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Egg Genetics question

post #1 of 7
Thread Starter 
I'm a genetics newbie but had a few questions about egg coloration.

In my current flock, I have both Ameraucanas and Marans. I hatched out 3 roosters this round that I would love to keep all but unfortunately that isn't possible. My question is if the brown Maran colored egg is dominate or if the Ameraucanas blue egg is dominate. Does it matter if if comes from the female or the male? Thanks!
post #2 of 7

There are only two possibilities for eggshell color, white and blue. Blue is dominant over white. A brown egg has a white shell with a brown coating applied. A green egg has a blue shell with the brown coating applied. Both the rooster and the hen contribute genes for egg color.

If your Ameraucana are truly Ameraucana (having only blue egg genes to pass on) and not Easter Eggers, then all the resulting chicks should be green egg layers.

post #3 of 7
Thread Starter 
Quote:
Originally Posted by junebuggena View Post

There are only two possibilities for eggshell color, white and blue. Blue is dominant over white. A brown egg has a white shell with a brown coating applied. A green egg has a blue shell with the brown coating applied. Both the rooster and the hen contribute genes for egg color.
If your Ameraucana are truly Ameraucana (having only blue egg genes to pass on) and not Easter Eggers, then all the resulting chicks should be green egg layers.

Green as in olive or light blue type green? If they are EE's what would they lay?
post #4 of 7

The shade of green depends on the brown coating genes. If your Marans are really dark brown layers, than you'll get olive green layers. There are over nine different genes for the brown coating, and one bird can have several different coating genes.

An Easter Egger is defined by being any bird that potentially has at least one blue eggshell gene and doesn't meet the breed standard for Ameraucana, Araucana, Cream Legbar, or Rhodebar.

To determine whether your Ameraucana are true Ameraucana or Easter Eggers, first consider their source. If they are from a hatchery or feed store, they are probably Easter Eggers. True Ameraucana are always sold with the color variety specified. If no color was specified at time of purchase, you have Easter Eggers.

post #5 of 7
There are two genes at each gene pair on the DNA. When the egg is fertilized it gets one gene from each parent. If both genes from one parent for egg color are blue, then a blue gene will be passed down. If both genes from the other parent are white, then a white gene will get passed down. If the parent has one blue and one white, then either gene might get passed down, totally randomly.

The brown egg shell color is a lot more complicated. Instead of just one gene pair affecting brown there are many different gene pairs involved. Some of these genes are dominant, some recessive, some only act if another specific gene is there. That’s why you can get so many different shades of brown, there are a tremendous number of combinations of these genes. Pullets from the same parents can lay wildly different shades of brown or green eggs, just depending on which of these “brown” genes go passed down and how they combine.

I think you are talking about the genetics of your cockerels. If one parent was a true Ameraucana then the cockerels have one blue gene from them. If the other parent is a Marans, they received a white gene from that parent. It does not matter which parent was mother or father, that cockerel will have one blue and one white. When he fertilizes an egg, he will randomly pass down one of those. You don’t know which one.

Brown again is a lot more complicated. Blue is an absence of brown because if brown is present on blue you have green. To simplify it, assume your original Ameraucana had no brown genetics at all. That’s not always totally true because one of the genes that affects brown is a “bleach” gene, it can cause one brown gene to have no effect even if it is present. From some of the egg shell colors I get I think I have that bleach gene in my flock. This stuff can make your head swim, at least it does mine. Anyway, assume that cockerel inherited no brown genes from its Ameraucana parent and inherited brown genes from the Marans parent. Which brown genes. I don’t know. You can reasonably expect that it has a lot of different grown genes from the Marans at various gene pairs and not-brown genes at those gene pairs from the Ameraucana.

Which of these genes will it pass down at each gene pair? It’s totally random. It could be a lot of brown, it could be a lot of not-brown. Remember there are a lot of possible brown genes so there is a tremendous chance it will pass down some brown, but the results could be all over the place as far as shade. Of course you have to consider whet the hen she is mating with pass down.

