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  1. #1
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    Jan. 25, 2004
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    Default Can Someone Please Help Me Colour Calculate?

    So now that I'm three months into the waiting part of breeding a mare I'm trying to keep myself occupied with all sorts of things like colour lol.

    I've used the colour calculator but I'm not sure if I'm doing it right since I don't know what all the overo, rabicano, sabino etc. means.

    The dam is a solid black mare who is by a bay and out of a black mare. However, her full brother is chestnut with chrome so I assume she is a red carrier?

    The sire is Checkmate who is chestnut with four white socks to just below the knee/hock and a star and stripe.

    I'm wondering what colour the resulting foal might be. Any ideas?

    Thanks for your help!



  2. #2

    Default

    Based on the information given, these are the coat color possibilities:

    33.34% - Black
    33.34% - Bay
    33.33% - Chestnut

    The only way to know more than this is if you got your mare tested for specific genes. Even though the brother is a chestnut, there is still a possibility your mare could be homozygous black (EE), but the only way to tell is if you sent in a hair sample to get tested.

    Coat color calculator here: http://www.animalgenetics.us/ccalculator1.asp
    Last edited by Lorelei Welsh; Oct. 1, 2012 at 06:31 PM. Reason: adding link :)
    Lorelei Welsh Ponies - Visit us on Facebook!
    Breeding show quality Welsh Ponies for the hunters, dressage, in-hand, and more!



  3. #3
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    Default

    Thanks Lorelei - Where does one get a hair sample tested?



  4. #4

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    I actually just sent in two hair samples this morning to this place in Florida to test for the cream gene in two of my ponies and I paid $25/test --

    http://www.animalgenetics.us/Equine.asp

    However, UC Davis also offers this service, with their prices listed on their website:

    http://www.vgl.ucdavis.edu/services/horse.php

    Best of luck to you!
    Lorelei Welsh Ponies - Visit us on Facebook!
    Breeding show quality Welsh Ponies for the hunters, dressage, in-hand, and more!



  5. #5
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    Jan. 5, 2011
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    Default

    I'm not an expert but from what I know: chestnut is the most recessive color, black is second most recessive.
    If B=bay and b=black and c=chestnut, it seems to me the grandparents who produced a black and a chestnut would have to be genetically: Bay stallion Bc & black mare bc
    and your black mare would then be bc. (Brother is cc.)
    Cross a bc with a chestnut cc and your chances are 50% black and 50% chestnut.
    I actually don't think genetic testing could tell you anything more than bay + black = chestnut & black does. Kind of weird that there weren't any bay foals (or were there?) And I can't think of any genetic way that you could have 33% odds of any result.



  6. #6

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    Quote Originally Posted by OTTBs View Post
    I'm not an expert but from what I know: chestnut is the most recessive color, black is second most recessive.
    If B=bay and b=black and c=chestnut, it seems to me the grandparents who produced a black and a chestnut would have to be genetically: Bay stallion Bc & black mare bc
    and your black mare would then be bc. (Brother is cc.)
    Cross a bc with a chestnut cc and your chances are 50% black and 50% chestnut.
    I actually don't think genetic testing could tell you anything more than bay + black = chestnut & black does. Kind of weird that there weren't any bay foals (or were there?) And I can't think of any genetic way that you could have 33% odds of any result.
    I edited my post just as you added a comment to include the link to the color calculator I sometimes use. It comes in handy, a great little tool when you are trying to figure out the 'what ifs'!

    http://www.animalgenetics.us/ccalculator1.asp
    Lorelei Welsh Ponies - Visit us on Facebook!
    Breeding show quality Welsh Ponies for the hunters, dressage, in-hand, and more!



  7. #7
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    Default

    Thanks OTTB.
    I don't think that cross what done a third time, however I know that the stallion has produced bays. Not sure what the dams were.

    Would that change the odds?



  8. #8
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    Feb. 7, 2005
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    Default

    Quote Originally Posted by OTTBs View Post
    I'm not an expert but from what I know: chestnut is the most recessive color, black is second most recessive.
    If B=bay and b=black and c=chestnut, it seems to me the grandparents who produced a black and a chestnut would have to be genetically: Bay stallion Bc & black mare bc
    and your black mare would then be bc. (Brother is cc.)
    Cross a bc with a chestnut cc and your chances are 50% black and 50% chestnut.
    I actually don't think genetic testing could tell you anything more than bay + black = chestnut & black does. Kind of weird that there weren't any bay foals (or were there?) And I can't think of any genetic way that you could have 33% odds of any result.
    Because it doesn't work quite like that. There are two genes at play - first is Extension (determines black vs red). E = black (dominant) e = red (recessive)

    Black mare in this case is either EE or Ee. We cannot determine which without more information.

