Pea comb dominance

[nicalandia]

Quote:
ok I will try to explain...pea comb (gene letter P) is dominat to recessive single comb (gene letter p+) cochins are Homozigous for single comb p+/p+, recessive genes can only show up in Homozigous form not Heterozigous, dominant genes can show in Homozigous and Heterozigous forms, a Pea comb birds can be P/p+ (dominat Pea comb/recessive single comb) and can also be P/P(dominat Pea comb/dominant Pea com)...if you mate a Homozigous dominant Pea comb chicken(P/P) with a Homozigous recessive single comb chicken(p+/p+) ALL of you chicks will have Pea combs, but they are Heterozigous for Pea comb only(P/p+) now if you cross that Heterozigous bird to a Recessive single com chicken(p+/p+) you´ll get 50% chicks with Pea comb (P/p+) and 50% will be Homozigous for recessive single comb(p+/p+).....I hope you I didn´t confused you even more...

 

[Rootball]

Quote:
ok I will try to explain...pea comb (gene letter P) is dominat to recessive single comb (gene letter p+) cochins are Homozigous for single comb p+/p+, recessive genes can only show up in Homozigous form not Heterozigous, dominant genes can show in Homozigous and Heterozigous forms, a Pea comb birds can be P/p+ (dominat Pea comb/recessive single comb) and can also be P/P(dominat Pea comb/dominant Pea com)...if you mate a Homozigous dominant Pea comb chicken(P/P) with a Homozigous recessive single comb chicken(p+/p+) ALL of you chicks will have Pea combs, but they are Heterozigous for Pea comb only(P/p+) now if you cross that Heterozigous bird to a Recessive single com chicken(p+/p+) you´ll get 50% chicks with Pea comb (P/p+) and 50% will be Homozigous for recessive single comb(p+/p+).....I hope you I didn´t confused you even more...

That was a good explanation however some might not get it. People need to start doing about 30 mins of genetics research before they start asking all these questions. It really isnt rocket science, and as I say 30 mins can put you way ahead in your understanding.

Some things to look up...Punnet Squares , and classical genetics.

Just remember with (almost every but not all) genes each bird has 2 things to give but each offspring only gets 2 things(not 4) and 1 of these things comes from the father and one of these things comes from the mother and the cycle begins again. That bird has 2 things to give and he mates with something else with 2 things to give, but the offspring only gets 2 things.

With every mating 2 things are lost. every bird has 2 things but gives only one.

but it varies with offspring if your bird has genes for pea comb and single comb he himself will have a pea comb. But he will give single comb genes to half his kids and pea comb genes to half his kids. so if his wife is the same as him(split for pea) she will look pea combed but she will give half her kids pea comb and half single combs.

However here is the rub and here is where you need a punnett square. In this square I use P for Pea comb and p+ for single. the Pp+ on top is one parent and the Pp+ on the left represent the other parent. The 4 groups of letters represent possible groupings from the given parents.


P p+

P PP Pp+

p+ Pp+ p+p+


Notice that each parent is split for P (P/p+) and so they will have pea combs, and they will each give 50% of their offspring each type of comb, BUT when combined we get:

75% pea combs and 25 % single combs. This is referring to appearance. because we actually got 3 different kinds of birds. 25% are pure for pea comb (PP) 50% are split for pea and single (Pp+) and 25% are pure for single combs(p+p+). From appearance there is no way to tell Pp+ from PP and this is why flocks of pea combed birds will sometimes throw a single comb, because Pp+ birds will sometimes get together.

 

[nicalandia]

No harm in asking............

 

[KinderKorner]

Everyone has always told me the pea comb was dominant. But I bred EE/RIR. And EVERY chick had a single comb. I grew probably 20 of these.

Then I bred back the single combed EE/RIR to another EE.

And guess what. Babies still have single combs.

I am 100% positive on the parents. So whats happening?

I have taken a genetics class but it's been a while. lol

I just can't see how everyone one of my chicks are single combed.

 

[ChooksChick]

What about other comb types? I have been experimenting with an EE roo over Buttercup hens, and I get a very interesting modified comb that is single leading up to the top 1/4th, which splits into a cup. Occasionally I get a triple comb, which looks like the three rows of a pea comb, but with teeth! I call these birds 'Butterpuffs' because the coloring looks like a silver Buttercup with beard and muffs.

So what can anyone tell me about that? The pea doesn't apear dominant in that case, either, but it's not an either/or situation such as with pea/single.

 

[karabbitry]

Everyone has always told me the pea comb was dominant. But I bred EE/RIR. And EVERY chick had a single comb. I grew probably 20 of these.

Then I bred back the single combed EE/RIR to another EE.

And guess what. Babies still have single combs.

I am 100% positive on the parents. So whats happening?

I have taken a genetics class but it's been a while. lol

I just can't see how everyone one of my chicks are single combed.

This is exactly what Rootball had explained. The pea combed bird in both instances is a hetero for the pea comb i.e. Pp. When this is crossed to a single comb, which is recessive...p/p you can hatch out both pea combed birds that are incomplete P/p and single combed birds that are p/p. I know that on paper you are supposed to see a 50% of each comb type but mother nature didn't take statisics...so it does not happen right each time.

When you crossed the EE/RIR SC birds which are p/p back to another EE and got all Single combed birds that means that the EE used in the secomd cross is a P/p, a hetero.

Basically like I said Mother Nature didn't take stats and that leads to numbers that don't add up right especially in small groups as you descibed.

ChooksChick...I don't have a clue what the Buttercup type comb does! I am sure others will know...but can't help at all

 

[Sonoran Silkies]

Quote:
The part in bold is incorrect. Everything else is correct. What is displayed is not random, but is based upon the dominance of the alleles present in the bird.

 

[Sonoran Silkies]

Quote:
I'm not sure why that phenotype sometimes shows up and sometimes does not. I've also heard of Het. pea combed bird with a taller pea comb--kind of like it took the base partion of the single comb and added the pea comb on top.

 

[CynthiaM]

Quote:
Well, holy smokes!!! I was re-reading this topic and looked up classical genetics on the internet -- and I have bookmarked and been studying this page: http://humangenetics.suite101.com/article.cfm/genotype_phenotype_inheritance

I have been studying now for a couple of hours and feel like I have barely touched the tip of that iceberg and really am not quite understanding it at all, yet. Just so you know, smiling. I am not giving up. It is my intention this winter to become informed about genetic stuff and now you have sent me onto a huge studying quest, smiling again. I will master these simple (ya right) concepts, but it really is not just a half hour thing for me to understand even a portion of this stuff. But I am trying. My biggest thing is how to pronounce:

heterozygous

and

homozygous

and never mind trying to remember how to spell these two words, smiling again, and again, and again. Have that wonderful day, CynthiaM.

 

[speckledhen]

I am hopeless with the gene designations of genetics so those completely confuse me! I have hatched quite a few BR over BBS Ameraucana hens and none have a single comb. Some get that "wad of chewing gum" and/or floppy comb, some get what someone else described as what looks like the base part of a single with the points cut off. I have one hen who is blue Orp over Buff Brahma and she has a pretty decent pea comb, closest to a pure pea comb I've seen in my crosses of single/pea. Never once have I or anyone I know gotten a truly single combed-looking bird from those crosses out of my own flock; not to say it cannot happen since genes are like tricky little leprechauns sometimes.