For you color buffs out there.....
 
 

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For you color buffs out there.....

This is a discussion on For you color buffs out there..... within the Horse Breeding forums, part of the Horse Breeds, Breeding, and Genetics category
  • Color genetics of a bay shire
  • Black horse with white belly spot

 
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    02-12-2010, 01:26 PM
  #1
Green Broke
For you color buffs out there.....

I have a question that is purely whimsical and just for my own curiosity. I know many of you on this forum have a lot of knowledge about different color crosses and what you can expect when you breed X to Y. I know nothing about paint horse variations and stuff, so I thought I'd just put the question out there.

I have a rescue mare (1/2 paint, 1/2 Shire) due to foal in the next month or so (pasture bred so hard to tell). She's a (fading) black tobiano, to the best everyone could tell on the color chart thread . Anyways, she's here:



She is bred to a chestnut Shire stallion that has a white body spot on the side of his belly:





Now she had a colt at heels when I got her, out of the same stallion. The previous colt has been a fading black in his foal coat, with a white spot on his belly as well, but I believe he is going to shed out in the spring as a bay.



Now I know the chances are most likely this new foal will be just like last years, both in color and pattern, and that's what I am expecting. The solid body color with white socks/facial markings/ some underbody or belly spots is a dominant gene with Shires anyways, and since this year's baby, like last years, will be 3/4 I am not expecting any kind of paint pattern.

But I'm curious to know if there might be something else show up? Is it a certainty the foal will be a bay? Could they produce a chestnut, a black, something else? I know there are formulas to predict different color combos and much of it has to do with prior generations, which I know very little about.

This isn't important or anything. Just want to satisfy my own curiosity. Thanks!
     
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    02-12-2010, 06:26 PM
  #2
Weanling
The mare being black means she is "aa" at the agouti locus (she has 2 recessive genes for "not bay"). She is E? At the extension locus-- One dominant E makes black pigment. You can't tell by looking at her if the other e she has is E or e.

The stallion being chestnut means he is "ee" for extension--2 recessive genes for "not black". Since chestnuts have no black pigment for agouti to act upon, you can't tell by looking if he is AA, Aa, or aa at the agouti locus.

If his previous foal from the black mare is indeed a bay, it means he is at least A? And might be AA.

Assuming he is Aa, and asuming the mare is Ee, they could have black, bay, or chestnut offspring. If she is EE and he is Aa, they could have black or bay offspring. If she is EE and he is AA, all of their offspring will be bay.

On top of those base color choices, they could inherit the tobiano gene from the mare-- its a 50/50 chance for every foal she has assuming she's heterozygous for tobi (if any of her foals are not tobi, it means she is heterozygous).

The foal could inherit the sabino/splash form the sire (not sure which he has, ior if he has both).... or the foal could inherit no white-pattern-making genes.

Does last year's foal have any white on his withers or rump, or a white tail? He looks suspiciously like a very minimal tobiano. And FWIW he looks black to me in that photo-- hard to tell though from one wooly pic
     
    02-12-2010, 06:54 PM
  #3
Green Broke
Eastowest ~ ah see you really know your stuff! This is exactly what I was looking for, someone well versed and able to break this down to me in a way I could understand. Thank you so much!

The picture of Finn (last years foal) is from early fall, he was about 8 months old there. I can try to get a current picture of him tomorrow, but as of right now, while his wooly coat on most of his body still looks the same (though more sunbleached/faded) his face has picked up the real coppery brown around his eyes with black eyeliner, and brown muzzle with black-lined nostrils, which is what is leading me to think he will shed out a bay. Then again, his one leg that doesn't have a white sock does not appear black pointed either though. He does have a few white strands mixed in his tail, I'll post a picture where you can see that, but none in his mane, and no other white markings aside from three white socks, belly splash, and the star/snip on his face. Again, from early fall, but here's a side picture showing his white spot on his belly.
     
    02-12-2010, 07:06 PM
  #4
Green Broke
I do not know what any of Freyja's previous foals have come out marked like, all I know is she has had a lot of them, so no way of knowing about the tobiano being heterozygous or homozygous, but I would just assume she is heterozygous.
     