    Chestnut stallion in this case must be ee.

    Second gene is Agouti. A = pushes black pigment to the points (dominant, turns a black horse bay) and a = does not push black pigment to the points.

    So mare is either EEaa or Eeaa.

    Chestnut stallion could be eeAA, eeAa, or eeaa. Since Agouti does not act visibly on a red coat, we do not know his Agouti status without further information.

    (This is a simplified version of reality - Agouti can also be responsible for wild bay, seal brown.)

    I'm not going to work out all the Punnett squares, but I'm sure if you consider all the variations the 33% chance of bay, black, or chestnut is about right. That could change if we have more information - if we knew the stallion was eeaa, then we would know for sure there can't be any bay foals.



  9. #9
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    Default

    Quote Originally Posted by Hony View Post
    Thanks OTTB.
    I don't think that cross what done a third time, however I know that the stallion has produced bays. Not sure what the dams were.

    Would that change the odds?
    No, we would need to know what color the mares are. And really, we would need to know if he has produced bay from a black mare before to say anything for certain.



  10. #10
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    Default

    Okay,this all sounds very complicated. I think I'm just going to hope for a black horse or a bay horse or if I have to have a chestnut then I'd like some chrome. Thanks for all your help though!



  11. #11
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    Dec. 13, 1999
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    Default

    Quote Originally Posted by Hony View Post
    The dam is a solid black mare who is by a bay and out of a black mare. However, her full brother is chestnut with chrome so I assume she is a red carrier?
    You can't assume she is EE or Ee (homozygous black or heterozygous) based on a full brother. If one if their parents was chestnut, then you'd know she is Ee. However, both parents are Ee, and each of them had a 50/50 shot at giving their E or their e.

    This means she had a
    - 25% chance of being chestnut, because it would take both parents giving their e
    - 37.50% chance of being black, because only 1 parent had to give the E and the bay parent had to give the a (Agouti, which in the A form makes a black horse a bay), and because she's black we know the bay parent is not homozygous Agouti, and is Aa.
    - 37.50% chance of being bay, because only 1 parent had to give E and the bay parent had to give A

    The sire is Checkmate who is chestnut with four white socks to just below the knee/hock and a star and stripe.
    We know she is aa for Agouti. We don't know if she's EE or Ee.

    If she is EE, then all you know for sure is she won't have a chestnut foal, not with Checkmate, not with anyone.

    If she's Ee, then it's a 50% chance of chestnut - Checkmate can only pass e, and she has a 50/50 shot at passing e as well.

    If she passes her E, then you know the foal will black-based.

    Checkmate's sire Check In is brown, which gives you an interesting option of potentially a brown foal. But his dam Evita doesn't have a color listed on horsetelex so that's a big open unknown. Her sire was brown and her dam chestnut. This gives a fairly strong possibility that Checkmate is at least Ata (heterozygous for brown), but he could be AAt (1 each of bay and brown), and he could be AA or even aa. So, not much help there, and that's your biggest unknown.

    So, that said, your choices are black, bay, brown, and chestnut. The only known entity is a 25% chance of chestnut. The other 75% is made up of some variances of black, brown, and bay, and without knowing Checkmate's status, the % of each can't be determined.
    ______________________________
    The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET



  12. #12
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    Smile

    Quote Originally Posted by OTTBs View Post
    I'm not an expert but from what I know: chestnut is the most recessive color, black is second most recessive.
    Chestnut - "red" - is the only recessive in this context. Black is dominant over red every time.

    Chestnut is a "recessive" color because it takes the horse being homozygous for the red gene, e, to be red-based.

    Black color isn't recessive - it's just less common because it takes the horse being Ee or EE (hetero or homozygous black) AND being aa for Agouti.

    If B=bay and b=black and c=chestnut, it seems to me the grandparents who produced a black and a chestnut would have to be genetically: Bay stallion Bc & black mare bc
    and your black mare would then be bc. (Brother is cc.)
    Cross a bc with a chestnut cc and your chances are 50% black and 50% chestnut.
    It doesn't work like that because you don't have the right breakdown. Red and black are controlled by a single gene - Extension. Each horse gets 1 copy from each parent: It's either E or e. E means the horse is black-base (not necessarily black). e means there's a chance the horse can be red-based, but it depends on the other copy: ee would be red-based, Ee would be black-based.

    Bay comes from a separate gene - Agouti. A (bay) or At (brown) takes an E? horse and makes him bay or brown. It has no effect on an ee (red-based) horse.

    I actually don't think genetic testing could tell you anything more than bay + black = chestnut & black does.
    Huh? Of course it can. Genetic testing tells you everything about the black/red status, brown/bay status, silver, dun, gray, roan, cream, and more.

