grey mare-color genetics?

[alto]

But now imagine that there are grey modifiers - separate genes, linked genes or if you really wanna get crazy, a mix of both - & those Egyptian Arabs have more of those modifiers (especially the linked ones) so that a parent that is G/g does not actually produce 50% G foals & 50% g foals, but instead almost every foal is grey such that 85% of progeny are now grey …
would you not then describe this as a “stronger grey” :lol:

(ie non-mendelian inheritance cause it’s pretty much a given that Mendel “helped” his data)

Coincidentally FP’s dam is heterozygous grey, bred to same buckskin stallion: foals are 2 grey-palomino colts, 2 grey-buckskin fillies, 1 grey-chestnut colt, 1 bay colt; bred to bay stallion: 1 grey-bay colt … easy to see why someone might consider this mare to be a “strong grey”.
So while the academic chance of her next foal being grey is 50% (assume she’s again bred to a non-grey stallion), my empirical data suggests that foal will be grey :sigh:

[SaturdayNightLive]

[QUOTE=alto;6302780]

Coincidentally FP’s dam is heterozygous grey, bred to same buckskin stallion: foals are 2 grey-palomino colts, 2 grey-buckskin fillies, 1 grey-chestnut colt, 1 bay colt; bred to bay stallion: 1 grey-bay colt … easy to see why someone might consider this mare to be a “strong grey”.
So while the academic chance of her next foal being grey is 50% (assume she’s again bred to a non-grey stallion), my empirical data suggests that foal will be grey :sigh:[/QUOTE]

That’s not right either. You’re confusing a 50/50 chance of grey with the idea that 50% of the foals will be grey. You have a 50/50 chance of the heterozygous mare producing a grey foal each time. The color of the previous foal has no bearing on whether or not the grey allele will be inherited. Each foal has the same 50/50 chance. If you flip a coin 100 times, chances are that you aren’t going to get heads exactly 50% of the time, but that doesn’t change the fact that with each coin flip you have a 50/50 chance of getting heads.

[JB]

I don’t think we should make fun of rmh_rider, as she’s obviously got a history of having been told incorrect information, or has made up her mind based on visuals which can be a very bad thing to do when it comes to color genetics.

rmh, if you look at the UC Davis genetics site - among the leading equine genetics researchers - you will see this
[I]
Gray results are reported as:

N/N No copies of the gray gene. Horse will not turn gray.
N/G One copy of the gray gene. Horse will turn gray and approximately 50% of offspring will be gray.
G/G Two copies of the gray gene. Horse will turn gray and all offspring will be gray.
[/I]

It really is as simple as that.

SNL is right about percentages over a population. 2, 3, even 10, 20 foals may seem like it tells the whole story, but it’s not statistically significant. Remember, roughly 50% of a population will be boys vs girls, but Equine Repro at one point had 49 colts in a row STILL not statistically significant enough.

People like to say a stallion must be EE homozygous black because he had 30 foals out of chestnut mares and none were chestnut. Well, the odds are increasing that he’s EE, but 30 isn’t enough to definitively state that.

alto, there ARE some genes that are linked, which skews the 50/50 ratio. Extension and Tobiano are linked, and usually the T is linked to the e. Over time, in a given population, that means there are roughly a 50/50 mix of Tobianos with a fairly equal distribution between the red-based and black-based colors (assuming 1 horse is Tt and the other is tt).

BUT, in certainly lines, the Samber line being a well-known one, the link with T is with E. So, that same Tt bred to tt where the T and E are together, still produces roughly 50% Tobis, but NONE of them will be red-based, all of them will be black-based.

I think gray has been around long enough that any such linkage would have been discovered, so it’s pretty safe to say something similar doesn’t exist

[Daventry]

@SaturdayNightLive;6302858

The color of the previous foal has no bearing on whether or not the grey allele will be inherited. Each foal has the same 50/50 chance. If you flip a coin 100 times, chances are that you aren’t going to get heads exactly 50% of the time, but that doesn’t change the fact that with each coin flip you have a 50/50 chance of getting heads.

