[prettyqtrs]

Have been wondering about this.....
Genetically what is a brown? How can you get it(from what and what color/s/)? If you did a coat color test on them what could the results come back as? Can they have a cream gene? Be homozygous black? Red factor status would be either Ee or E(if they are able to be homozygous black)? Their agouti status would be A or Aa right?

Thanks in advance!

[S.HorseWoman]

Agouti is the gene that restricts black and allows red to show through.

There are thought to be three forms of Agouti: A - normal bay (AA is homozygous bay), A+ - wild bay (black is more restricted and shows up less on the legs than a normal bay), and At - which is brown.

Technically there is also a, but that just means the horse does not carry Agouti in an active form so the horse would be black if it has at least one black gene.

Agouti can be hidden by chestnut because a chestnut horse has the genetic profile ee, which means double red. Agouti only affects black so it is not visible on chestnuts, but can be passed onto foals.

For a color test, if the horse is a "true" brown, it will show up either Aa or AA, which is either heterozygous or homozygous Agouti. They have not developed tests for the types, so Agouti just shows as Agouti.

You can get a brown horse if you have at least one Agouti gene I believe. Again, they have not done enough tests to really be completely certain how brown works so not 100% sure.

A brown can carry creme, and would probably appear to be a darker buckskin I think. A double dilute brown would probably resemble a perlino, or possibly a smoky cream. Again, they don't really have a set test to find out exactly what Agouti a horse has, so you just have to go by visual features.

And yes, they can be homozygous for black, just like a bay. A bay horse can be homozygous black as well, but those horses are the ones that tend to be really DARK bays.

Now there are "browns" that are actually blacks with what is called pangare, which is a gene that causes the muzzle, flanks, and underbelly to become brownish. That is not the same as "true" brown, but is instead a black horse with a modifier.

Hope that helped a little and was not too confusing .

[prettyqtrs]

Nope...that was good. Thanks for taking the time to explain all of that! See I'm pretty good with the single dilute colors and dd's and some more basic colors(sorrels, bays, blacks, ect)...but browns just haven't come up so haven't really learned much about their genetic *color* makeup. We breed QH's and have learned a lot with colors already...but as you know there's a lot to learn...and Im by far no expert at it yet. lol.

Thanks so much!

[S.HorseWoman]

No problem; color genetics is one of my favorite things to study . I am certainly no expert though!

Sorry the post was a bit rambling and not super organized; I was trying to think through things as I typed so it came out as a sort of "thought stream" instead of something a bit more logical in order .

[Painted_Spots]

hmm... and I always thought brown WAS black with the pangare gene? I thought the only difference between brown and black was the 'mealy' color around the nose, and sometimes flank and barrel?

[S.HorseWoman]

Originally Posted by Painted_Spots

hmm... and I always thought brown WAS black with the pangare gene? I thought the only difference between brown and black was the 'mealy' color around the nose, and sometimes flank and barrel?

That is what brown was originally thought to be. However, a university (for the life of me, I can't remember which one) did a bunch of tests on browns, trying to determine just that. A large number of them came back as genetically carrying Agouti, something a black horse can't do. A black horse with Agouti is technically a bay. So after some extensive testing, they proposed that there were two forms of "brown": black with pangare (which genetically tests as not having the Agouti gene) and "true" brown, which is a bay with the At gene (a form of Agouti) instead of the "normal" Agouti gene.

Here is a page with some good information on brown (they refer to it as seal brown, but is really the same thing I am talking about): http://www.ultimatehorsesite.com/colors/sealbrown.html