Questions about Greys genetically

[shoeboxstables]

Hi Everyone,

I was thinking this morning, and after mulling it over I'm more confused than when I started! I'm sure I could look it up somewhere, but usually asking you guys seems to work even better!

Ok. Grey. How does it work? I've been thinking about it, and I can't see how it is a normal 'color'. Is is more like roaning? I understand that color is controlled by multiple alles, but does grey have one itself? It obviously cannot be a regualr 'color' in that what base color would a homozygeous grey be? Is it technically a 'marking' then? I can't see what it would share with, unless it was just a sort of attachment on a normal color. Can roans be greys also? Ha- ok- could a blue roan pintaloosa with four socks, and 2 colored mane/tail grey out? (I know I just tossed in a ton of genes). And how is it that it is dominent over everything- right down to markings like distal spots? That would lead me to believe that it is like a disease that clings to and masks everything color-oriented (hehe sounds evil!). And why is it progressive?

Sorry- lots of questions- but I'm baffled! Anyone know?

:

(PS- when I say regualr color- I mean like Chestnut)

 

[hobbyhorse23]

You've got a pretty good grip on how it works already from the sound of things. Grey isn't a marking or color gene, rather it's a modifier gene- it "overwrites" every other color because (if I recall correctly) it either causes the pigment to stop being produced in the hair shaft or in any case effectively bleaches it out over time.

Gray can't come out of nowhere. If neither parent is gray, you have zero chance of a gray offspring. If they do have a gray parent, that parent has a 50% chance of passing it on to any given offspring. The gene is either "On" or "Off." Well, more accurately it's "There" or "Not There." If the horse gets a copy of the gray gene from the gray parent, then they will gray out as well. If they don't get a copy then they don't have it, period, just like a horse that has no grays in their background at all. They won't turn gray themselves and they won't ever produce a gray without being crossed to one. You can certainly get a homozygous gray genetically speaking, but I'm not sure what it would look like except perhaps a very fast graying horse! LOL

So yes, a roan can be gray just as any color can. A roan has something genetic (don't ask me what!) that causes them to have a mix of white hairs in their coat FROM BIRTH everywhere but the points. That's what gives them that funny pink or blue color. A graying horse bleaches all the hair, everywhere, in a certain pattern that may vary in intensity and duration from horse to horse.

Leia

Edited to clarify: Roan horses have a mix of perfectly normal colored hairs and pure white hairs, all the time. Graying effects each hair individually and turns them all white in the end regardless of what color that hair started. Clearer?

 

[Arion Mgmt]

I am assuming many things with your question, but I will try to answer the best way I can. First, I assume you are only talking about true grey and not silver dapple gray and that you know there is dappling in true greys that is the same as dappling in silver gray, but dappling is a separate modifier gene as well and not necessary for either color, and dappling usually is seen at some point in the greying process of both Greys and Silver Dapple Grays. Second I assume you are not talking about the varnishing of appaloosa's, it is not the same gene as Grey or Roan. Grey, Roan, and Varnish are all different modifier genes of base colors.

Grey is a gene and does have its own allele, it is a color modifier, not a base color gene, but all things involving life have genes and variants of those genes are called alleles. So what you want to visualize is a very very long street with homes on both sides with addresses, each address signifies a place where a gene is located, and each occupant of the addresses change, signifying alleles, occupants change, however there are only a certain number of occupants that can switch out at certain addresses. And sometimes there are no occupants, this is when a horse does not show greying, it does not have the allele.

Grey is signified as G^G

Grey is dominant and progressive and homozygosity has been shown NOT to affect the speed of the progression or the amount of greying, the speed also varies from horse to horse and breed to breed. If a horse has the Grey gene it WILL white out to some degree no matter the base color, and will usually maintain its skin pigment, not go pink. there are two main types of greying patterns. One type of grey all the hair will go all white, another only the body goes white the mane and tail stay darker and will never go totally white, but with both the skin usually stays pigmented. Also the grey horses that go white due to greying and age are NOT true White horses, those are all white color and pink skin and DARK eyes, and ARE NOT Cremellos, creme, pink skin and blue eyes.

Progressive genes only mean that the full affect of the gene is experienced over time, it is not expressed totally from the beginning, Appaloosa is a progressive color as well, including the modifiers of the appaloosa coloration.

