Egg Colour Genetics Question

[TheWriteChick]

This is all fascinating! I have 5 Easter Eggers and get a variety of green and blue, some with spots, some more brown than green. So, basically, it seems that all my girls have a blue egg gene, and some also have the "set" of genes that leads to brown. I don't have plans to breed at this point, living in a neighborhood, but it makes the possibilities interesting!

 

[The Moonshiner]

That is still not quite right. At one locus, you have blue or not blue (not necessarily white). At another locus, you have white or brown, and that is incompletely dominant (so, it can be white, tinted, or brown). That works with the other locus, and if it codes for blue, it can range from blue to green to olive. At other loci, you have modifiers for intensity of brown, if brown is coded for already. If that does not make sense, i can try to explain it better.

I tried to keep it simple cause I'm a simple kind of person and I know getting too detailed makes it hard for some to follow. In the process I'm probably off a bit or didn't explain it quite right but it Isn't that far off.
I disagree with you. There is no brown egg gene or at least no brown egg gene like blue or white. Brown eggs are white eggs with brown coating. Look at any brown egg on the inside of the shell its white not brown.

 

[junebuggena]

That is still not quite right. At one locus, you have blue or not blue (not necessarily white). At another locus, you have white or brown, and that is incompletely dominant (so, it can be white, tinted, or brown). That works with the other locus, and if it codes for blue, it can range from blue to green to olive. At other loci, you have modifiers for intensity of brown, if brown is coded for already. If that does not make sense, i can try to explain it better.

No. There are only two options for shell color, white or blue. Blue is a dominant mutation of the white shell gene. Brown is a completely different set of genetics, and there are multiple genes involved. The genes for the brown coating are very complex and not well understood at all, since there are so many factors involved. That is what gives us so many different shades of brown, from lightly tinted cream to deep chocolate brown.
According to your information, a white laying breed crossed with a brown laying breed would produce tinted laying offspring. That simply is not true.

 

[gojira]

No. There are only two options for shell color, white or blue. Blue is a dominant mutation of the white shell gene. Brown is a completely different set of genetics, and there are multiple genes involved. The genes for the brown coating are very complex and not well understood at all, since there are so many factors involved. That is what gives us so many different shades of brown, from lightly tinted cream to deep chocolate brown.
According to your information, a white laying breed crossed with a brown laying breed would produce tinted laying offspring. That simply is not true.

Read Heredity in Poutry by Punnett, and Genetics of the Fowl by Hutt. What I mentioned was studied over 100 years ago, and is not new. All eggs start out white. They can have a blue pigment added, or brown, both, or nothing. Yes, one locus determines if any brown is added, and others modify the degree. It is ver common knowledge, and has been for over 100 years that crossing a white egg laying breed with a brown laying breeds makes females that lay tinted eggs. I guess the chicken calculator did not teach you that.

 

[junebuggena]

You REALLY need your educator badge revoked. Read Heredity in Poutry by Punnett, and Genetics of the Fowl by Hutt. What I mentioned was studied over 100 years ago, and is not new. All eggs start out white. They can have a blue pigment added, or brown, or nothing. Yes, one locus detrrmines if any brown is added, and pthers modify the degree. I guess the chicken calculator did not teach you that. You would not pass a test on the first week of a poultry genetics class, yet you brag you know poultry genetics, and mislead people. Why? I will offer to mrbtor you if you are serious about learning poultry genetics. If you refuse to learn, I really think they should remove the educator badge since you don't know poultry genetics.

Exactly what did I say that was misleading? It was all true. Perhaps you need to look into some more recent research. It's possible that your 100 year old reference may be out of date and inaccurate. There has been quite a lot of research done on blue shell genetics in the last 50 years.

 

[The Moonshiner]

Isn't it true that a white egg is a white shell and a blue egg is a blue shell? But a brown egg is a white shell with brown applied to the outside and a green egg is a blue shell with brown applied to the outside?
If you cross a blue egg layer (2 copies) with a brown egg layer (2 white genes and two sets of what produces brown?.Right?)
Then you get a green egg layer. But it carries 1 blue egg gene, 1 white egg gene and the brown egg producing genes from the one parent?
So to the OP their birds or the green egg layers can pass either a blue egg gene or a white egg gene. And could or could not pass anything related to the brown genes but would most likely pass some of the genes to produce brown coating but by odds they would get less then their parent but at least enough to tint their eggs beyond blue or white? Right?

 

[gojira]

Isn't it true that a white egg is a white shell and a blue egg is a blue shell? But a brown egg is a white shell with brown applied to the outside and a green egg is a blue shell with brown applied to the outside?
If you cross a blue egg layer (2 copies) with a brown egg layer (2 white genes and two sets of what produces brown?.Right?)
Then you get a green egg layer. But it carries 1 blue egg gene, 1 white egg gene and the brown egg producing genes from the one parent?
So to the OP their birds or the green egg layers can pass either a blue egg gene or a white egg gene. And could or could not pass anything related to the brown genes but would most likely pass some of the genes to produce brown coating but by odds they would get less then their parent but at least enough to tint their eggs beyond blue or white? Right?

No, that is not right. All egg shells begin as white. Blue is caused by oocyanin, and it penetrates all the way through the shell. Brown is caused by protoporphorin in the cuticle and the egg shell. You are completely confused. Read my previous posts. If you can't understand them, let me know. That is as simple as I can make it without breaking things down to details.

 

[The Moonshiner]

Sounds like you're saying the same thing.
White is white. Blue is blue. Both all the shell, inside and out.
Brown is on the outside of the shell but not in the complete shell. Brown can be on the outside of a white egg or on the outside of a blue egg.

 

[gojira]

Sounds like you're saying the same thing.
White is white. Blue is blue. Both all the shell, inside and out.
Brown is on the outside of the shell but not in the complete shell. Brown can be on the outside of a white egg or on the outside of a blue egg.

You keep saying an egg is white or blue, and that is not correct. It would be easier with a flow chart. All eggs start as white. The genes code for blue or brown, and other genes code for modifiers of brown (they can even affect shade in absence of brown). So, if an egg is brown or green, the gene for white eggs may be absent, or it could be present in a heterozygous state. One way to think about this is that brown can be added to a white shell, or a white shell after blue has been added.

 

[The Moonshiner]

So you can have a brown egg that is not on a white shell?
So there are eggs that are brown inside and out?
I agree eggs start out as white and agree they can code from white to blue. You can quit repeating that part.
I believe the shell is either going to be white or blue. That's the only choice. There is no brown or green shells. There is no brown egg that isn't on a white shell and green is the same brown on a blue shell.
You replies seem to be saying the same thing and at the same time you're saying its not correct.