Chicken combs. How to breed for different types?

[CHICKENX2005]

I'm wondering how different chicken comb genetics work.
What comb types are dominant and which ones are recessive?

What would you get if you mix a hen with a pea comb and a roo with a single comb and vice versa?

Are there any other genetic traits that are associated with different comb types. Like health problems or being more hardy?

I have chickens with rose, single, V, and pea combs. I would like to have mostly pea combs in future generations are any of these comb types more dominant than a pea comb type. So should I not breed with some of these of I want mostly pea combs. I have a rooster with a pea comb and a rooster with a single comb if I use the rooster with the single comb will it make most of the chicks have single combs or are the other types more dominant?

I know this is a lot. Sorry I just don't know much about comb genetics and I know that a lot of you are very knowledgeable about stuff like this.
Thank you so much in advance

 

[Amer]

What comb types are dominant and which ones are recessive?
Rose and pea combs are dominant single is recessive. V-comb is incompletely dominant.
What would you get if you mix a hen with a pea comb and a roo with a single comb and vice versa?
You would get pea combs but pea isn’t completely dominant. A bird with a pea comb carrying the single combed gene can usually still be told apart from homozygous pea combed birds. The middle row of the comb will be taller than the outer rows.
Are there any other genetic traits that are associated with different comb types. Like health problems or being more hardy?
Rose and pea and walnut combs are less likely to freeze.
A specific allele of the rose comb gene also causes lower sperm motility and therefore lower fertility but it doesn’t effect health.
The pea combed gene also causes smaller wattles.
I have chickens with rose, single, V, and pea combs. I would like to have mostly pea combs in future generations are any of these comb types more dominant than a pea comb type. So should I not breed with some of these of I want mostly pea combs. I have a rooster with a pea comb and a rooster with a single comb if I use the rooster with the single comb will it make most of the chicks have single combs or are the other types more dominant?
Just breed pea comb to pea comb.
Otherwise single combs will pop up in future generations.

By the way, peaxrose causes walnut combs. Neither is more dominant since they are separate genes. But it will also mean single combs in future generations.
Duplex combsxany other comb will create a double version of that comb type.

 

[talkinboutchickens]

I don't know anything about genetics either, all I known is that when a single-combed roo mated with my easter egger with a pea comb their chick had a pea comb.

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[Amer]

Although if you want *mostly* pea-ish combs with some single combs I guess breeding pea to single is ok.

 

[DarJones]

Single comb and pea comb are different alleles of the same gene on chromosome 1. Rose comb is from a combination of the rose comb inversion on chromosome 7 plus single comb on chromosome 1. Rose comb on chromosome 7 plus pea comb on chromosome 1 gives walnut comb. Two versions of rose comb are documented as R1 and R2. R1 whacks an adjacent allele reducing sperm viability. R2 basically repairs the damaged sperm allele leaving the rose comb inversion intact. I have not broken down the genetics of other comb types such as inverted, cushion, strawberry, buttercup, and carnation. Several comb expressions are from 2 or more genes interacting. Jerry Foley's Silver Laced Wyandottes have a very flat rose comb which is from single comb on chromosome 1, rose comb on chromosome 7, and the inverted gene which is not documented to a chromosome.

Comb type is sexually dimorphic meaning females have different expression than males. Single comb hens generally have a comb about 1/4 the size of a rooster's single comb.

 

[NatJ]

I have not broken down the genetics of other comb types such as inverted, cushion, strawberry, buttercup, and carnation.

Cushion and Strawberry are types of walnut comb. By that I mean that pages about genetics calls them walnut comb because they have both the pea comb gene and the rose comb gene. The people writing the official descriptions for chicken breeds, before the genetics were understood, named the comb types according to what they looked like.

Buttercup and V are caused by different alleles at a third locus (Duplex), different than pea or rose. The Duplex locus has at least three alleles (V, Buttercup, and whatever you call the normal one that is recessive to both.)

Single comb and pea comb are different alleles of the same gene on chromosome 1. Rose comb is from a combination of the rose comb inversion on chromosome 7 plus single comb on chromosome 1.

