Here is my understanding of comb genetics for pea, rose, and single (others may refine):
2 genes control pea expression. 2 genes control rose expression. A chick receives one set from each parent.
Pure pea comb is shown as PPrr. 2 pea genes (being pure bred) and no rose genes.
Pure rose comb is shown as RRpp. 2 rose genes (being pure bred) and no pea genes.
Pea is dominant. Rose is dominant. If no rose genes are present, 1 pea will express pea comb. If no pea genes are present, 1 rose will exhibit a rose comb.
If no rose or pea genes are present, it is a single comb. Single comb is absence of other modifiers...no rose or pea genes. It is a single comb.
If BOTH pea and rose are present, you get a walnut comb.
Wave and funk happen when mixed comb types are bred, and can simply happen even in breeding lines.
Pure breeds, like the pure Brahma hens, should have PP. The hen will offer one of her P genes each time. She has no rose genes, so will offer no rose genes (rr).
If your rose comb hen was pure, she will be RRpp. (2 rose genes). If not, or simply hatchery quality, she could be Rrpp (1 rose comb gene).
Your standard single comb hen will be rrpp...no rose or pea combs to offer.
So then you work the Punnett Square math running your crew over each rooster.
Single Combed Rooster
The single comb rooster won't add anything to the comb, so the hen's comb will dominate.
Your brahma mixed chicks from him should be pea combed (and foot feathered).
Your rose comb hen with that single comb rooster will produce rose comb chicks 50% of the time, and single comb 50% of the time if she was a mixed gened. 100% rose comb chicks if she was a pure breed.
Wyandotte Rose Comb mix rooster
Since your rose comb rooster was a mix, we know he was Rrpp.
Rose is dominant over the single comb hen, so will produce 50% rose comb and 50% single comb...since only 1 rose gene is available to offer....and hopefully some other color marker to know her chicks.
That roo with the Brahma gets a bit trickier. Brahma will be PPrr (if pure). Your rooster was Rrpp.
So doing Punnet Square math (if I did the square right) your genetic chances are:
50% RrPp....which will produce some type of walnut comb...both rose and pea expressing produce walnut
50% rrPp....which will produce a pea comb
That rose comb mixed rooster with the rose comb hen will produce rose comb chicks 100% if the hen was pure. 50% rose, 50% single if the hen was Rrpp....and hopefully with some color to track.
That rooster over the single comb hen, assuming she is truly rrpp, will produce rose combs 50% and single combs 50%.
So you will have a mixture of chicks with that bunch. You will know Brahma is involved if a pea comb or a walnut show up.
However, the rose comb could come from the rose comb hen or the single hen.
Whew...hope I got all that right
LofMc
