HGG Community Forums

Gotcha! Makes so much sense

I think sorrel and chestnut are a regional and discipline kinda thing. I (who rides western in the south) has never heard someone call a red horse chestnut.

@Blaze- That's funny I'm from the south too and have only ever used the term chestnut! I think it's mainly discipline-based though. I ride English, and the only person I know who uses the term sorrel breeds reining horses.

I always thought sorrel was a chestnut horse with white or black hairs scattered throughout their coat.

Maribo, my red mare has black hairs. She has sooty marbling on her shoulders that is black and sunfades and a Bend Or spot that is black and stays black.

What she said ^^

Except I didn't say that red horses don't produce black pigment because "agouti doesn't affect them." I said Red horse do not produce black pigment because they only have recessive extension and can only produce pheomelanin. Therefore, agouti - whether AA, aa, or Aa has no impact on their phenotype. *Because they don't produce eumelanin* and Agouti impacts the distribution of black hair.

And it's not semantics. It's genetics. We haven't mapped all of the equine genome. Technically, we don't even know if there are genes that work the way that flaxen, sooty, and pangare work in the game - we assume they do, because of what we observe in horses, but we haven't actually identified them. There's new modifiers being discovered all the time. I find it much more likely there are multiple modifiers or environmental factors that control shade than that some horses with recessive extension produce black hair even though they can't produce eumelanin.

This also meshes well with the observations that certain breeds are known for producing "extreme" colors - think how miniature horses and morgans (Merwin All A Breeze) is a great example. If you had advertised Merwin as a black stallion, because calling him "so red he looks black" was just semantics, you'd have a lot of disappointed mare owners.

Bend Or spots are not always black. They can be dark red, too. Because they come in a range, because they are concentrated pigment. Not all sites on the internet have accurate horse genetics information. EDIT - I found three or four sites with less than five minutes of googling that confirm a range, so not "Every thing on horse colour sites everywhere" refers to Bend Or sports as only black.

Since we don't know for certain what causes Bend Or spots, there's no answer as to why cream doesn't dilute them. But cream isn't a perfect dilution gene - when cream is paired with tobiano, there can be patches where the cream "turns off" and isn't expressed, resulting in a non-dilute patch. If you google "calico tobiano horse" you can see some examples of this. It's possible that whatever causes Bend Or spots to appear also impacts the presentation of cream.

So if you concede that whatever causes Bend Or Spots can impact the presentation of cream, then why do you not concede that both sooty and bend or can switch on black pigment in red horses? Because clearly, based on phenotype, that’s exactly what it does.

Because it's not creating chemicals that aren't being produced. It's turning off the suppressor of cream. It's not creating red pigment - the red pigment was already there. For sooty or another gene to create black spots, it would have to result in the production of pigment that is being turned off by the horse being recessive for extension.

The somatic mutations that allow bloody shoulder, etc. in grey are more analogous to the effect of cream/calico. Grey is a pigment disease that causes the pigment producing cells to overproduce and burnout. Where the grey is switched off, due to the somatic mutation, it causes the base color pigment to be produced normally. Once again, it's not causing the creation of new pigments. It's just not burning out the ones that already exist. Similarly, the somatic mutations I have seen are either causing white ticking or dark patches of the existing base coat color (i.e. dark brown on light brown).

And yes, the hairs may look black, but they are super-concentrated red pigment. The food dye in the bottle isn't black just because it looks black. It's red. You can call it black as a descriptor all you want, but it's still red.

It’s the same in dogs, paradox. A chocolate lab can’t have a black nose because they physically don’t have black pigments, only red (chocolate). Red is recessive to black, meaning it can’t have any black genes to be presented. Does that make sense?

LCorona, Chocolate labs don’t have a black-looking noses anyway. Not relevant.

Chateau, nothing in that says that a modifier (like sooty or whatever causes Bend Or Spots) can’t cause black pigment. It’s just talking about the unmodified bases of e or E. e, by itself, can only cause red pigmentation. Sure, I’m not arguing that. But clearly, the addition of a modifier *can.*

Find me a reference that says that the black-looking sooty hairs are actually red. Because otherwise, you’re just guessing off of partial information.

I won’t ever call the sooty marbling or bend or spot on my mare “dark red.” If I told you she had “dark red marbling” or a “dark red bend or spot” it would give you or anyone an entirely wrong picture of what she looks like. The hair is black. Or if someone had their chestnut had “dark red hairs in their coat” it’s entirely an entirely different picture than “black hairs in their coat.”

And we still have the problem of black-looking palominos. Cream easily and dramatically diluted red pigment, but, unless Homozygous, it doesn’t dilute black pigment much at all. Explain how, if these dark hairs are red, they do not get diluted by cream. Cream isn’t “switched off” because it has diluted any visible red hairs. Why doesn’t it dilute the black hairs?

Easy. They are indeed black.

Basically, by your logic, ee horses cannot have black pigment because they have no E.

But, if they were true, all bay horses should be Ee since they have both black and red pigment. But we know, courtesy of testing, that bay horses can be EE.

But where does the red pigment come from if they have no e? Agouti causes it by not allowing the production of black pigment on the body. Leaving the only other possible option: red.

Likewise, it should be completely possible for other modifiers to do the opposite.

And why does being a professional rabbit breeder make you any more qualified on equine colour genetics than me?

I have years *years* of research *and* discussion with other equine colour enthusiasts. Well before I even knew this game existed.

This doesn’t matter. I don’t want to argue. It makes no difference to me if your horse is red with black spots or not. Lol