Thank you!

Our 23 year old heterozygous grey Welsh Pony stallion has had approximately 75% grey foals over the years. It has nothing to do with the fact that the Welsh Pony population tends to have more greys than other breeds or that there is some strain of a stronger grey gene in there. It solely has to do with the fact that there is a 50/50 chance of each and every foal turning grey. Period. :yes:

[JB]

But Daventry, how many gray mares did he cover? His Gg mixed with Gg gives a 75% chance, and any GG mares would have made it 100%.

So even with a Gg stallion, given the number of foals produced over a lifetime, especially in a breed where gray IS more common therefore the number of gray mares is likely larger, I’d fully expect more than 50% grays in his kids

[Ibehorsepoor]

I bred my grey mare to a grey stallion on purpose. I got a lovely bay colt…lol… both my mares parents were grey.

the Stallion had to have a grey parent… I was so sure I would get a grey… nope, and before anyone tells me it could happen… he has not a grey hair around his eyes or anywhere…
:eek:

[JB]

got a picture? Sometimes the tell-tale white hairs are missing. But the shade of the foal coat is a more reliable (though not foolproof) indicator.

If he’s a bay like an adult, meaning black legs, they he’s likely going to gray. But if he’s got the tan/silver legs of a foal bay coat, it’s highly unlikely he’s going to gray

[DLee]

Am I correct that even if both parents of a horse are grey that horse might still not be homozygous grey?

[Simkie]

@DLee;6303231

Am I correct that even if both parents of a horse are grey that horse might still not be homozygous grey?

Yup.

Case in point: my filly.

Pedigree: http://www.pedigreequery.com/seven+springs4

Photos: http://pets.webshots.com/album/582505855rjhYQq

Sire and dam are both grey, and both heterozygous. Filly had a 1 in four chance in coming out not-grey.

She is grey, so she had a one in three chance at being homozygous grey. Because I am a giant nerd and I like these things, I had her tested. She is heterozygous.

The only way you are GUARANTEED a homozygous grey is if both parents are homozygous for grey.

If one parent is homozygous and one is heterozygous, you have a 50/50 shot of homozygous vs heterozygous.

[DLee]

Okay thanks! I am expecting a C.Quito foal any day, my mare is bay and he is grey, I think both of his parents are grey, but I don’t think he is homozygous, kind of hoping for a grey. :yes:

And lovely filly btw!

[SmartAlex]

Anecdote: Grey Foals…be careful what you wish for…

My mother wanted a grey very badly. She bred our bay ASB mare to a homozygous grey Arab stallion. The stallion owner guaranteed it. Said he didn’t care if the mare was pink, we would get a grey foal…

We got twins. Two grey foals. :yes:

They both survived, but they ended up being rather small, considerably smaller than either parent. And you couldn’t get two more different siblings if you tried. They were totally unalike in type and temperment. But they were both grey.

[JB]

[QUOTE=DLee;6303253]
Okay thanks! I am expecting a C.Quito foal any day, my mare is bay and he is grey, I think both of his parents are grey, but I don’t think he is homozygous, kind of hoping for a grey. :yes:

And lovely filly btw![/QUOTE]

In looking at his page (oh my, he’s something, LOVE his pony-like head!!) I think the 6/15/10 colt is not gray, which points to C being Gg.

[Simkie]

@JB;6303285

In looking at his page (oh my, he’s something, LOVE his pony-like head!!) I think the 6/15/10 colt is not gray, which points to C being Gg.

Yep, I was thinking the same thing!

DLee, looks like it’s a 50/50 shot for grey for you

[Daventry]

@JB;6303128

But Daventry, how many gray mares did he cover? His Gg mixed with Gg gives a 75% chance, and any GG mares would have made it 100%.

