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B gene?

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lillith
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B gene?
Horses are believed to be homozygous at the B locus that in dogs gives you liver skin pigment, so even though the hair in a chestnut is reddish the skin underneath is black. So are smut marks that black skin pigment overruling the chestnut hairs in small patches by a mutation in some way????
Ummmm? Read this on another forum and have never heard it before, from the same person who says that splash and sabino mutate into eachother at random so not taking it as gospel, just wondered if anyone had heared anything similar? Also stated was the ee horses cannot produce black pigment at all, I was interested to find out if 'sooty' marks on ee horses are very concentrated phaemelanin or actually eaumelanin (spl?).
Third Peppermint
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Re: B gene?

We had the writing about the B gene in my equine production class notes. Someone told me that horses don't have the whole liver vs. black, though. The notes listed which breeds it happened in, but I can't remember. I will say that the "light black" and "light bay" horses make me wonder if liver exists in some form, but I can't say I'm sure of the genetics behind that locus.

I think the notes said they had chocolate brown hair, and purplish black skin? I'll try to find what it said when I get home.

accphotography
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Re: B gene?

It's not true to my knowledge. I've not heard a single researcher (in horses) refer to it as even a possibility.

That person drives me crazy.

I personally believe sooty and Bend Ors are actually black pigment. It SHOULD be easy to find out but I've never heard of anyone trying.

IMAGE(http://i173.photobucket.com/albums/w65/accphotography/Misc/Sig.png) IMAGE(http://phrf.pitapata.com/uno2m5.png)

Dogrose
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Re: B gene?

In the past chestnut was thought to be on the B locus and be related to liver/chocolate in other species, probably due to it's simple recessive nature. Its now known not be, and I've read somewhere there is no mutation of the B locus in horses, at least not that has been recognised. Some very old books and papers link chestnut to the B locus, maybe thats where they got their info from.

[color=#804000][i]I bought me a horse twas called a grey mare
Grey mane and grey tail and green stripe on her back
Grey mane and grey tail and green stripe on her back
Weren't a hair upon her that was not coal black[/i][/color]

Monsterpony
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Re: B gene?

I agree with what has already posted. B is not a horse gene and hasn't been really thought about since extension was established.

.

nerd
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Re: B gene?

Don't know anything about the B locus, but in response to whether ee's are able to produce pheomelanin instead of just eumelanin, I'm pretty sure the answer would be in this paper:
Sponenberg DP, Ito S, Eng LA, Schwink K. "Pigment Types of Various Color Genotypes of Horses" Pigment Cell Research, 1988, Vol. 1, Iss. 6, p. 410-413
(which I don't have access to... does anyone else?)

Danni
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Re: B gene?

Horses are believed to be homozygous at the B locus that in dogs gives you liver skin pigment, so even though the hair in a chestnut is reddish the skin underneath is black.

I guess she says that because there ISN'T a mutation of B in horses, so she's just making the assumption that horses are the 'B' dominant form...??

B in dogs is definitely a sort of dilute I reckon, not as much as the identified dilute gene, but it turns both the skin and hair to that liver colour, eyes to yellow etc..

NZ Appaloosas
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Re: B gene?

I have that paper! (somewhere). Dr. S mailed it to me, and I was going to scan it and put it on here, but then I forgot...now where the h**l did I put it???

Diane

lillith
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Re: B gene?

ok thanks guys, I have asked (nicely) for the paper so I will see if she comes up with anything.

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