Question on my Brahma's Colour

[Finnie]

I’d assume the off-white shade is due to autosomal red, which is non-sexlinked red/gold.

Hm. I was under the impression that the sex-linked silver gene blocked the expression of the autosomal red gene. Hence a white chicken with no red or yellow showing.

 

[RoostersAreAwesome]

Hm. I was under the impression that the sex-linked silver gene blocked the expression of the autosomal red gene. Hence a white chicken with no red or yellow showing.

You’re thinking of sex linked gold.

 

[Finnie]

You’re thinking of sex linked gold.

Yes. I’m thinking of the silver gene: S, s+.

S= silver and is dominant, s+ = the non silver wild type that people call gold and is recessive. Located on the W chromosome.

When a hen has the S on her W chromosome, she cannot produce the pheomelanin that causes red or gold color. So she is white. She may genetically have autosomal red on an autosomal chromosome, but the S gene blocks her ability to express that.

That is my understanding of how the S gene works

I guess I am saying that maybe the hen in question isn’t Silver, but has something else washing out her red-gold coloring. Because if it was silver, it would wash it out completely, not part way.

 

[RoostersAreAwesome]

Yes. I’m thinking of the silver gene: S, s+.

S= silver and is dominant, s+ = the non silver wild type that people call gold and is recessive. Located on the W chromosome.

When a hen has the S on her W chromosome, she cannot produce the pheomelanin that causes red or gold color. So she is white. She may genetically have autosomal red on an autosomal chromosome, but the S gene blocks her ability to express that.

That is my understanding of how the S gene works

I guess I am saying that maybe the hen in question isn’t Silver, but has something else washing out her red-gold coloring. Because if it was silver, it would wash it out completely, not part way.

As far as I know, autosomal red can show up on silver, but I’m not really sure how to explain why. @Amer and @nicalandia might be able to say it better than me.
Here’s a thread with a hen that has what I consider autosomal red: https://www.backyardchickens.com/threads/lacing-mottling.1414241/post-23223404.

 

[nicalandia]

Yes. I’m thinking of the silver gene: S, s+.

S= silver and is dominant, s+ = the non silver wild type that people call gold and is recessive. Located on the W chromosome.

When a hen has the S on her W chromosome, she cannot produce the pheomelanin that causes red or gold color. So she is white. She may genetically have autosomal red on an autosomal chromosome, but the S gene blocks her ability to express that.

That is my understanding of how the S gene works

Roosters = ZZ
Hens = ZW

The s locus is located on the Z sex chromosome, Males have two copies(Z/Z) females can only have one copy(Z/W) Autosomal Red is located outside of the sex chromosome so Silver Hens(S/-) and Silver Males(S/S) can still show Red Coloration.

 

[Finnie]

Roosters = ZZ
Hens = ZW

The s locus is located on the Z sex chromosome, Males have two copies(Z/Z) females can only have one copy(Z/W) Autosomal Red is located outside of the sex chromosome so Silver Hens(S/-) and Silver Males(S/S) can still show Red Coloration.

Ok, thanks. I didn’t know they could still show red. I had thought it blocked them from it.

Also;
Well shoot! This was my first time trying to use Z and W instead of X and Y. Figures I would get it backwards. I am just so used to Xs and Ys. It’s going to take some practice.

 

[Finnie]

Revisiting this because I was just re-reading an article about this. I read this article a few years ago, and obviously forgot what I learned in it. But this is a great article on the genes involved in the autosomal red. The article is very in depth. You’ll need to pay close attention in order to absorb what he’s saying, and not read it while you are distracted, lol.
http://brianreederbreeder.blogspot.com/2014/01/the-expression-suppression-and.html?m=1