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| So you want to breed and are wondering what color you can expect when breeding your mare to Seminole. To be blunt, a lot depends on your mare and what her genetics for color are (as you will see in the table below). The easiest way to find out about her genetics is to have her tested. It's just like the DNA test we do for parentage except this time they are looking at the color genes. Testing for the Agouti (Bay/Black) and Extension (Red) genes costs $50 from UC Davis. More information about their testing can be found at their web site ( www.vgl.ucdavis.edu/horse/redfactr.htm ). They have forms online that can be printed off and mailed along with a hair sample and the payment. If you provide your e-mail address then they will e-mail the results to you several days before you get a hard copy in the mail. Of course sometimes you don't need to pay to get a mare tested because you know enough about her parents and the foals that she has produced to be able to figure all the genetics out yourself. About half way down this page I will take you though that process. Below is a table to help you figure out what the probabilities are of various colors being produced when you breed your mare to Mountain View's Seminole. I have only included colors common to the Rocky Mountain Horse. If you have a mare that is some other color and want to know what to expect please contact me and I'll figure it out for you. Seminole HAS been DNA tested for color and is genetically Eeaa. Also since his dam was a bay (did not carry silver dapple gene) we know he is only cysted (Zz). Below the first table I will try to help you figure out what hidden genes your mare might have. You will need to know this information to get an accurate idea of what foal colors to expect. I give a little background information about the genes involved and then work you through step by step to determine the hidden genes your mare carries. The questions are broken up based on base coat color. Determine her base coat color and then work through the questions for that base coat (read them carefully). Write down your answers they will be needed in the table below. In the table below I assume that black, bay and normal eyed chestnuts do not carry the silver dapple gene (Z). I assume that a chocolate or red chocolate with cysts or normal eyes carries one copy of the silver dapple gene and that horses with ASD carry two.
FIGURING OUT THE GENOTYPE OF A MARE First figure out what base coat color you have All coat colors can be broken down into one of three base coat colors (black, bay, chestnut) and then the addition of various modifier genes. Most of the modifier genes either leave the base coat color completely alone and just put white spots or mix in white hairs (sabino, tobiano, roan) or they lighten the base coat color in some way (palomino, buckskin, chocolate, red chocolate, dun, grullo). These genes are easy to deal with. If white hairs or spots are in the way then just image the horse without the white hairs. In the case of a roan for instance look at her face to figure out the base color of the body. Then imagine the horse with it's entire body that color to figure out what you have. In the case of the genes that lighten color imagine the horse with the brown/chocolate areas of it's body turned black or the golden areas of it's body turned red. Just to give you a little help, here are some of the common colors and their corresponding base coats:
The exception to that is the smutty gene and they can turn a bay horse almost black in some cases but usually is seen as a 'chocolate' with black mane, tail and lower legs. Some people call this seal brown. It can also turn a red chocolate into what appears to be a chocolate but won't produce like a chocolate. It helps to know what the horse looked like as a foal. If it ever looked bay or red chocolate but now is being passed off as black or chocolate then there is a good chance that it is a bay or red chocolate with a smutty gene. Another indication is if the color on the legs versus the body is different but this can also be due to sun fading. You should be able to see the color change where the black stockings on a bay would be. Basic rule of thumb is if in doubt figure it as base coat bay unless BOTH parents were definitely base coat black. Now figure out the hidden stuff Unfortunately, you have to be a bit more of a detective to figure out the hidden genes. Genes come in pairs and your horse gets one of that 'type' of gene from it's mother and one from it's father. All the genes I'm going to be talking about are either dominant or recessive. In the case of a dominant gene you only need one of that type to see that trait in your horse. It does not matter what the other parent gave so you don't know if the other gene is dominant or recessive. On the other hand if you can SEE the recessive version of the trait in your horse then you KNOW that BOTH genes are the recessive. In genetics they symbolize a recessive gene with lower case letters and a dominant gene with upper case letters. The Extension and Agouti Gene The genes we are worried about in order to decide the base coat color are the Extension gene and the Agouti gene. The dominant of the Extension gene (symbolized E) means that the horse will have black (or chocolate) somewhere on their body. The recessive of the Extension gene (symbolized e) dictates that the horse will not be able to produce the color black ANYWHERE on itself. So if a horse gets two copies of that gene then its base coat color will be chestnut. The second gene we are concerned with is the Agouti gene. Its affect is only seen if the horse is not chestnut. The dominant of the Agouti gene (symbolized A) restricts the black on the horse's body to the points (mane, tail and lower legs). This creates a bay base coat horse. The recessive of the Agouti gene (symbolized a) allows black on the entire horse. This creates a