eggcolor

[Sonoran Silkies]

I've never heard of any, but then I never heard of any sex-linked genes relating to brown eggshells, either. Which gene?

 

[seriousbill]

According to what I've read, there is an inhibitor of brown coloring that is sex-linked. I believe it is noted "pr":

This recessive gene results in a lack of protoporphyrin pigment (the brown eggshell pigment) even in hens with polygenic brown eggshell color.

There's also some speculation that one of the dark brown egg shell genes (as in Marans) is sex-linked, but it's only a hypothesis as far as I know. Still, I've read about it more than once, and since brown egg shell color is so complicated, it seems plausible. However, to my knowledge, nobody's proven this yet.​

 

[warhorse]

Quote:
The male plays a bigger role in brown egg shell color, because one or more of those traits are sex-linked. But blue egg shell color is autosomal. And ,to my knowledge, there aren't any known modifying factors that are sex-linked to go along with it. Someone fee free correct me on that if I'm wrong.

So, for instance, in an ameraucana x leghorn cross the offspring would likely lay blue/green eggs but the body type and characteristics might be a crapshoot and wouldn't necessarily matter whether it was male leghorn -> female ameraucana or vice versa?