But the comb type we call "single" requires a specific allele at one locus (the pea comb locus) AND a second locus (the rose comb locus) AND a third locus (the Duplex locus).

So I would say single comb is not-pea, not-rose, and not-duplex as a way to express that it requires the recessive at all three loci.

I'm wondering how different chicken comb genetics work.
What comb types are dominant and which ones are recessive?

Pea comb is caused by a dominant gene.
Rose comb is caused by a different dominant gene.
Duplex comb (V or Buttercup) is caused by a dominant gene that is different yet.
Each of those genes is at a different place on the chicken's chromosomes, so the chicken can have them in any combination.

Single comb is recessive to all of them. It needs the recessive not-pea gene, and the recessive not-rose gene, and the recessive not-duplex gene.
Breeding two chickens with single combs will give chicks with single combs, nothing else.

The rose comb gene is completely dominant. If you see a chicken with a rose comb, you cannot tell whether it has one or two genes for rose comb, because it looks the same either way. That, plus the fertility issue mentioned by @DarJones , is why single combs pop up sometimes in rose comb breeds (you can't spot who is carrying the not-rose gene and cull them, and the roosters that are split for rose and not-rose sire more than their fair share of the offspring.)

The pea comb gene is considered incompletely dominant. A chicken with one copy of the gene has a comb that looks different than a single comb: points are less tall, comb is thicker, may have an extra ridge on each side or bumps on each side, may look blobby and hard to describe. Occasionally fools people either way: either by looking almost exactly like a single comb, or by looking almost exactly like the pea comb of a chicken that has two copies of the gene.

A chicken with two copies of the pea comb gene has a smaller comb, and smaller wattles, and a strip of skin along the breastbone that looks a little funny and doesn't grow feathers. The smaller comb and wattles are good in cold climates. The skin difference doesn't really matter because they usually have plenty of feathers to keep warm anyway, but it looks a little different if you are serving a roasted chicken for dinner (some people care, some don't, but I have read that is why the pea comb of purebred Cornish chickens was bred out of the stock that produce modern Cornish-Cross meat chickens).
https://www.sciencedirect.com/science/article/pii/S0032579119489530
^This is one article that mentions the "breast ridge" on the skin of pea combed chickens.

Rose + pea makes a walnut comb. The chicken can have one rose comb gene or two, and it will look the same either way. The walnut comb and the wattles are smaller if the chicken has two copie of the pea comb gene, larger if the chicken has just one copy of the pea comb gene. The "larger" wattles are the size you would expect on a chicken with a single or rose comb, so not extra-large, just not extra-small.

Duplex comb (V or Buttercup):
V is dominant over Buttercup and over not-Duplex.
Two copies of the V comb gene make the comb smaller and change the shape of the nostrils, as compared with one copy, or Buttercup, or any other comb gene (pea also makes a comb smaller, but doesn't change the nostrils. V doesn't change the wattles.)
One copy of the V comb gene can make funny looking combs (sometimes like Buttercup, sometimes other shapes). V + Buttercup has the same effect as two V genes.
Two articles about those comb types:
https://pubmed.ncbi.nlm.nih.gov/2013691/
https://pubmed.ncbi.nlm.nih.gov/2013692/

I haven't had much luck finding information about combining either of the Duplex genes with rose or pea.

What would you get if you mix a hen with a pea comb and a roo with a single comb and vice versa?

A chicken that is pure for the pea comb gene, crossed with a chicken showing single comb, will give chicks with pea combs, the bigger/blobbier form that comes with just one copy of the pea comb gene. Some people call these a "modified pea comb" or a "heterozygous pea comb."

Crossing those chicks with a single-comb chicken will give chicks with single combs (half of chicks) and chicks with those heterozygous pea combs (other half of chicks.)

It doesn't matter which parent has which comb type, because none of the known comb genes are on the sex chromosomes.

Are there any other genetic traits that are associated with different comb types. Like health problems or being more hardy?

Fertility issue (rose comb, see @DarJones post, applies only to some chickens with rose combs)

Heat tolerance (the biggest combs are best at cooling the chicken in hot weather. Great big single combs are probably best, with the smallest pea and V combs being probably the worst.)

