Help with egg color genetics please

[tbishop]

I looked through this section and got a lot of info but none specifically for my question-

If you bred a blue egg layer (LLrr) to a brown egg layer (llRR), you would get green egg layers (LlRr) that carry recessive white shell and recesive no tint genetics. Is that correct?

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If you then bred those offspring to each other you could get 3/16 that would have the genetics for blue egg laying (either Llrr or LLrr) Isn't that the way it should work?

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I hear that it takes many generations to get back to blue eggs. This isn't suggested by the punnett square above. Is it because of how few out of the whole flock would be female with the right genetics or is it because the brown egg component have multiple factors?

 

[hwd2002]

Bantams will lay one color but it does not change during their life.
the color is usually green to blue.

 

[tbishop]

I meant to post this in the genetics discussion section. If it's more appropriate for there, feel free to move it. I apologize for adding to the work load.

 

[tbishop]

For sure- the egg color is set for life in the individual chicken. I'm talking about how many generations to get back to a blue egg layer when you cross a blue layer with a brown layer (genetically).

 

[dheltzel]

Brown egg shell color is controlled by multiple genes and that they all act independently for the most part. That is why there are so many shades of brown eggs. There is a gene that suppresses all brown egg colors at once, that is present in most commercial leghorns. I've heard it also can partially suppress blue, but I'm not certain of that, and hope it doesn't.

Basically, you need to change the Punett square from 4x4 to about 10x10 or something, so getting all the brown out (or back) is a real challenge.

 

[tbishop]

It's that "or something" I don't get. No one seems to have anything confirmed on it.

 

[dheltzel]

If you do the math, you'll realize that once you are trying to control more than 2 or 3 genes you need to hatch hundreds or thousands of chicks to be guaranteed of getting your desired results. Since the inter-relationships between these genes (and the genes themselves) are not well understood (compared to genes like blue egg color and chick down color), you are really just selective breeding for whiter (or bluer) colors to get the brown reduced. Since the males never show a phenotype for egg color, but definitely contribute to the genotype, it makes this even harder.

 

[enola]

I have proved (at least to myself) that the white leghorn egg color genes can suppress the blue color gene somewhat.

I bred my black Araucana rooster to white leghorn hens and got pullets that laid pale blue eggs. I was disappointed and posted on here about it. Someone on here mentioned the color suppression facts.

So the next spring I changed to brown leghorn hens. The resulting pullets laid a much much bluer egg.

So was that the 'suppressing' genes at work?

 

[tbishop]

Yes- 1 gene there are 4 possibilities. 2 genes there are 16 possibilities. 3 genes 64 possibilities. It grows at an exponential rate. What I don't know, and can't seem to find anything definitive on, is just exactly how many genes are involved in making brown eggs. Everyone says it's "a lot" but there has to be a fact somewhere that that opinion is based on. I just can't seem to find it. Until I see something definitive I'm going to assume two factors.

 

[tbishop]

Thank you for moving this, I posted in the wrong section by accident. Still looking for insight into this. Thanks!