grey x bay

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loubylou

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Oct 21, 2008
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I am considering eventually (talking a few years time) putting my grey mare to a dark bay stallion (stallion stands on a stud where my horses are kept, so he is already chosen if I do eventually do this)

My question- If I understand genetics correctly, I know grey is dominant, and as my mare is a chestnut x grey originally (and a funny grey type colour at moment as a youngster) she is carrying one dominant grey gene, and one chestnut gene (correct?) The bay with therefore definately have NO grey genes (correct?) I understand that in all liklihood the baby will be grey, but is there a chance he/she would be bay or chesnut, and how would I measure this? is there anything more dominant than the grey gene?? And if she is put to a dark bay, would the foal therefore be an iron grey?? Sorry lots of questions, but am trying to get my head around colour and genetics- I am getting there!!

Please dont have a go at me about breeding my mare- she is well bred, as is the stallion, and its something I wouldnt do without a bit more information under my belt, I am just asking out of curiosity!
 
There is 50% chance that the foal will be grey. Don't ask my the % of the likelyhood of1 chestnut/bay/black becuase that's where it get complicated! I'm not sure about the iron grey bit though. I would expect the darker the base colour the darker the foal, but I had 1 born black last year who went quite light
 
Gurnosstud said:
There is 50% chance that the foal will be grey. Don't ask my the % of the likelyhood of1 chestnut/bay/black becuase that's where it get complicated! I'm not sure about the iron grey bit though. I would expect the darker the base colour the darker the foal, but I had 1 born black last year who went quite light
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ditto that :)
 
loubylou said:
My question- If I understand genetics correctly, I know grey is dominant, and as my mare is a chestnut x grey originally (and a funny grey type colour at moment as a youngster) she is carrying one dominant grey gene, and one chestnut gene (correct?)
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She has at least one copy of chestnut. Do you know what colour she started out? If she started out chestnut, she has two copies of chestnut and can only pass chestnut on to a foal. If she started out bay or black, she only has one copy of chestnut so could also pass on black base to a foal. If she has bay in there too (she could carry bay and still be chestnut if she has no copy of black) she could also pass bay on.

loubylou said:
The bay with therefore definately have NO grey genes (correct?)
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Absolutely. He cannot pass grey on and since we know your mare only has one copy of grey, that puts your chances of a grey foal at 50/50.

loubylou said:
I understand that in all liklihood the baby will be grey, but is there a chance he/she would be bay or chesnut, and how would I measure this?
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As said, it's a 50% chance of grey. There may be a chance of a chestnut foal; we know your mare has at least one copy of chestnut but the chance of chestnut rests on whether or not the stallion has a hidden copy. If he does, you have either 25% or 50% chance depending on how many copies your mare has (we know the stallion, if he does have a copy, will only have one since he's not chestnut). If stallion has no chestnut, you're gurarnteed either black or bay foal.

loubylou said:
is there anything more dominant than the grey gene?? And if she is put to a dark bay, would the foal therefore be an iron grey?? Sorry lots of questions, but am trying to get my head around colour and genetics- I am getting there!!
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Grey is a simple dominant. If a horse carries grey, it will go grey. Black or bay based horses are sometimes darker to start with, but all greys eventually end up white. Some end up white faster than others - we have a grey Sec A who was completely white by six years old, but Gelfy, also grey, was into his teens before he became white.
 
Thanks so much Chev- that has really cleared things up for me! genetics is far more interesting than I ever realised!
She was chestnut to start, and is even listed as a chestnut in her passport. At the moment she is a very very dark grey (winter coat) but was identified as a grey by yourself a while back (which is when i first became a little more interested in the genetics of it all :) )

I dont know about the stally, but am sure I could find out, i am pretty sure he is from a bay and a black, but cant be 100% sure- would have to ask!

Thanks all

x
 
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