Frostbite (big single combs are most susceptible, small combs are less susceptible.)

Wattle size (two genes for pea comb will reduce wattle size, which reduces the chance of frostbite and just looks different-- better or worse depending on your personal preference.)

Breast ridge (mentioned above, under pea combs. It doesn't seem to bother the chicken, but some people care how it looks, especially when serving a whole roast chicken.)

Cavernous nostrils (V comb, 2 copies of the gene only, makes the nostrils a different shape: I don't know if it has any health effect, but it does look different-- some people may care, others may not. For examples, look at photos of Polish or Houdan chickens.)

I have chickens with rose, single, V, and pea combs. I would like to have mostly pea combs in future generations are any of these comb types more dominant than a pea comb type. So should I not breed with some of these of I want mostly pea combs. I have a rooster with a pea comb and a rooster with a single comb if I use the rooster with the single comb will it make most of the chicks have single combs or are the other types more dominant?

If you want pea combs in future, the fastest path is to only breed from chickens with pea combs.

Do you care if you get walnut combs? That's pea + rose. If that doesn't bother you, feel free to use the rose comb birds in breeding too.

For any specific chicken that has traits you want, there are ways to breed with that chicken and end up with pea-combed offspring in future generations.

For the rooster with a single comb, if you breed him to single comb hens, all chicks will have single combs. If you breed him to hens with other comb types, the chicks may show the comb type of their mother, or they may have single combs anyway. Hens with a walnut comb could produce chicks with walnut, rose, pea, or single combs (depending on how many rose and pea genes the hen has.)

I know this is a lot. Sorry I just don't know much about comb genetics and I know that a lot of you are very knowledgeable about stuff like this.

Um, looking at the length of my post, I guess I do have a lot to say about it
I think I repeated myself in a few places, but I don't care enough to go back and edit much. Hopefully I didn't make any actual mistakes, or that someone else catches me if I did.

 

[CHICKENX2005]

Cushion and Strawberry are types of walnut comb. By that I mean that pages about genetics calls them walnut comb because they have both the pea comb gene and the rose comb gene. The people writing the official descriptions for chicken breeds, before the genetics were understood, named the comb types according to what they looked like.

Buttercup and V are caused by different alleles at a third locus (Duplex), different than pea or rose. The Duplex locus has at least three alleles (V, Buttercup, and whatever you call the normal one that is recessive to both.)


But the comb type we call "single" requires a specific allele at one locus (the pea comb locus) AND a second locus (the rose comb locus) AND a third locus (the Duplex locus).

So I would say single comb is not-pea, not-rose, and not-duplex as a way to express that it requires the recessive at all three loci.


Pea comb is caused by a dominant gene.
Rose comb is caused by a different dominant gene.
Duplex comb (V or Buttercup) is caused by a dominant gene that is different yet.
Each of those genes is at a different place on the chicken's chromosomes, so the chicken can have them in any combination.

Single comb is recessive to all of them. It needs the recessive not-pea gene, and the recessive not-rose gene, and the recessive not-duplex gene.
Breeding two chickens with single combs will give chicks with single combs, nothing else.

The rose comb gene is completely dominant. If you see a chicken with a rose comb, you cannot tell whether it has one or two genes for rose comb, because it looks the same either way. That, plus the fertility issue mentioned by @DarJones , is why single combs pop up sometimes in rose comb breeds (you can't spot who is carrying the not-rose gene and cull them, and the roosters that are split for rose and not-rose sire more than their fair share of the offspring.)

The pea comb gene is considered incompletely dominant. A chicken with one copy of the gene has a comb that looks different than a single comb: points are less tall, comb is thicker, may have an extra ridge on each side or bumps on each side, may look blobby and hard to describe. Occasionally fools people either way: either by looking almost exactly like a single comb, or by looking almost exactly like the pea comb of a chicken that has two copies of the gene.

