Single comb chick from two rose comb birds? **More questions, page 3**

[WallTenters]

Quote:
http://en.wikipedia.org/wiki/Punnett_square

Use that to set up your breedings.... Rose comb genes are R. so each parent would have two copies of the R gene - either dominant (R) or recessive (r) .. actually the r means absence of the gene in most cases but that's a whole 'nother story.

So a pure rose comb bird = RR
A heterozygous (so half pure rose comb) = Rr
A single comb bird = rr

If the chick has one capital R (rose comb gene) it will have a rose comb - as this trait is dominant.

So if mating a pure rose comb bird (RR) over a half rose comb bird (Rr) you would get....
R x R = RR
R x r = Rr

50% pure rose comb and 50% half rose comb... BUT

the rose comb gene is dominant in the offspring, so they will LOOK rosecomb even though they are half single comb.

Now.... the only way that you could get a chick that looked like a single comb out of two rose comb parents is if BOTH parents were Rr.

R x R = pure rosecomb RR
R x r = rosecomb looking Rr
r x R = rosecomb looking rR (correctly written Rr)
r x r = single comb rr

Does that help? The punnett square is what you need to look at - I can't do it on this board I don't think

but it makes it really easy to draw up what your chicks are.



And thanks! Unfortunately, that comb was the only Dominique thing on the bird, he was too large and coarse and his sickle feathers didn't really come in much.

He was one we ordered, and he's now carefully watching a flock of backyard layers for a friend of myn

 

[Gypsy07]

Haha! Thank you for that link. I've just had a quick scan at the page but think I'll have to spend an hour or two reading it - with a dictionary beside me! - to have even half a chance at understanding much of it. Man, this is like being back at university. Thank you for taking the time to explain these things to me. I'm sure I'll be back in a few days with more questions.

 

[WallTenters]

No problem

Don't get too into it - the square is so easy to use, often people get confused because they think it's harder than it is. Work with just one gene for a while, then move your way up to two genes (like maybe rose comb gene, the barring gene or white gene).


trying to set up a square on our rose comb gene here for an example... For this example, both parents are Rr, so they look rosecomb but are each hiding one single comb gene.

So the father is on the top row, the mother is in the side, I have bolded the mother and father's rows... the offspring's possible outcomes are the four squares, two up and over from the bottom right hand corner.

...... R .... r
R ... RR ... Rr
r .... Rr ... rr

So...
25% RR
25% Rr
25% Rr
25% rr
we combine our two 25% Rr outcomes = 50% Rr, so 50% of the chicks are rose comb but carrying single comb gene, 25% are true rosecomb (RR) and 25% are single comb (rr)