black base coat horse. Blacks and Chocolates If you have a black or chocolate mare then you already know that you carry two copies of the recessive Agouti gene (symbolized by a lower case a). You also know that you carry at least one copy of the dominant version of the Extension (red) gene (symbolized by an upper case E). What we don't know is what that other extension gene is. Here is where the detective work comes in. Remember the following questions refer to BASE coat color so refer to the table above on base coat colors if in doubt. Step 1. Did EITHER parent have a chestnut base coat color? If the answer is YES then stop here. We KNOW the answer. Your horse DOES carry red. You do not need to do any DNA testing because you have your answer. If the answer is NO then go to step 2. Step 2. Has your horse EVER produced a chestnut base coat color foal? If the answer is YES then your horse DOES carry red. You do not need to do any DNA testing because you have your answer. If the answer is NO then you don't know for sure. Your horse MIGHT not carry red, or it might have been being bred to a horse that did not carry red (both parents must carry the recessive Extension gene for the offspring to be chestnut), or you might just be lucky so far. The easiest way to know for sure is to do DNA testing. MOST Mountain Horses DO carry red. Chestnuts If you have a chestnut mare then you already know that you carry two copies of the recessive Extension gene (symbolized by a lower case e). You have no idea what the Agouti genes are however because there is no black on your horse to see if it is on the points or the entire body. This is harder to figure out then the previous example because there are TWO unknown genes (BOTH Agouti genes). Step 1. Did BOTH parents have a black base coat color? If the answer is YES then stop here. We KNOW the answer. Your horse carries TWO copies of the recessive Agouti gene. This is great news for you because that means that if you cross with a black base coat stallion that does NOT carry a red gene then you will only produce black base coat foals. You do not need to do any DNA testing because you have your answer. If the answer is NO then go to step 2. Step 2. Did ONE parent have a black base coat color? If the answer is YES then we KNOW that your horse carries at least one recessive Agouti gene. We still have to figure out the other gene though. You can skip step 3 and go to step 4. If the answer is NO then we still don't KNOW anything about either of the Agouti genes. Go to step 3. Step 3. Has your horse EVER produced a black base coat color foal? If the answer is YES then we KNOW that your horse carries at least one recessive Agouti gene. We still have to figure out the other gene though. Go to step 4. If the answer is NO then we still don't KNOW anything about either of the Agouti genes. Go to step 4. Step 4. Has your horse EVER produced a bay base coat color foal when bred to a BLACK base coat stallion? If the answer is YES then your horse DOES carry at LEAST one copy of the dominant Agouti gene. If the answer to step 2 or 3 above was YES then you KNOW both genes (one dominate and one recessive Agouti gene) and you do not need to do any DNA testing because you have your answer. If the answer to step 2 or 3 above was NO then you don't know if the second gene is dominant or recessive. You do KNOW that you either carry ONE recessive Agouti or no recessive Agouti genes (you know that you could NOT carry two recessive Agouti genes because you answered yes to this question so you have to carry at least one dominant Agouti gene). To know the complete answer you would need to do DNA testing or wait until more foals were born. If the answer is NO then you don't know anything more for sure. If the answer to step 2 or 3 above was YES then you KNOW one of the genes is the recessive Agouti gene. To know the complete answer you would need to do DNA testing or wait until more foals were born. If the answer to step 2 or 3 above was NO then you don't know anything for sure. The easiest way to know for sure is to do DNA testing. Bays and Red Chocolates If you have a bay base coat color mare then you already know that you carry one copy of the dominant Extension gene (symbolized by an upper case E) and one copy of the dominant Agouti gene (symbolized by an upper case A). Like the chestnuts this leaves us with two unknown genes to figure out but a different set of questions. Step 1. Did EITHER parent have a chestnut base coat color? If the answer is YES then we KNOW the answer for the extension gene. Your horse DOES carry red (recessive version of extension gene). Go on to step 3 to figure out the unknown Agouti gene. If the answer is NO then go to step 2. Step 2. Has your horse EVER produced a chestnut base coat color foal? If the answer is YES then your horse DOES carry red (recessive version of extension gene). Go on to step 3 to figure out the unknown Agouti gene. If the answer is NO then you don't know for sure. Your horse MIGHT not carry red, or it might have been being bred to a horse that did not carry red (both parents must carry the recessive Extension gene for the offspring to be chestnut), or you might just be lucky so far. The easiest way to know for sure is to do DNA testing. MOST Mountain Horses DO carry red. Go on to step 3 to figure out the unknown Agouti gene. Step 3. Did EITHER parent have a black base coat color? If the answer is YES then we KNOW that your horse carries one recessive Agouti gene and one dominant Agouti gene. Stop here. If the answer is NO then we still don't KNOW anything about the second Agouti gene. Go to step 4. Step 4. Has your horse EVER produced a black base coat color foal? If the answer is YES then we KNOW that your horse carries one recessive Agouti gene. If the answer is NO then we still don't KNOW anything about the second Agouti gene. The easiest way to know for sure is to do DNA testing.
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