# Grey Stallion, Chestnut mare.



## Daisychain (20 May 2008)

Which is more dominent in this match, the chestnut or grey gene, or is it just 50/50? thanks.


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## eventrider23 (20 May 2008)

the grey I woud say as the foal could well be born chestnut and go grey in time  It would of course depend though on whether the horse were homozygous or heterozygous for the relevant genes tho


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## minmax (20 May 2008)

I don't know the sience bit but my horse is chestnut, out of a chestnut by a grey. He has 2 full sisters, they are grey.


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## JanetGeorge (21 May 2008)

If one parent is grey - and not homozygous for grey - then you have a 50% chance the foal will grey - whatever colours are involved. (Grey is not a colour gene but a colour modifier.)  If the foal does NOT carry the greying gene, then the colour depends on what colour the grey parent is UNDER the grey.


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## Gingernags (21 May 2008)

I knew ours was 50-50 when I bred Asti as he had a few bays and chestnuts on the ground already.  Stallion was grey, Asti's mum was chestnut - and I got my second generation chestnut mare.

Now just crossing fingers for a third generation chestnut filly but with a spotty botty!

(I just know I'm going to have a leopard colt...)


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## cruiseline (21 May 2008)

As stated by JanetGeorge, grey is not a colour, it is a colour modifier.

If the grey horse is homozygous for the grey gene, meaning that it has been given a grey gene by its mother and a grey gene by its father, It will always produce a foal that will grey out. A white grey horse is usually considered homozygous and a fleebitten horse is usually considered as carrying one grey gene.

A chestnut mare put to a chestnut stallion will always produce a chestnut foal.

So if the grey stallion you are talking about has a base coat of chestnut and is not homozygous for grey, you will get 100% chestnut foal with a 50% chance that it will carry the grey gene and grey out.l


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## Gingernags (21 May 2008)

So when I bred mine (original mare), stallion obviously not homozygous for grey but must have carried a recessive chestnut gene - the filly had to get 2 recessive genes for chestnut - 1 from each side - to stay chestnut (she's 16 now, not figuring she'll grey out at this stage!)

But for him to have say bay foals from bay mares, that didn't grey out, he'd have passed on the recessive chestnut gene, and the bay gene from the mother would be dominant?

The babies that did grey out, he'd have passed on the other gene that was then modified by the grey?

I have to ask this question about solid colours as I've no hope in hell of understanding the appaloosa genetics as its all so random!  At least I stand a chance of "getting" this!


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## c7mlm (21 May 2008)

at our yard we have a 4yo strawberry roan sort of colour very pretty. mum was a skewbald father a grey.


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## cruiseline (21 May 2008)

[ QUOTE ]
So when I bred mine (original mare), stallion obviously not homozygous for grey but must have carried a recessive chestnut gene - the filly had to get 2 recessive genes for chestnut - 1 from each side - to stay chestnut (she's 16 now, not figuring she'll grey out at this stage!)


[/ QUOTE ] 

Yes, is the answer to your question.

Ok I will try to get this right for you.

There are only two basic coat colours of horses RED factor and BLACK factor.

A chestnut horse is genetically considered as being 'RED factor' 
A red horse will have received a red gene from both its mother and father and will only ever pass on a red gene to its offspring.

A bay/black horse is genetically considered as being 'BLACK factor' 
A black horse could carry a red gene, which is hidden. If the black horse has one red parent it is guaranteed to have one red gene, and will pass on that red gene 50% of the time to its offspring.

But also a black horse could have 2 black genes and therefore would never produce a red, even when put to a red horse, but the offspring of a red/black mating will carry the red gene from the red parent.

It does get a lot more complicated as you get deeper into the genetic make-up of a horse.

The colour modifing genes are:-

Grey gene
Dilute gene
Dun gene
Roan gene
Silver dapple gene
Tobiano gene
Overo Gene
Appaloosa gene  -  I can't comment on the Appaloosa gene as I have no knowledge of how that works, it complicated apparently.

(have I forgotten any??????????)

All the above mentioned genes modify the basic coat colour of RED or BLACK.


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## jaffs (21 May 2008)

http://www.horsetesting.com/CCalculator1.asp  try this, might help....


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## KarynK (21 May 2008)

This MIGHT make it a bit clearer  I find it is easier if you separate out all the three genes that are at work to get your head round it. 

Basically  as above Grey is a dominant factor that does not affect coat colour genes but if inherited in any way will turn all the hairs on that individual at varying speeds to white, there is currently no way to tell if a horse is homo or heterozygous for grey by looking at it and I am reliably told that any genetic test for it is a long way off yet. 

Being a dominant grey cannot be carried, it is there and visible or not there and as such if a horse is chestnut from a grey stallion, the grey is lost for good and has no further part to play in that family. (With the exception of course of Appaloosas where it can be hidden by the varnish/fading gene and other coat patterns!)  

Then you have to look to the Extension series which produce the only base coat colours in the horse, i.e. either Black or Chestnut. As in the above post. Chestnut is recessive and must have 2 chestnut genes to be a chestnut.

The Es are quite easy to work out on a stallion with a good number of progeny even if he has one grey gene. Ask has he ever produced a black, brown or bay foal from a chestnut mare? If he has then he must have at least 1 Black gene, then ask has he thrown chestnuts yes = He is a Black carrying Chestnut and no = He has 2 black genes and cannot throw a chestnut.   I use stallions here as mares do not usually have many offspring so are more difficult to say for sure.