Grey horses usually start out when a foal with white hairs around the eyes only. The head and legs are usually involved in the whitening first, versus roan and varnish that involves the body.

You can have a pintaloosa with Roan and Grey, but that would be unbeleivably rare to have a horse with all three genes, they would have the varnish modifier, Roan, and Grey, they are all different genes. The only way you would know if the horse had the grey gene is if the legs and head are involved early in age, bcause the varnish and roan do not involve the legs or head.

Also Flea-bitten Grey is a variant of Grey. Also sometimes Greys will have primitive markings like a dun, especially while young, but it is NOT the dun gene, it is seen breeds that do not have the Dun gene, Example is the Arabians, the reason is not known but it is transitional and usually does not stay. This does not mean there cannot be a true Dun- Grey.

Also many true Grey horses develop melanomas on the skin as they age.

John Eberth

 

[targetsmom]

I think a lot of us have been (or still are) confused about grey horses. I know that most of the grays I knew before I got into minis were Arabs and I just knew they were born "dark' (usually bay or chesnut) and turned gray over time. What I never considered was the vast array of colors that minis came in so that the original color of grey minis could be almost anything! Our "grey" mare is a case in point. She is actually a grey frame overo pinto, but she looks solid grey at this point. We got her registered as a Pinto based on a baby picture her breeder kindly suppled. We had her tested and she is LW0+. At that time we never thought to see what OTHER genes she was hiding, but we think now that she was a silver bay pinto at birth, so we will get her tested for the silver gene and a few more things. Her sire is Cross Country Call Me Awesome (bay frame overo) and her dam is Blue Boy bred (obviously grey), so silver bay genes are possible. We breed pintos, so the possibility of producing a silver bay frame overo pinto is exciting. On the other hand, we would be quite happy with a solid grey that looks, acts, and moves just like our mare.

 

[Arion Mgmt]

Targetsmom, are you refering to your mare that is GREY overo as a silver?? You do not need to test the mare for silver if neither parent is carrying the silver gene, the silver is different than grey.

Some people refer to the typical color seen in the Mniature of silver as silver dapple gray not grey, when in actuality there is a color that is easily confused with the silver gene. It is called in equine color books as sooty dapped palomino. Most of our silver dappled horses we have and refer to are technically light chocolate silvers.

Then there is silver bay which is technically right now called red silver. Silver chestnuts I have seen have a slight shade of silver on the legs and a slight shade of silver in the manes and tails, the reason is the lack of the Agouti gene to darken the points, because a chestnut does not have the black allele to interact with the Agouti. Unless the chestnuts are carrying the Agouti, which a red can and not show it, there is a test for the Agouti to find out. Other silver variants seen are, blue silver seen in Fresians(and its not like a blue roan color at all), dark chocolate silver, black silver, yellow silver (commonly called silver buckskins), then there is silver grullo.

John

 

[targetsmom]

See, I said it was confusing! No, the mare is grey, born darker and turned grey as a weanling. Her dam was grey and her granddam was grey, but I don't know what they were before they turned grey. I think my mare might ALSO be carrying the silver gene because she turned grey so early. I learned on this forum that grey horses that also carry the silver gene tend to grey out faster than others. I believe someone said that Blue Boy carried the silver gene, which might be where she got it from (through the maternal - grey - side). In her foal photo my mare does have a light mane and tail and some people on the forum said she looked silver bay.

Here she is now:

And as a foal:

 

[rabbitsfizz]

You can see the face marking clearly on her baby picture- and of course you have had her tested for LWO anyway.

She does look Silver Bay in that picture and it would be well worth testing her for Agouti and Silver so you know.

Unfortunately all her foals will have a 50% chance of going Grey.

As far as is known Silver has no effect on Chestnut and, although I have heard of Silver Bay being referred to as Red Silver it is not a common thing and very misleading- as are all the phenotypical descriptions such as Chocolate Silver et al.

I think it is better to stick to the base colour- ie Bay/Buckskin etc + Silver- some Silver Blacks show no apples at all- I have two, and I am coming to the conclusion that "dapple" is a modifier similar to "sooty" so really should not be used to describe a colour

 

[targetsmom]

Now, what do you mean "unfortunately"? I never understood how miniature breeders want Arab-looking minis but they don't like the color grey! We happen to like the color, although of course Pinto would be even better!

