Question about comb genetics

[caseebeths]

If I have a Rooster with a walnut and breed him with a single combed hen...it is to my understanding it will produce all walnut comb babies? ?? Then if I breed those babies with all walnut comb mates will they continue to produce just walnut combed offspring? ?Can sosomeone advice me on this

 

[Makomd]

If walnut combs are similar to rose combs than you would still have to watch the offspring. In rose combs - Rose combs are dominant. R while single combs are recessive r.

An R/R bird bred to a r/r bird will result in R/r. Bird shows rose comb, but is hiding a recessive single comb gene (50%).

Breed this R/r bird back to an R/R bird and you birds will still be rose comb birds but (25%) will still be R/r.

You could just breed your crossed birds back to a r/r bird and hatch out some eggs if all hatchings show the walnut then it is carrying a recessive single comb gene. if all hatching are walnut it is carrying both walnut genes and I would breed this bird going further and test for other birds that breed pure also.

I do believe if I read it correctly walnut is a dominant as well over single comb.

Check out this link it may help as well.


https://www.backyardchickens.com/a/comb-genetics

 

[Spangled]

If I have a Rooster with a walnut and breed him with a single combed hen...it is to my understanding it will produce all walnut comb babies? ?? Then if I breed those babies with all walnut comb mates will they continue to produce just walnut combed offspring? ?Can sosomeone advice me on this

Not exactly, but eventually. It seems to be a little more complicated than that.

I consider a walnut and a cushion to be basically the same because it seems that it's just enhancers or modifiers that account for the difference in shape. (supposed to be P/P R/R or something like that to be "Pure." P=Pea, R=Rose) But, yes, I do understand that some breeds are specifically supposed to have a walnut and some are specifically supposed to have a strawberry. In those cases, it's not the same thing to me.

What's been happening for me is that when I cross a "pure" walnut or a "pure" cushion with a "pure" single comb is that I very often get another cushion or walnut.

But when I take that next generation and successive generations and cross again with a single comb, I will sometimes get a bigger pea comb with funny rose comb protuberances on it. I can sometimes get a cushion, but not very often. When I breed that funny comb with another non-pure cushion, I can get a decent cushion or walnut, but I can also get something a little more like a walnut with a spike like on a rose comb or just about anything in between that looks like a big or normal sized pea, rose, or walnut/cushion.

If I breed my cushion offspring (second generations) back to a "pure" parent or aunt/uncle, I will get some decent cushions, but I still will also get rose and pea comb conglomerations of differing sizes. The decent cushions are not likely going to be R/R, P/P even though they will often show up as a cushion. Their brothers and sisters will often have variations of pea combs and rose combs.

You may get larger wattles also when you breed in a single combed chicken. (Usually walnut combed chickens have smaller wattles.)

There are modifiers and enhancers, etc., in comb genetics that aren't well understood yet--not just by me, but by real genetic experts. I've also heard talk of "incomplete dominance," which sounds like a good explanation. Trial and error is the way to get the type of comb you want, if you want something specific. I don't think this is a test mating issue because it's really not something firm that you can plan for very well because of the modifiers and enhancers, etc., which I don't think are specifically identified yet. I believe crests can further complicate the issue also.

So walnut combs may be dominant over single combs, but it's not dominant in the same way an E/E black chicken being bred to a red chicken (eb/eb) where all the chicks (offspring) will almost assuredly be black because E/E is dominant over (eb/eb).

 

[Makomd]

Spangled is correct. Cushion/walnut comb is a combination of Rose Comb and Pea Comb. Another good thread on combs here.

https://www.backyardchickens.com/t/606259/comb-genetics