Is there a different gene for the brown egg color and if so is it on a different chromosone. We have not mapped the brown egg genes. There are multiple genes involved in making the shell brown. Two major ones were identified, but not mapped in Bitgood's lab.
Leghorns also have a dominant inhibitor of brown shell color.
If you cross a commercial Leghorn to a New Hamp or other brown egg breed you will get a light tinted egg shell instead of an intermediate color. Because of this dominant inhibitor it is more difficult than it should be to breed back a white shell. I think that I have a candidate marker for one of the brown egg alleles, but I don't have the proper genetic lines to nail it down. This is a private posting area. A valid username and password combination is required to post messages to this discussion.