You can also do this with a homozygous grey IF his owners record the colour the foals were born, which unfortunately they seldom do! 

Then you have to deal with the Agouti gene, this has no known effect on a chestnut coat but if present in the genes of a black horse it will turn some of the hairs in the coat to make a Bay, if a horse has the allele "At" then the t extension denotes  it is a Brown. So Bay and Brown are not technically base coat colours and also at until recently they could not tell them apart in tests. 

Agouti can be carried silently by chestnuts, I have 2 chestnuts and a bay genetically tested so far that all have two Agouti genes, so they are incapable of producing a black horse. But if a stallion has sired a black horse then you know both it and the dam either do not have Agouti or only have one Agouti each. 
But again with grey it has to sire a lot for you to be able to say if it sired a black, some foals destined to grey are born very dark almost black and some a born grey and sometimes it is VERY difficult to tell visually if a horse is black or brown if it doesn't have grey! 


Its really quite complicated as you have to consider all three series of genes to work out what you are likely to get in this relatively simple mating,  then horses being horses you will get the one that is  least likely and usually what you liked least!!!!!! 

If you really want a headache or more like a migraine then Appaloosa spotting patterns are your gene!

Testing can be done currently on both the E and A series genes, the cream gene, Tobiano,  Overo (lethal white), one of the Sabinos, silver dapple and very shortly Champagne and Brown. 

(I should say here, that there is a theory that there is a dominant black coat colour that overrides Agouti, but thats another story!)


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## Daisychain (21 May 2008)

Wow there is such knowledge! thanks everyone it is very interesting reading.


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## SirenaXVI (21 May 2008)

[ QUOTE ]
at our yard we have a 4yo strawberry roan sort of colour very pretty. mum was a skewbald father a grey. 

[/ QUOTE ]

The grey gene (modifier as JG said) is not connected to the Roan gene,  Dad was probably a roan with the greying gene, hence the foal being strawberry roan. Dad was also obviously only carrying one grey gene and not two.

My grey Anglo mare, was actually born chestnut, mum was a dark bay TB, dad grey arab who, I suspect, was a chestnut too.  She had two foals by a black stallion, one born dark bay and turned grey, the other born bay and stayed bay, this means she only has one grey gene, and is more than likely carrying the red (chestnut) and the agouti (bay), bay being dominant.

Edited because I am knackered and can't spell tonight!


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## cruiseline (22 May 2008)

Thanks for the help KarynK, I didn't want to get into the Agouti gene, as I knew I would mess it up.

Colour genetics fascinate me, I could talk and listen all day about them.

A question for KarynK.........

I have put this :-







To this







I know that the stallion has roaning, what is the likelyhood that the foal will get roaning. Also do you think I will get a spotty botty. Not long to wait now mare is at 334 days today  
	
	
		
		
	


	





Great thread.


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## Daisychain (22 May 2008)

If i wanted to avoid breeding another chesnut, i would have to make sure the stallion and his parents were all non red then! if this makes sense.


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## cruiseline (22 May 2008)

Exactly, If you have a chestnut mare, or a mare you know carries a recessive chestnut gene, then to avoid a 50% chance of getting a chestnut foal you would have to chose a stallion who is proven not to carry a recessive chestnut gene. 

One that comes to mind at the moment is Renkum Valentino, he can not produce a chestnut foal.

I am sure there are others, anyone know any more.


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## volatis (22 May 2008)

There are loads out there. My black mare carries chestnut but she is in foal to Samaii who is homozygous black, so we know at least the foal will not be chestnut (thats if the damn foal ever arrives!)
Sandro Hit cant sire a chestnut is another famous one that springs to mind


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## cruiseline (22 May 2008)

Volatis, that reminds me of a foal I once bred. I put a black show pony mare, with a little white star and 2 hind socks to a black show pony stallion with just a little white star. Out popped this bright chestnut foal with a big white blaze and stockings. I was shocked to say the least. The stallion owner even came down to have a look at our ORANGE baby. We did manage to trace back to where the foals genetic make-up had come from, as I was convinced a different stallion had been used, even though I knew it was a natural covering.


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## Daisychain (22 May 2008)

How funny lol!  thats the thing with breeding, you have all these ideals and they still come out completely different!


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## Daisychain (22 May 2008)

While were still at it, a piebald to a chestnut mare is there a higher percentage either way? Or is it 50/50 again! Thanks.  I am trying to avoid another ginger lol! i have had so many!!


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## cruiseline (23 May 2008)

Firstly, you can be guaranteed that your chestnut mare will pass on the recessive chestnut gene, you can not get away from that fact.

If the piebald stallion carries a recessive chestnut gene then yes you have a 50/50 chance it will be a chestnut foal.

Also if the stallion is not homozygous for the piebald gene (ie. carries 2, one from the mother and one from the father) you have a 50/50 chance that it will be a coloured foal too.

To avoid a chestnut foal you really have to find a stallion that does not carry a recessive chestnut gene, then you will have your 100% guarantee of a non orange baby.


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## Daisychain (23 May 2008)

Thanks Cruise, you have been very helpfull.


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## Shilasdair (23 May 2008)

My 3yo was from a grey stallion (Accondy) out of a chestnut mare...the foal was born chestnut with a greying gene so is now sort of dapply grey (she went through a chestnut roan phase first).
I don't know the genetic status of the parents....but no doubt some genetic genius will 
	
	
		
		
	


	




S


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