A Cornish Cross (Breeding?) Journey

[Ridgerunner]

But it has a single comb rather than a pea comb like his older sisters… and I hear the pea comb is linked to the blue egg gene

The way the pea gene is linked to the blue eggshell gene is that they are pretty close together on the chromosome. A genetics guru on here years ago said that the two genes are carried together about 93% of the time. That means he has a 7% chance of having the blue eggshell gene. Not great odds but don't give up hope.

 

[Skyeknight]

The way the pea gene is linked to the blue eggshell gene is that they are pretty close together on the chromosome. A genetics guru on here years ago said that the two genes are carried together about 93% of the time. That means he has a 7% chance of having the blue eggshell gene. Not great odds but don't give up hope.

I had heard about pea comb and blue eggs being linked before, but not to that big a decree! Do you happen to have the source post? Quite interesting that there are lots of chicken breeds that do have pea combs but lack the blue egg gene, Brahma being an example (keeping it meat bird related ). So I assume if those were used it would be 50/50 if pea comb also means blue eggs, since the Brahma chromosome would lack the blue egg gene, right?

 

[Ridgerunner]

I think that was a private message several years back so no post to link.

I did not phrase my earlier reply well. The Blue Eggshell gene and the Pea Comb gene are two totally separate unrelate genes that happen to be close together on the chromosome. If both are present on that strand then there is a 93% change both will be passed down if one is. But there are several breeds where the chicken has a pea comb and does not lay blue based eggs, like the Brahma. There are breeds that lay blue based eggs but do not have the Pea Comb, like the Cream Legbar.

The Blue Eggshell gene does not mean the Pea Comb gene is present. The Pea Comb gene does not mean the Blue Eggshell gene is present. If they are both present on the same strand they will probably be passed on together but that is not guaranteed.