Understanding egg color genetics

nicalandia

Free Ranging
12 Years
Jul 16, 2009
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One of those really interesting things to read about is that Punnett - meaning the guy who showed how to use "Punnett" squares - worked with blue egg layers. I had a lot of fun a few years ago reading where he documented that blue egg is a dominant trait and the steps he took to develop true breeding blue egg layers.
He sourced some chilean stock that were pretty much mongrels.. cream Legbars get their blue eggshell gene from them

The chinese version of the blue eggshell is allelic to the chilean Oocyan mutation so you cant combine both gene to get a deeper blue color.

We can confirm the sex linked nature of some brown egg shell genes with the user gide of some production type strain where Brown egg males mated to white leghorn type females produce darker shade eggs than the reciprocal cross
 

DarJones

Songster
Jan 24, 2021
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The chinese blue oocyanin gene is not just allelic, it is only one step on the chromosome away from the south American version and the best I recall is identical otherwise. In other words, the same virus caused a near identical mutation on two separate occasions.

This may sound unusual, but it turns out that it happens far more often than we would imagine. Chimpanzees carry about 100 copies of an extinct virus. The virus must have repeatedly infected chimpanzees over a few thousand years in order to be incorporated into the genome that many times. It is also worth noting that humans carry virus genes in our DNA for similar reasons.
 

nicalandia

Free Ranging
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Jul 16, 2009
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The chinese blue oocyanin gene is not just allelic, it is only one step on the chromosome away from the south American version and the best I recall is identical otherwise. In other words, the same virus caused a near identical mutation on two separate occasions.
Yes, they are nearly identical so one should not expect that crossing a homozygous Chilean Oocyan with the Chinese mutation type would cause an additive effect
 

NatJ

Crossing the Road
5 Years
Mar 20, 2017
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Yes, they are nearly identical so one should not expect that crossing a homozygous Chilean Oocyan with the Chinese mutation type would cause an additive effect
Do they both make the same shade of blue eggs?

It sounds like the two alleles may have no practical difference for most people, but I am finding it quite interesting that almost the same mutation happened twice.
 

DarJones

Songster
Jan 24, 2021
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To the best of my knowledge, the blue color is the same between the asian and south american variants of oocyanin. It is interesting that larger eggs tend to be slightly lighter blue and smaller eggs are often more intense blue. There is also an effect where pullets just beginning to lay produce smaller eggs with more intense blue shells but as they grow older and the eggs get larger the color becomes less intense. Having one copy of the oocyanin gene seems to produce eggs with slightly less intense blue color. The difference is so slight I have to arrange the eggs in order from least to most blue appearance to figure out which hens are likely homozygous and which are heterozygous.
 

AmeliaBedelia

Songster
Jan 23, 2021
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I have about 30 young birds of varying ages with a few due to start laying within the month and others that are nearly 3 months old. I am putting 50 to 60 eggs per week in the incubator. The number of eggs should increase as spring laying peak hits over the next few weeks. I will try to hatch at least 500 eggs this year to have an abundance for selection. With a bit of luck, I will wind up with about 50 Silver Laced Wyandotte colored birds that lay varying shades of blue eggs.
Is there a thread or somewhere that you've documented some of this? I'd love to see your current birds, as well as the "in between" stages of breeding.
 
Dec 1, 2020
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Western Washington
This just blew my mind right out of my head.🤯

So helpful. I was sold a Cream Legbar/Cuckoo Maran "olive egger". She's due to start laying any day now. Cant wait to see what happens.

I also have a normal Cream Legbar and a maran rooster. and im hatching EE/OE eggs right now. This was sooooooo helpful as I could not for the life of me try and figure out what was gonna hatch!😂
 

ALWAZL8

Chirping
Apr 26, 2019
13
35
54
Monroe, LA
I'm new to chicken genetics/breeding and just read in a thread on here last night that I could've known that my first-generation olive egger pullet (from a BCM roo x blue Ameracauna hen) would lay brown eggs instead of olive, based on her comb (single like her dad's). Mind blown! If I were to breed her for olive eggs in her chicks, a) is that possible? and b) if so, what roo should I breed her to? I have her dad, a BCM, as well as a fibro egger roo from a breeder - supposed blue egg line and he does have a pea-ish comb and no wattles and also a splash olive egger roo from the same breeder, who judging by the comb info is probably brown egg gene dominant.

My current flocks consists of the following breed of hens:
Buff Orpingtons
Barred Rock
Delaware
Easter Eggers (blue eggs)
CCLB
Olive Eggers (both lay brown)
French blue copper marans
Black copper marans
ISA browns
Red sex link
Blue australorps
Production red
Olive Eggers (these do lay olive/khaki eggs)
Blue Ameracauna
Welsummers

Please help me learn!
 

NatJ

Crossing the Road
5 Years
Mar 20, 2017
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USA
If I were to breed her for olive eggs in her chicks, a) is that possible?
Yes, if the chicks inherit the blue egg gene from their father.

and b) if so, what roo should I breed her to? I have her dad, a BCM, as well as a fibro egger roo from a breeder - supposed blue egg line and he does have a pea-ish comb and no wattles and also a splash olive egger roo from the same breeder, who judging by the comb info is probably brown egg gene dominant.
You need one that has the blue egg gene, so it sounds like the fibro egger is your best bet.

I'm new to chicken genetics/breeding and just read in a thread on here last night that I could've known that my first-generation olive egger pullet (from a BCM roo x blue Ameracauna hen) would lay brown eggs instead of olive, based on her comb (single like her dad's). Mind blown!

When people say the pea comb gene is linked to the blue egg gene, that is not quite accurate. It's more that pea-or-not is linked to blue-or-not. The genes are close together on one of the chromosomes, so they usually get inherited together.

Examples of each possible combination:
Ameraucanas have pea comb, blue egg
Cream Legbars have not-pea comb, blue egg
Brahmas have pea comb, not-blue egg
Marans have not-pea comb, not-blue egg

So pea comb can help you track the blue egg gene when you are working with Ameraucanas, but not with your CCLB (Crested Cream Legbars) because they have the blue egg gene linked to not-pea comb (single.)

Easter Eggers and Olive Eggers can be either way, depending on what breeds they got their blue egg gene from, but the pea comb/blue egg link is pretty common among them. Although I have seen some pictures of Olive Eggers that were Legbar/Welsummer crosses, with single combs.
 

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