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Pearl

Hey, I have a hard time getting my head around that a Pearl/Cream horse must pass on either a Pearl or a Cream gene to it's foals. It seems to be something to do with Pearl being a cream mutation, but if they can test for Pearl, then isn't it different enough to Cream to have it's own genetics.... I think I'm just confusing myself! If I think of Pearl as being similar to At, thus Pearl should be written Cr with a little 'p' maybe? Because it's just another form of Cream?? Anyone know more about this to explain it better to me?! Cheers Danni

Heather Sun, 05/03/2009 - 19:06

oh boy lol i feel and old headache coming on :laugh1 ..its all coming back to me now.

Daylene Alford Sun, 05/03/2009 - 19:13

I've been doing some internet searching and can't seem to find any horse that is homozygous for pearl + has a cream gene or is homozygous for cream + pearl gene.

Very interesting.......

Daylene Alford Sun, 05/03/2009 - 19:20

[quote]Barlink gold rush?[/quote]

It appears he has one cream and one pearl.

Maigray Sun, 05/03/2009 - 19:49

Has any research on pearl been published? I simply can't recall.

Edited to add: I assume UCDavis is holding out for financial gain, but if Avian has it as well, then their advantage is lost, or will be. They should publish soon.

Fledgesflight Sun, 05/03/2009 - 20:01

I've searched- and can't find one foal who did get Pearl and Cream from one parent... Barlink Gold Rush is the perfect candidate for either one or neither (Cream/Pearl) passing on...seems the theory holds water and I'm a bit shocked!

Searched all of these
http://www.angelfire.com/mb/pterelas/di…" onclick="window.open(this.href);return false;

horsegen Sun, 05/03/2009 - 20:03

No, UC Davis has not published their pearl research. They should, of course. It's silly that they haven't. The reason has nothing to do with the research not being sound...it's more a, well, administrative thing.

For obvious reasons, I can't clear up this thread. I understand everyone's confusion and there is certainly some misinformation at work here. Let's just say that if two genes are very closely linked, or alleles of the same gene, as Carolyn Sheperd says, then one might see a phenomenon like this within a breed without there being an exact "rule" about it. For example, if two genes are very close together on a chromosome, then in order for a horse to pass them BOTH to an offspring, they'd have to both be on the same chromosome:

-------P-C-------- --> passed to offspring, so offspring gets P and C from same parent
-------p-c--------

Now, if pearl is floating around in the breed and it came from an ancestral source that was pearl, but NOT cream, that means that in order to have both on the same chromosome, a pearl/cream horse would have to have a recombination event between P and c to move them both to the same chromosome.

--------P-c--------
X
--------p-C--------
(Sorry, that X is refusing to be in the right place. It should be between the P's and C's!)

Obviously, if two things are very close together, the chances of this recombination event are very, very small. So most horses that have pearl and cream would have them on two different chromosomes, one from the dam and one from the sire. But that's not to say that it's impossible! So maybe the best thing I can say to clear up this discussion is that many things in genetics can be said to be "rules" when they aren't really. It's just that fate and ancestry have contrived to make one circumstance more likely than another.

I wish I could help more...just thought I'd chip in a thought that might help. I really wish the paper would come out, that's what I wish... :BH

Morgan Sun, 05/03/2009 - 20:08

have any cream pearls had tested foal with[i] neither[/i]?

horsegen Sun, 05/03/2009 - 20:10

Given the above hypothesis, that would be equally unlikely, since the same recombination event would have to happen to move both to the same chromosome (it's just that the p/c chromosome would be passed on rather than the P/C chromosome).

Morgan Sun, 05/03/2009 - 20:22

hmmm if that did happen you would end up with a line of, for all intents, true breeding white/cream colored horses :shock:

Danni Sun, 05/03/2009 - 20:43

[quote="horsegen"]No,Now, if pearl is floating around in the breed and it came from an ancestral source that was pearl, but NOT cream, that means that in order to have both on the same chromosome, a pearl/cream horse would have to have a recombination event between P and c to move them both to the same chromosome.

--------P-c--------
X
--------p-C--------
(Sorry, that X is refusing to be in the right place. It should be between the P's and C's!)

Obviously, if two things are very close together, the chances of this recombination event are very, very small. So most horses that have pearl and cream would have them on two different chromosomes, one from the dam and one from the sire. But that's not to say that it's impossible! So maybe the best thing I can say to clear up this discussion is that many things in genetics can be said to be "rules" when they aren't really. It's just that fate and ancestry have contrived to make one circumstance more likely than another.[/quote]

So with this in mind, if we do eventually get a foal from a pearl/cream that has neither or both, the theory still stands because it's just one of those very rare events??

horsegen Sun, 05/03/2009 - 20:46

[quote]hmmm if that did happen you would end up with a line of, for all intents, true breeding white/cream colored horses[/quote]

No, ONE of their chromosomes would have both, the other would have neither. So you still have a 50/50 shot of cream and pearl, it's just that you're either going to inherit both, or neither--not one or the other.

[quote]So with this in mind, if we do eventually get a foal from a pearl/cream that has neither or both, the theory still stands because it's just one of those very rare events??[/quote]

Theoretically, yes. If pearl/cream parent (which had one cream and one pearl parent) is bred to a non-pearl/non-cream and the foal is both pearl and cream, then the rare event must have happened.

Morgan Sun, 05/03/2009 - 20:58

[quote="horsegen"][quote]hmmm if that did happen you would end up with a line of, for all intents, true breeding white/cream colored horses[/quote]

No, ONE of their chromosomes would have both, the other would have neither. So you still have a 50/50 shot of cream and pearl, it's just that you're either going to inherit both, or neither--not one or the other.
[/quote]
sorry, wasnt expressing myself right, I knew that :BH :sad
actually I think I was thinking extremely long term if it did swap over at some point, you could then breed a horse (through inbreeding probably) that has both cream and pearl on BOTH chromosomes. all foals would be pearl and cream and hence a funky creamy color.
I know I'm being silly, but I have a cold, I'm allowed to think wierdly :lol: :bounce

accphotography Mon, 05/04/2009 - 02:16

Thank you Horsegen, yet again. I understand your predicament and it is INCREDIBLY frustrating. I even suspect I have an idea why it is tied up in administration... well, I have a suspicion. :lol:

How long has this been delayed?

I hope they get it out soon, this is information we really need. I'm actually incredibly frustrated that this is the first I've heard of this, and it seems it's largely true (in some ways, but not in others). I thank you for your idea. It helped me tremendously. I also find it very disappointing if the idea I have in my head is accurate. :sad

Since it is all still theory until someone publishes it, I'm not eating crow yet, but based on what has been said I will say I am prepared to. Albeit I don't think it's going to be 100% accurate as it was stated by Sheperd. Based on what I now suspect is the case, neither interpretation of her statements can be accurate.

Horsegen: Can we ask... how/why is Avian Biotech testing for pearl? Was Davis aware of this? I suspect there's not much you can say about it, but anything would help. :)