous means that we know that both of allelles (the different copies of color within the gene) are the same, either dominant or recessive. Heterozygous means that one allelle is ‘on’, and one allelle is ‘off’.
    By looking at the foal and the mother together, the foal tells us a lot about the dam. Because when a horse is bred, each gene splits so that the foal inherits one allelle from each parent.
    Because the mare is a tobiano and her foal is not, that means the the dam has to be heterozygous for tobiano. She also must be heterozygous for black, because the foal isn’t black. The foal inherited both of the ‘off’ genes.
    Being heterozygous simply means that the foal (now talking about future ones) could have either inherited the ‘on’ or the ‘off’ switch.
    As a side note, because the foal inherited the ‘off’ switch, he can’t pass it on to offspring. Horses either have it or they don’t.
    Sorry. I just needed a moment to geek out there.

    • Annie Gass on July 17, 2014 at 6:41 am

      I completely agree, but there are some exceptions to the idea that an allele must be either dominant or recessive. I don’t have Michaela’s knowledge of equine generics, but in cats there are several examples. There is one gene that has FOUR different mutations. The least dominant of the four is albino; the most dominant we can call “intense”. Between them in order of dominance are Burmese (solid dark brown) and Siamese (light body, dark face, ears, legs, and tail) Those two are co-dominant, so a cat with one of each will be an intergrade between the two that cat people call “Tonkinese”. They can never breed true. If you don’t already know what they look like you can look at each type with Google images. Does anyone know of a similar situation in horses?

      • cowgirlmichaela on July 17, 2014 at 2:54 pm

        I don’t think I’ve ever heard of a horse mutation that would cause a horse to not be able to breed, although there are certain colors you should avoid breeding. For example, all frame overo horses are heterozygous; if a horse inherits both copies of that gene, it is called LWOS, or Lethal White Overo Syndrome. Not much is known about it, but the foal is born white and dies within 48 hours of being born. So breeding two overo’s is pretty much off-limits; the risk of having a homozygous foal is 25%, with heterozygous being 50%.
        I don’t know much about different mutations, but different genes will react when pared with other genes. Like a horse with an E gene (black) will be black, but a horse with an E gene plus an A gene (bay) will make bay. But a bay gene without the black is nothing.
        That is interesting about the cats; I’ve never heard of different almost mini-genes within horses like that in which each one has an order of dominance.

    • Wanda Ennis on June 24, 2023 at 7:27 pm

      Thank you so much. I know nothing about horses. But I want to learn. I have experience breeding/showing Australian Sheppards. Which helped me understand a little.

  4. Brenda on July 15, 2014 at 8:23 pm

    I have a friend that has a stud that is homozygous for toboino and black and also carries the cremello dilution that really starts narrowing things down. I have a stud that is gray and white homozygous for tobiano and is mostly throughbred he is making some pretty pretty babies my bay roan paint mare always has thrown roan

  5. Annie Gass on July 15, 2014 at 5:40 pm

    There’s an old, old horseman’s saying, “A good horse can’t be a bad color.”

    There are at least six different genes for white spotting in horses, and some are recessive, which means that a horse could carry that gene but not show any white. But it could still throw a spotted foal. Just as likely, a spotted horse with a dominant spotting gene could throw a solid foal. Then there are the ones who carry several different spotting genes, which can make chaos out of any color-prediction calculations! Genetic testing can identify which gene(s) a horse has and the PROBABILITY of any given outcome, but it can’t usually actually PREDICT the color of a foal.

    Also, mutations happen. Thus the occasional quarter horse from traditionally solid lines, but with a big white spot on his belly. Last time I checked that horse couldn’t be registered quarter horse, but COULD be registered paint. Last night (coincidentally) I discovered quite a few horses who are double-registered pinto and Thoroughbred!!! Some are VERY colorful! For several hundred years it was believed that a T-bred COULDN’T be pinto; as a matter of fact there are check-boxes for color on Jockey Club applications for registration, but none for pinto (or palomino, or any of the other fancy colors they’ve got now.) These horses are DNA tested – they are not crossbreds! Google “pinto thoroughbred” to see some examples.

  6. pferdeakademie on July 15, 2014 at 5:24 pm

    I agree with dustybooscorral ( I can’t see breeding only for color, but if you can find the attributes you want in the color you want, why not give it a try.) but…. I’ve seen many horrendous results when people just bred for color without any thought to temperament, working attitude or even physical composition. A lot of those horses turn up in my training (or other trainers) as problemhorses. Usually you can turn them around with a lot of hard work and then they are great. I just think it could be so much easier for everybody (horse and human) if people paid a little more attention to other details than just a nice color.

  7. dustybootscorral on July 15, 2014 at 5:04 pm

    I bred my red dun mare with a cremello stallion for color and got the palomino I was looking for. The stallion also had the foundation QH breeding and temperament I wanted, as does our now 8 year old gelding. Then I wanted a cremello QH mare to breed palominos, and looked all over the country via internet to find one with foundation breeding and a very calm disposition. She was a near-yearling 2,000 miles away and I was hoping for a more local mare, but she grew up into such a brave, calm, curious horse I couldn’t have asked for better. The bottom fell out of the amateur horse market before she matured so we’ve never bred her. Kind of a shame with her lovely long blond mane and a “spook” that generally consists only of a one-shoulder hunch, then a laid back “oh, ok’. I can’t see breeding only for color, but if you can find the attributes you want in the color you want, why not give it a try. Of course in your case the attributes are a whole lot more specific than those of many others.

  8. Maurene on July 15, 2014 at 1:58 pm

    Breed for brains and heart. Be happy with what ever color that is

  9. Kimi B on July 15, 2014 at 1:51 pm

    we’ve only bred twice, using the same stallion, and it was for brains. It was just a happy coincidence that we ended up with exactly what we wanted color wise. A palomino out of a sorrel and a buckskin from a bay. pure luck.

  10. syepez1999 on July 15, 2014 at 1:41 pm

    Hi Stacey my name is Savannah Yepez and I have admired you since the first day I saw you ride your horse saddles and bridaless you are an amazing horse women haha but I could really use some tips on how u managed to keep your balance please email me back thank you.

    Sent from my Galaxy S®III

    • Stacy on July 20, 2014 at 6:09 pm

      Savannah-I have it in my notes to write a blog about keeping your balance when riding bareback. Keep watching for that one and I will also try to remind you when it comes out.

  11. coolstorymoose on July 15, 2014 at 1:10 pm

    As i always say, you can’t ride color. Meaning, dont pick a horse for its color, pick it for its temperament or training etc. A solid (boring ;p ) bay might be the better horse than a fancy paint or pretty palomino. The color is just the cherry on top. 😛

  12. Jackie on July 15, 2014 at 12:58 pm

    So a solid color horse who’s parents are paint is a paint horse?

  13. Jan on July 15, 2014 at 12:35 pm

    Breeding horses for color is a crap-shoot, at best. But sometime one comes along that is a real mystery….one that just can’t be solved, I guess.


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