Genetics and crossing breeds

[kidseieio]

I am a small chicken hobbyist that has had a chicken addiction for years. As I have my Roos with their girls we have enjoyed the different mixes we get. I am trying to learn more about the genetics etc but wondered if there is ever a "general" statement that can be made about crossing breeds. For example , in creating a sex link, the roo passes feather trait to girls And hen passes to baby roo's. so would this not be a general factual statement for all breed crosses? That feather color is passed to opposite sex offspring?

 

[Henk69]

No, that only applies to sexlinked genes, and to be clear: the males always get influenced by both parents.

 

[tadkerson]

I am a small chicken hobbyist that has had a chicken addiction for years. As I have my Roos with their girls we have enjoyed the different mixes we get. I am trying to learn more about the genetics etc but wondered if there is ever a "general" statement that can be made about crossing breeds. For example , in creating a sex link, the roo passes feather trait to girls And hen passes to baby roo's. so would this not be a general factual statement for all breed crosses? That feather color is passed to opposite sex offspring?

There are very few general statements that can be made concerning chicken genetics. You have to look at each gene and how that gene is expressed in a chicken and how the gene interacts with other genes in a chicken to produce a phenotype ( birds appearance).

The only ones that I know of are the principles of genetics; dominance verses recessive, sex linkage, hypostatic vs epistatic, autosomal linkage, independent assortment, etc.

Take for example the blue gene. If a blue bird is crossed with a black bird ( extended black and melanotic), you should get 50% black offspring and 50% blue offspring. The percentages are dependent upon chance so there will be some variation in the percentages. If both parents are carriers of recessive white then, the results ( percentage of offspring) are thrown out the window. The new results would be 25 % white, 37.5 % blue and 37.5 % black. If you throw in recessive lavender, it really messes up the percentages ;25% white , 18.75 % black, 18.75 % blue, 18.75 % self blue (lavender) and 18.75 % platinum ( light blue).

In this case, the recessive white gene is epistatic to all the other genes ( blue, extended black and melanotic, and lavender). The blue and the lavender are both epistatic to the extended black gene. The blue gene is hypostatic to the melanotic genes. The lavender gene is epistatic to the melanotic genes.

The recessive vs dominance principle applies in the above example but some times you can throw that out the window. For example, the partridge phenotype. The pattern gene is normally incompletely dominant but is not even expressed in the male adult plumage. A partridge male looks very much similar to a brown male ( black breasted red). The female plumage will express the pattern genes and she will have the partridge pattern; two pattern genes in a male are hypostatic or hidden by the brown gene. The pattern gene is incompletely dominant and epistatic ( influences the brown gene) in a female but hypostatic in a male. The pattern gene does not influence the expression of the brown gene in a male bird (hypostatic).

As you can see it is all very complicated- so general statements are difficult to adhere to.


Tim

 

[Henk69]

If that didn't scare him away...

I have another general remark. Most chicken colors are best when purebreed. A lot of chicken genes are not 100% dominant, that is one of the reasons. In other animals it is much simpler.

 

[Brandi Leigh]

What breeds are you crossing?

 

[jbgwilliams]

It would be sooooo cool if we could try this,


frizzle x frizzle frizzle silkie x frizzle silkie
= =
frazzle frazzle silkie

frazzle x frazzle silkie

=
?

 

[Henk69]

It would be sooooo cool if we could try this,


frizzle x frizzle frizzle silkie x frizzle silkie
= =
frazzle frazzle silkie

frazzle x frazzle silkie

=
?

That would be called a "sorrie"