We do plan to get her tested for silver and Agouti, but of course, those tests don't have the same significance that the LWO did. Those are just "nice to know".

 

[rabbitsfizz]

Well, for a start Arab breeders are not breeding LWO!!

No, seriously, I bred Arabs for years but never had a Grey- well, one, Welsh X mare but that is all- they are nightmares to keep clean I was SO relieved to get Amira and Ayisha who were both Sabino Bays !!

I have never seen Arabs as Grey so "arab" to me does not mean Grey.

I am not a lover of grey or roan, for that matter as they alter so much of the base colour.

Each to there own though, and a good horse cannot be a bad colour/pattern/sex, I always say.

 

[shane]

JUST THOUGHT ID SHARE a picture of my stallion twinkletoes who is also grey, and i am so glad i got this picture off a friend who had it by chance

he was already grey by the time id bought him at the age of just under two, hes the stallion in my avatar

this is the foal above as a two year old

 

[Minimor]

If you're breeding with the intention of selling the foals I think you'll find buyers are more reluctant to buy pinto foals that may grey out. Anyone breeding for color--pinto, appaloosa--tends to shy away from any horse that may have the grey gene (and it can take awhile to show up in some horses, so even if the foal doesn't look like it's turning grey, some people still won't buy it if it's off a grey parent)--that's why you will hear so many Mini people saying "unfortunately there's a 50% chance any offspring will turn grey".

If you're breeding for yourself and you like grey then there's nothing unfortunate about the 50% chance of greying. That is a very nice mare you have!

 

[shoeboxstables]

Thanks everyone- this has really helped a lot! We have 5 minis- 2 greys, 2 grullos, and a black- so we have a herd of varying shades of black and white!

: Greys have always confused me- but this has really helped a lot! That is a beautiful mare you have targetsmom, and twikletoes is just too cute!

:

 

[Latika]

I have seen a few Homozygous grey stallions, they are born solid & grey out just same as all greys, their base colour is not homozygous only the greying out gene, so foal is still born any base colour, and greys out.

 

[ckmini]

So what about colors like "Grey Roan" how does that work? Is that a red roan with grey? I have a stallion who is registered as Grey Roan and as you can see he was quite rose-colored as a baby

But now he looks much more typical of a grey horse, and has lost his pink color.

 

[Abby]

I have two greys, one was born bay and has started greying out. And the other is from a silver bay mare and grey sire.

http://img.photobucket.com/albums/v207/Abb...5/Horsepics.jpg

She was born this way and has spots on her tummy too. Nope no appy anywhere, so how did she start grey?

Lee

P.S. I love her color, she will look stunning driving I think.

 

[rabbitsfizz]

Silver often affects Grey this way- all the greying out seems to have happened before or soon after birth.

H/Z Grey means the same as all other affecting genes- all offspring will inherit Grey, whatever colour they are born, which at least takes the guesswork out of it, even if it is a bit disappointing when you start off with a loud Silver Bay Frame Pintaloosa and end up with a white horse!!

Grey Roan can mean two things but usually means that the horse was born solid (Chestnut/ Bay/ Black) and when it started to Grey out the owner thought it was Roan.

A Grey horse can have Roan, but the head Greying out frost is a dead giveaway- if the horse truly has Roan the head and legs will stay longer.

 

[wpsellwood]

So let me just get this straight for myself. There is no way you can have a grey foal unless one of the parents are grey?? Correct?

 

[kaykay]

correct

 

[Field-of-Dreams]

Now, what do you mean "unfortunately"? I never understood how miniature breeders want Arab-looking minis but they don't like the color grey! We happen to like the color, although of course Pinto would be even better!

Grey "kills" app and pinto patterns, so you don't see them unless the horse is clipped closely. I would love to have a grey mare, but wouldn't want a grey stallion. I LIKE my darker colors!

Plus, 85% af all grey horses will develope melanoma by the time they are 15. My Arab had it. Most of the time it's just unsightly, but sometimes it can kill them.

Lucy

PS- your mare is GORGEOUS!!

 

[Ashley]

Well I guess we have a odd gray as she is over 17 and dont have anything wrong with her. You would never guess her age by seeing her, even in her scruffy coat she has going on.