So even with a Gg stallion, given the number of foals produced over a lifetime, especially in a breed where gray IS more common therefore the number of gray mares is likely larger, I’d fully expect more than 50% grays in his kids

Oh no, I totally get that. Obviously if our grey stallion was bred to grey mares, the likelihood of grey increases quite a bit. Just pointing out that his percentage of grey foals has nothing to do with JUST him being able to pass along some 75% chance of grey or some made up number just because there are a lot of greys in the breed, as rmh_rider is suggesting. If she did her research and understood that breeding a grey Arab to a grey Arab could result in at least a 75% chance of grey, she would start understanding that it has nothing to do with the breed itself…and simply due to genetics.

[DLee]

[QUOTE=JB;6303285]
In looking at his page (oh my, he’s something, LOVE his pony-like head!!) I think the 6/15/10 colt is not gray, which points to C being Gg.[/QUOTE]

Thank you, I’m stressed/excited!

[JB]

[QUOTE=Daventry;6303293]
Oh no, I totally get that. Obviously if our grey stallion was bred to grey mares, the likelihood of grey increases quite a bit. Just pointing out that his percentage of grey foals has nothing to do with JUST him being able to pass along some 75% chance of grey or some made up number just because there are a lot of greys in the breed, as rmh_rider is suggesting. If she did her research and understood that breeding a grey Arab to a grey Arab could result in at least a 75% chance of grey, she would start understanding that it has nothing to do with the breed itself…and simply due to genetics. ;)[/QUOTE]

:yes::yes::yes:

[mikali]

Well, I have my fingers firmly crossed for my 25% non-grey, and would happily take any extra wishes that you might offer up to the genetic gods for me. Sire is GgEEaa and the dam is GgEeaa - so I know I am getting black… Mare is at day 319 with her second foal, so I’ll let you all know the results when the little one decides to arrive.

And as to the speed of base colour coat change to grey: My small experience has the 2010 chestnut/grey colt being the fastest to turn. The 1996 bay/grey gelding (now fleabitten), and the 2009 bay/grey, 2003 black/grey mares (fleabitten) are more of a medium speed to turn. The slowest is the 2006 black/grey gelding. All of them are heterozygous greys.

[Bayhawk]

[QUOTE=Ibehorsepoor!;6303209]
I bred my grey mare to a grey stallion on purpose. I got a lovely bay colt…lol… both my mares parents were grey.

the Stallion had to have a grey parent… I was so sure I would get a grey… nope, and before anyone tells me it could happen… he has not a grey hair around his eyes or anywhere…
:eek:[/QUOTE]

I have had this happen on numerous occassions. I’ve bred gray to gray for 3 full siblings. 2 were bay and the one was gray.

The Holsteiner stallion full brothers Cathalido and Cormint are examples also. They are by Calido / Carthago…both parents gray , yet Cathalido and Cormint are both dark bay.

[Wordplay1832]

Thanks for all the input guys! I do have a biology/genetics background but all I could find online for it was super dependent on base color and not simply the homozygous/heterozygous etc. and whether grey was dominant or not.

Haven’t decided for sure if I’m breeding the mare or not this year. She’s been having some issues that may retire her and I need to figure out what they are for sure and if it was an acute injury or something that I would not want to pass on and not breed. Or-best case scenario it’s something easy to fix that means she can compete a few more years before breeding, or give her a year off to make the baby and feel better and then start her back into work. But that’s a completely different topic entirely and one that I have basically zero answers about yet.

[JB]

[QUOTE=mikali;6303713]
And as to the speed of base colour coat change to grey: My small experience has the 2010 chestnut/grey colt being the fastest to turn. The 1996 bay/grey gelding (now fleabitten), and the 2009 bay/grey, 2003 black/grey mares (fleabitten) are more of a medium speed to turn. The slowest is the 2006 black/grey gelding. All of them are heterozygous greys.[/QUOTE]

That’s interesting. I will do some asking around and see if there is any known correlation in that, or if you were just “special”