If you are really interested in studying egg shell genetics you can read this thread. Follow the link in Tadkerson’s post #15.

http://www.backyardchickens.com/t/840867/clarifying-brown-egg-genetics/10

When you come to a fork in the road, take it.

 

"If you make every game a life-and-death proposition, you're going to have problems. For one thing, you'll be dead a lot." — former North Carolina coach Dean Smith

 

http://www.backyardchickens.com/a/how-much-room-do-chickens-need

Reply

When you come to a fork in the road, take it.

 

"If you make every game a life-and-death proposition, you're going to have problems. For one thing, you'll be dead a lot." — former North Carolina coach Dean Smith

 

http://www.backyardchickens.com/a/how-much-room-do-chickens-need

Reply
post #6 of 7
Thread Starter 
Quote:
Originally Posted by junebuggena View Post

The shade of green depends on the brown coating genes. If your Marans are really dark brown layers, than you'll get olive green layers. There are over nine different genes for the brown coating, and one bird can have several different coating genes.
An Easter Egger is defined by being any bird that potentially has at least one blue eggshell gene and doesn't meet the breed standard for Ameraucana, Araucana, Cream Legbar, or Rhodebar.
To determine whether your Ameraucana are true Ameraucana or Easter Eggers, first consider their source. If they are from a hatchery or feed store, they are probably Easter Eggers. True Ameraucana are always sold with the color variety specified. If no color was specified at time of purchase, you have Easter Eggers.

Okay, that is great information. They came from blue eggs and were said to be Blue Wheaton/splash Ameraucanas, however; their coloring isn't breed standard coloring. They all have slate colored legs, muffs, and beards but their coloring doesn't look exactly like what I've seen is breed standards.
post #7 of 7
Thread Starter 
Quote:
Originally Posted by Ridgerunner View Post

There are two genes at each gene pair on the DNA. When the egg is fertilized it gets one gene from each parent. If both genes from one parent for egg color are blue, then a blue gene will be passed down. If both genes from the other parent are white, then a white gene will get passed down. If the parent has one blue and one white, then either gene might get passed down, totally randomly.

The brown egg shell color is a lot more complicated. Instead of just one gene pair affecting brown there are many different gene pairs involved. Some of these genes are dominant, some recessive, some only act if another specific gene is there. That’s why you can get so many different shades of brown, there are a tremendous number of combinations of these genes. Pullets from the same parents can lay wildly different shades of brown or green eggs, just depending on which of these “brown” genes go passed down and how they combine.

I think you are talking about the genetics of your cockerels. If one parent was a true Ameraucana then the cockerels have one blue gene from them. If the other parent is a Marans, they received a white gene from that parent. It does not matter which parent was mother or father, that cockerel will have one blue and one white. When he fertilizes an egg, he will randomly pass down one of those. You don’t know which one.

Brown again is a lot more complicated. Blue is an absence of brown because if brown is present on blue you have green. To simplify it, assume your original Ameraucana had no brown genetics at all. That’s not always totally true because one of the genes that affects brown is a “bleach” gene, it can cause one brown gene to have no effect even if it is present. From some of the egg shell colors I get I think I have that bleach gene in my flock. This stuff can make your head swim, at least it does mine. Anyway, assume that cockerel inherited no brown genes from its Ameraucana parent and inherited brown genes from the Marans parent. Which brown genes. I don’t know. You can reasonably expect that it has a lot of different grown genes from the Marans at various gene pairs and not-brown genes at those gene pairs from the Ameraucana.

Which of these genes will it pass down at each gene pair? It’s totally random. It could be a lot of brown, it could be a lot of not-brown. Remember there are a lot of possible brown genes so there is a tremendous chance it will pass down some brown, but the results could be all over the place as far as shade. Of course you have to consider whet the hen she is mating with pass down.

If you are really interested in studying egg shell genetics you can read this thread. Follow the link in Tadkerson’s post #15.

http://www.backyardchickens.com/t/840867/clarifying-brown-egg-genetics/10

Wow, that is a lot of fantastic information and yes my mind is swimming but I think I swallowed some of the basics!

That definitely answers my question if the AM cockerel was the only way to have blue tinted eggs to be sure whom I kept of the 3 Roos. So much information!
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