    We absolutely know some things from the above equation, which is that both parents are Ee - they are both black-based (bay and black) so each have an E, and to produce a chestnut they both have to have an e as well - makes both of them Ee.

    But since chestnut does not express any form of Agouti, we cannot know the Agouti status of either the bay parent or the chestnut foal, *other than* the chestnut foal cannot be homozygous for Agouti (because the black parent only had "a" to give, therefore the chestnut foal from that cross can only be Aa or aa).

    But if you test that chestnut foal, you'd know whether he's Aa or aa, and if he's Aa, if you test at Pet DNA, you'd know if he's Aa or Ata.

    The black foal can only be aa - don't need any testing to know that. But because he's by parents who are known Ee, we don't know if he's Ee or EE, and genetic testing absolutely easily tells us which he is.

    So yes, genetic testing tells us a LOT more than we might otherwise know from phenotype or the parents' phenotype or even the parents' genotype

    Kind of weird that there weren't any bay foals (or were there?)
    By/out of who? I got lost on this LOL

    And I can't think of any genetic way that you could have 33% odds of any result.
    I'm fairly certain there is, since the remainder is 67% which can easily be accounted for by all sorts of variables that we haven't even touched on - splash, tobiano, silver, cream, etc. You can get % down to a sub-1% possibility. Go to the and put in on parent being perlino, one being buckskin, unknown Agouti and Extension status, both being tobiano/splash/sabino, and have fun with all the potential combinations
    ______________________________
    The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET



  13. #13
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    Jan. 5, 2011
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    Default

    I knew I oversimplified my original post. I'm going to have to study my color genetics book some more.
    Quote Originally Posted by JB View Post
    Quote:
    Kind of weird that there weren't any bay foals (or were there?)
    By/out of who? I got lost on this LOL
    By the bay stallion. Seems he should have a 50% chance of bay foals, but we initially only knew of a black and a chestnut.

    Quote Originally Posted by JB View Post
    I'm fairly certain there is, since the remainder is 67% which can easily be accounted for by all sorts of variables that we haven't even touched on - splash, tobiano, silver, cream, etc. You can get % down to a sub-1% possibility. Go to the and put in on parent being perlino, one being buckskin, unknown Agouti and Extension status, both being tobiano/splash/sabino, and have fun with all the potential combinations
    Since genes occur in pairs, I don't see how there can be 33% odds in reality. Maybe all those "unknowns" you mention can cause odds like that. And then there's the other thread where the horse appearing to be a bay tobiano is a black with the silver gene... I don't think the silver gene even made it into the book I have.



  14. #14

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    Quote Originally Posted by OTTBs View Post
    I knew I oversimplified my original post. I'm going to have to study my color genetics book some more.

    By the bay stallion. Seems he should have a 50% chance of bay foals, but we initially only knew of a black and a chestnut.


    Since genes occur in pairs, I don't see how there can be 33% odds in reality. Maybe all those "unknowns" you mention can cause odds like that. And then there's the other thread where the horse appearing to be a bay tobiano is a black with the silver gene... I don't think the silver gene even made it into the book I have.
    Here is the breakdown in percentages with the genes for the potential offspring:

    Ee/Aa = 33.3350% (Black)
    Ee/aa = 33.3350% (Bay)
    ee/Aa = 16.6650% (Chestnut)
    ee/aa = 16.6650% (Chestnut)
    Here is the breakdown of the sire and dam (what information was given about them - anyway)

    Sire:

    Sire Color: Chestnut/Sorrel
    Agouti: aa, Aa, AA (could be any of these)
    Red Factor: ee
    Dam

    Dam Color: Black
    Agouti: aa
    Red Factor: Ee, EE (could be either of these)
    Hope this helps.
    Lorelei Welsh Ponies - Visit us on Facebook!
    Breeding show quality Welsh Ponies for the hunters, dressage, in-hand, and more!



  15. #15
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    Default

    I don't want to confuse things - but you also need to make sure that the 'black' dam is indeed a true black (ie. gg EE/Ee aa) and not a very dark bay/brown (ie. EE/Ee AA/Aa).

    Edited to add: As I found out - you can't always go by the look of the horse in front of you or their registration papers
    Last edited by mikali; Oct. 2, 2012 at 03:10 PM.
    Alison/Mikali Farms
    www.mikalifarms.com



  16. #16
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    Genes occurring in pairs in no way means outcomes are only in even percentages . You can get sub-1% chances, 1/2% increments, 1/4% increments, etc. it all depends on how many variables you're throwing into the pot.
    ______________________________
    The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET



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