the cream gene

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the cream gene

Postby LittleDove » 20 Jul 2012, 07:20

Hi, I'm hoping someone can explain a little more about the cream gene to me, particularly with reference to cream legbars. I've only recently discovered that what I thought were cream legbars, aren't because their neck hackles are gold and should be cream, so have been trying to find out more about this.

I keep reading that the cream gene is recessive, and here's where I am confused, (not hard to confuse me, I have only a very slender grasp on very basic genetics!)
If I understand a recessive gene correctly, then it requires 2 copies to express? If it expresses partly with 1 copy then it's incompletely dominant rather than recessive? Do I have that right?
Working on the assumption that I have that right, then why do some 'cream' legbars have bright gold neck hackles, and some have much paler yellow, but still not the required cream? Until I read the cream gene was recessive I thought that the gold hackled ones had no copies and the paler necked ones had one copy.

I know that in horses the cream gene can dilute chestunt to palamino if one copy is present, and to cremello if 2 copies are present, and looking at pictures of incorrectly coloured clbs, it seems that the same thing happens with chickens, but I can't make that tally with the gene in chickens being recessive.

Can anyone help me out by explaining it to me in simple terms, please [-o<
LittleDove
 
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Re: the cream gene

Postby Henwife » 20 Jul 2012, 13:06

My grasp of genetics is zilch, but my knowledge of True Cream Legbars is rather better. The first auto-sexing legbar was the Gold Legbar which involved several generations of breeding from a foundation of Brown Leghorn male to Barred Plymouth Rock female. Rather obviously, this has gold hackles (amongst other things) and lays white or cream eggs. When these were put to white Araucanas (and at this point I have no detail at all) they managed to keep the autosexing and get green or blue eggs. So far, so good. The Silver legbar, thought to be extinct, was a sport of the gold legbar.
When poultry keeping regained popularity, and domestic incubators the 'thing to have', it was quickly realised that an auto-sexing pure breed which laid premium coloured eggs was going to be a winner. In order to increase the number available either for sale as birds or for hatching eggs, some people crossed them back with Brown Leghorns to increase egg numbers or possibly to improve leg colour. Bad move; not only does this produce rather 'brown' birds, but they don't always lay green/blue eggs. These birds & eggs flooded the market, weren't always autosexing, weren't the correct colour, and often laid white eggs. You need to ask fairly searching questions about any eggs you buy in and if possible collect so you can see the parent birds.
I have a couple of bantam pullets that look like poor CLBs and lay green eggs. Papa is a white araucana x white leghorn, and Mama is a brown leghorn bantam. Pretty little garden layers, but if I entered them in an auction as CLB bantams, they'd sell well to some unsuspecting buyer.
Guinea fowl & a lot of surplus poultry equipment.
Henwife
Dutch Bantam Cockerel
Dutch Bantam Cockerel
 
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Re: the cream gene

Postby LittleDove » 20 Jul 2012, 17:26

hi henwife, thank you for the reply. I've already researched the history of the legbar and its colours, but not yet found anywhere that answers my question about the cream gene.
Thanks anyway :)
LittleDove
 
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Re: the cream gene

Postby Em » 20 Jul 2012, 20:32

Hopefully this site will help, I'm not very good with genetics but for cream legbars to be correct they need 2 copies of the Ig gene(inhibitor of gold), I have no idea if this gene is recessive or not but none of the gold hackled birds are technically cream legbars or do they have any Ig gene's.
https://sites.google.com/site/creamlegb ... ne/gallery
Em
Em
 
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Re: the cream gene

Postby LittleDove » 20 Jul 2012, 20:39

Thanks for the link, the pictures are very helpful.
I assumed the birds with very gold (almost welsummer colour) hackles have no copies. It's whether the ones with the paler more yellow gold have one copy that's confusing me. :scratch:
LittleDove
 
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Re: the cream gene

Postby Henwife » 21 Jul 2012, 06:42

I may no longer breed them Em, but what an excellent website that link gives.
Guinea fowl & a lot of surplus poultry equipment.
Henwife
Dutch Bantam Cockerel
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Re: the cream gene

Postby Em » 21 Jul 2012, 07:41

I have no idea re whether the paler gold ones have one copy of the Ig gene or not, never thought of it myself, just avoided them as there is no point in breeding from anything that doesn't carry 2 of the gene's. I have always thought that anything gold immaterial of whether it is pale gold or darker gold doesn't have any copies of the Ig gene but my genetics knowledge isn't great. My advice would be to avoid anything gold like the plague!
Yes HW, that is Bonnie's website, it's very good and informative. She has done very well with them and it makes me pleased that there are now quite a few others out there breeding good birds, it somehow lessens my burden for having given mine up
Em
Em
 
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