A chicken with two copies of the pea comb gene has a smaller comb, and smaller wattles, and a strip of skin along the breastbone that looks a little funny and doesn't grow feathers. The smaller comb and wattles are good in cold climates. The skin difference doesn't really matter because they usually have plenty of feathers to keep warm anyway, but it looks a little different if you are serving a roasted chicken for dinner (some people care, some don't, but I have read that is why the pea comb of purebred Cornish chickens was bred out of the stock that produce modern Cornish-Cross meat chickens).
https://www.sciencedirect.com/science/article/pii/S0032579119489530
^This is one article that mentions the "breast ridge" on the skin of pea combed chickens.

Rose + pea makes a walnut comb. The chicken can have one rose comb gene or two, and it will look the same either way. The walnut comb and the wattles are smaller if the chicken has two copie of the pea comb gene, larger if the chicken has just one copy of the pea comb gene. The "larger" wattles are the size you would expect on a chicken with a single or rose comb, so not extra-large, just not extra-small.

Duplex comb (V or Buttercup):
V is dominant over Buttercup and over not-Duplex.
Two copies of the V comb gene make the comb smaller and change the shape of the nostrils, as compared with one copy, or Buttercup, or any other comb gene (pea also makes a comb smaller, but doesn't change the nostrils. V doesn't change the wattles.)
One copy of the V comb gene can make funny looking combs (sometimes like Buttercup, sometimes other shapes). V + Buttercup has the same effect as two V genes.
Two articles about those comb types:
https://pubmed.ncbi.nlm.nih.gov/2013691/
https://pubmed.ncbi.nlm.nih.gov/2013692/

I haven't had much luck finding information about combining either of the Duplex genes with rose or pea.


A chicken that is pure for the pea comb gene, crossed with a chicken showing single comb, will give chicks with pea combs, the bigger/blobbier form that comes with just one copy of the pea comb gene. Some people call these a "modified pea comb" or a "heterozygous pea comb."

Crossing those chicks with a single-comb chicken will give chicks with single combs (half of chicks) and chicks with those heterozygous pea combs (other half of chicks.)

It doesn't matter which parent has which comb type, because none of the known comb genes are on the sex chromosomes.


Fertility issue (rose comb, see @DarJones post, applies only to some chickens with rose combs)

Heat tolerance (the biggest combs are best at cooling the chicken in hot weather. Great big single combs are probably best, with the smallest pea and V combs being probably the worst.)

Frostbite (big single combs are most susceptible, small combs are less susceptible.)

Wattle size (two genes for pea comb will reduce wattle size, which reduces the chance of frostbite and just looks different-- better or worse depending on your personal preference.)

Breast ridge (mentioned above, under pea combs. It doesn't seem to bother the chicken, but some people care how it looks, especially when serving a whole roast chicken.)

Cavernous nostrils (V comb, 2 copies of the gene only, makes the nostrils a different shape: I don't know if it has any health effect, but it does look different-- some people may care, others may not. For examples, look at photos of Polish or Houdan chickens.)


If you want pea combs in future, the fastest path is to only breed from chickens with pea combs.

Do you care if you get walnut combs? That's pea + rose. If that doesn't bother you, feel free to use the rose comb birds in breeding too.

For any specific chicken that has traits you want, there are ways to breed with that chicken and end up with pea-combed offspring in future generations.

For the rooster with a single comb, if you breed him to single comb hens, all chicks will have single combs. If you breed him to hens with other comb types, the chicks may show the comb type of their mother, or they may have single combs anyway. Hens with a walnut comb could produce chicks with walnut, rose, pea, or single combs (depending on how many rose and pea genes the hen has.)


Um, looking at the length of my post, I guess I do have a lot to say about it
I think I repeated myself in a few places, but I don't care enough to go back and edit much. Hopefully I didn't make any actual mistakes, or that someone else catches me if I did.

Thank you

 

[phasianidae]

Duplex combsxany other comb will create a double version of that comb type.

This is not correct. The Dv allele is highly variable depending on it's regulation and what modifiers it is paired with. The expression of homozygous Dv ranges from a complete lack of comb to large horns with the equivalent mass of a single comb. As such, when the allele is paired with either rose, pea, or both, the expression can be equally variable and more because of the added variability of the additional allele(s).