Egg color again

[MyTDogs]

I have some RIR x Ameraucana mixes. The pullets are starting to lay light olive eggs. Can anyone tell me what genes the cockerels would contribute to a breeding? Would they pass on olive genes? Blue Genes? Brown?

Thanks in advance for you help!
Cindy in FL

 

[Ridgerunner]

Cindy, I don’t know if I am doing you any favors with this link, it gets kind of heavy, but we get into green eggs in this thread too.

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

I believe you are talking about the brothers of the pullets laying the green eggs, with the RIR and Ameraucana parents? Since you list both Ameraucanas and Easter Eggers in your signature, I assume you know the difference.

Those cockerels inherited a blue shell gene from the Ameraucana and a white shell gene from the RIR. That’s what we call split, at that gene pair he has a blue and a white. Blue is dominant. There is no telling which of those genes he will give to his offspring. It’s purely random. Each of his offspring has a 50-50 chance of getting a blue gene and a 50-50 chance of getting a white gene. That offspring will get a gene from their mother too.

That’s the simple part. Brown is a bit more complicated as you can see if you study that thread. There are a lot of genes that can contribute to the brown. Some are dominant, some recessive. I have no idea which brown genes he has, but he got what he has from the RIR. A true Ameraucana will lay a blue egg, which means it has no brown genes, so your cockerel will have no brown genes from the Ameraucana. So at each gene pair, he might pass on a brown gene or he might not. It’s random. Will he pass on any brown genes? It is extremely likely, but mathematically there is a possibility he will not.

It’s possible he will get an inhibitor of brown from the Ameraucana, but since his sisters are laying green eggs, it’s not likely unless it is recessive. Then it won’t show unless it happens to pair up with something from the hen he mates.

And you thought you were asking a simple question. But the short answer is he has a 50% chance of contributing a blue gene and will almost certainly pass on some brown. Green is simply blue + brown.

 

[MyTDogs]

Thanks Ridgerunner! I really appreciate you taking the time to reply. The info you posted is very helpful.