    02-12-2010, 08:44 PM
  #5
Yearling
Looks like to me the stallion is sabino and the mare is tobiano, the foal could get one, both, or neither of these patterns. The last foal looks to be sabino, doesn't look like a tobi. If the foal is black (he looks black to me), the stallion would be either Aa or aa, if he's aa the next foal will also be black, if he's Aa it may be bay. If the foal is bay the stallion is either Aa or AA, if he's AA the foal can not be black. If the mare is homozygous for black the foal will be black or bay, if she's heterozygous the foal may be red. So yes, there is a chance for a different looking baby this year!

I hope that helps!
     
    02-12-2010, 09:15 PM
  #6
Green Broke
Haviris, it does, both of you have been incredibly helpful, you are both so well informed. So thank you! I find the genetics fascinating there is just so little I know about it with regards to horses. I love to learn new things and finding this so educational.

I don't know if this factors in at all, but I was told Freyja was out of a "red and white" paint mare (whether that means sorrel or bay I am not sure) by a black Shire stallion. I have no way of confirming this however since Freyja is a cross and I don't have anything from her parents. I can look up the Shire stallion she is bred to, I have a copy of his ASHA papers around here somewhere, to check some of his background. I know chestnut Shires are less common than black or grey, but I was under the impression pretty much all Shires and Clydes carried the sabino gene?

If Finn (last years colt) does remain black (or fading black) what would the fading around his face indicate? I'll get a good picture of him tomorrow to post, but here's a quick one just yanked off the web in the meantime, this is what his face is looking like with the lightening around the muzzle and eyes:

     
    02-12-2010, 09:26 PM
  #7
Green Broke
Finn has the same coloring as my mare.. I don't know what to call it sorry[:
     
    02-12-2010, 09:43 PM
  #8
Green Broke
Mom and Dad are both Sabino, so you'll probably end up with some color similar to either parent, or maybe even more color than mom. You have a 50% chance of the foal being tobiano or not, and 75% chance of sabino or not. Which breaks down to:
16.67% Solid
33.33% Sabino only
16.67% Tobiano only
33.33% Sabino/Tobiano
The above is assuming the mare is heterozygous for Tobiano.

As far as base color, it depends if the mare is homozygous for black and if stallion carries Agouti or not. Agouti is the bay/brown modifier. If he doesn't and she's heterozygous for black, then you're looking at 50/50 either black or chestnut. If he does and she's heterozygous for black, then you're looking at 50% chestnut, 25% bay, 25% black. If she's homozygous for black, than you're looking at either 100% black or 50/50 black or bay.
     
    02-12-2010, 09:46 PM
  #9
Green Broke
Quote:
Originally Posted by Indyhorse    
I know chestnut Shires are less common than black or grey, but I was under the impression pretty much all Shires and Clydes carried the sabino gene?
Yes, Sabino is what causes those wrap-under blazes and high white stockings. It also causes "roan" Clydes, which are not uncommon.

Quote:
If Finn (last years colt) does remain black (or fading black) what would the fading around his face indicate? I'll get a good picture of him tomorrow to post, but here's a quick one just yanked off the web in the meantime, this is what his face is looking like with the lightening around the muzzle and eyes:

He's definitely not just "Black" with that muzzle. He looks more like Seal Brown. I can also see rather defined black lower legs (though they're high, near the elbows), wich would also point to some brown/bay modifier going on. You could have him tested to find out. The different colleges and genetics labs are slowly creating more and more tests for the different forms of Agouti and other "brown" modifiers.
     
    02-12-2010, 10:33 PM
  #10
Green Broke
Just as an aside, didn't want anyone to misunderstand, the last picture I posted is not of my colt - that's just a picture of a horse with similar facial markings to what Finn appears to be developing. I'll get a proper current picture of Finn to post tomorrow.

Luvs2ride1979 thanks so much for the stats. I was really figuring this next foal would come out looking just like Finn, but I guess there are much greater variables than I was counting on.
     

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