Egg color genetics?

LunaMarieWolf

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Dec 31, 2018
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I have a question about egg color genetics.

Does the roo pass on the egg coloration to his children? Is it the hen who passes the gene on? Or is it a mix of the parents eggs colors.

Like if you breed a brown layer roo to a white layer hen, is the daughters of this mix going to lay white, brown, or a mix like a creme?

I had a Barred Roo (brown layer) that I crossed with an EE (blue layer), and their daughters laid brown eggs.. so I am just very confused.
 

ChocolateMouse

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It's a mix of both. Genes come in pairs and each parent passes down one. Some genes, like blue egg color, are easy to track and are 'simple' dominant or recessive. Others like brown are produced with a mix of genes that vary the intensity of the brown from nearly white all the way to marans dark red.

Genes are rarely passed down by just one parent, and usually when they 'are' it's a misnomer. Usually it's something like chromosomes where one parent has two of the same kind (ZZ) and the other has two different (ZW) so it's "determined" by the parent who has the mix, but they both still pass one down.

https://scratchcradle.wordpress.com/genetics-mini-series/
This website has a great primer on egg color genetics and I love using it as a reference.
 
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ChocolateMouse

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In the case of blue egg genes it's what's called a simple dominant gene. A dominant gene presents if just one of the two genes in the pair is "on". A recessive gene only presents if both genes in the pair are "on".

Genes always come in pairs, and in this case the blue egg color is a simple pair of genes that act a little like light switches with blue light bulbs in a room. They're totally separate from white/brown egg color.

If both switches are off you get the 'normal' room color (white or brown). If one switch is on you get the blue color, plus whatever color the room is. If the room is brown you get a greenish tint if the room is white it's just blue now. If both switches are on the room is still blue/green but maybe a little bluer.

So your rooster has two light switches off with a brown egg. And your easter egger has one light switch on (blue) and one off (not blue). Probably also a brown egg without the blue (that's what most easter eggers are).

The chicks just happened to randomly get one off switch from dad and one off from mom. So all that's left is the 'normal' brown egg color.

Since the blue egg gene is dominant, it only takes one gene being "on" to see it. We know that if your hen had two blue egg genes turned "on" she would have HAD to pass at least one down to her chicks. So we can determine from simple elimination that your hen has only one copy of the blue egg gene turned on, so only half her chicks, on average, will lay blue-tinted eggs and the rest will be left up to white/brown genetics.
 

The Moonshiner

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Genes are rarely passed down by just one parent, and usually when they 'are' it's a misnomer. Usually it's something like chromosomes where one parent has two of the same kind (ZZ) and the other has two different (ZW) so it's "determined" by the parent who has the mix, but they both still pass one down.

There's a few genes that are referred to as sex linked genes.
In your ZZ ZW example there is no place for them on the W so the hen only has one copy and not two. That means with those sex linked genes she only inherits a gene from her father and only passes it to her sons. Because theirs not one one the W that she inherited.
So yes there are some cases where a female doesn't get a gene from both parents.
 

ChocolateMouse

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There's a few genes that are referred to as sex linked genes.
In your ZZ ZW example there is no place for them on the W so the hen only has one copy and not two. That means with those sex linked genes she only inherits a gene from her father and only passes it to her sons. Because theirs not one one the W that she inherited.
So yes there are some cases where a female doesn't get a gene from both parents.

So.... Rarely, which is what I said? :p K.
 

Amer

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There's a few genes that are referred to as sex linked genes.
In your ZZ ZW example there is no place for them on the W so the hen only has one copy and not two. That means with those sex linked genes she only inherits a gene from her father and only passes it to her sons. Because theirs not one one the W that she inherited.
So yes there are some cases where a female doesn't get a gene from both parents.
X2
@nicalandia has shown us some fine examples of how a white Leghorn cock over a brown laying hen will produce pink eggs while vice versa will produce a more medium shade.
However, in both cases, the color of eggs is controlled by both parents.
 

nicalandia

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There has been extensive studies on the subject of egg color inheritance, brown egg shell color is a polygenic trait and a few of them are indeed sex linked at least two. The reciprocal cross of brown eggers with White eggers will yield darker shade of eggs when the sire is the brown egger.

In your specific case your EE hen was only heterozygous for the blue egg shell gene, so so you had 50% chance of hatching brown eggers and that is what you just hatched
 

slordaz

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Thank you all still don't get a lot of it but was more understandable than most explanation, and it wasn't cause you did a bad job just not enough caffeine yet, I will reread that when I'm fully awake lol

if it looked liked the aliens from MIB were typing just tell me to note type until I've had plenty of coffee lol
 

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