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#27269 - 01/22/03 08:03 AM Re: Which is dominant , straight comb or pea comb?
Anonymous
Unregistered


MonachzMan, single comb is recessive to all other comb types.

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#27270 - 01/22/03 12:49 PM Re: Which is dominant , straight comb or pea comb?
R. Okimoto Offline
Lord of the Fowl

Registered: 07/18/02
Posts: 1498
Loc: Arkansas
Oops, single comb is recessive to all other comb types except....Breda. Breda is considered to be no comb, but there are some bumps up there. From descriptions it sounds like something combined with duplex. Females are supposed to have two side by side papillae and that sounds like duplex to me.

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#27271 - 01/24/03 07:46 AM Re: Which is dominant , straight comb or pea comb?
Anonymous
Unregistered


You are so right. I thought of that after I posted. Is the sequence v-comb duplex (DV), buttercup duplex (DC), then non-duplex (d), then breda?

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#27272 - 01/24/03 08:08 AM Re: Which is dominant , straight comb or pea comb?
Anonymous
Unregistered


Aren't reduced wattles also associated with pea comb?

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#27273 - 01/25/03 03:17 AM Re: Which is dominant , straight comb or pea comb?
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2807
Loc: Australia
“single comb is recessive to all other comb types except....Breda.“

Different loci, recessives, so a good example of “Epistasis”, ie where one gene interferes with the expression of another ( epistasis ).

For example, d/d,r/r,p/p,bd/bd is genetically combless, suppressing single comb. A d/d,r/r,P/P,bd/bd bird is still combless, but suppressing pea comb, & so on.... That is, the Breda combless gene (bd), when homozygous, suppresses all other comb types, regardless of d, r & p loci. Similar to recessive white gene (c/c) suppressing all colour in plumage, regardless of all colour/pattern genes present.

* In Hutt, Genetics of the Fowl:
-“Strictly speaking, pea & rose are not dominant to single comb but epistatic to it. Single comb is “Hypostatic” to these two but epistatic to the combless type of the Breda (Hutt, p88)”

-“ In Breda males, two small papillae on each side of the median line back from the upper beak indicate the duplex condition, although the birds appear practically combless (p87)”

In Crawford, p194: Dv allele is dominant to the Dc allele. The wide cavernous nostrils are expressed with homozygosity for Dv allele but not Dv/d+. Also expressed with Dv/Dc, but only in association with Dv allele.

The Breda breed has the wide-open nostril trait ( chickenbreeds website-Breda fowl )

------------------------
The P gene: pea comb & breast ridge/reduced feather characteristics is a good example of “Pleiotropy” ie the effect of a single gene on more than one characteristic ( Pleiotropy )

* please correct any errors!!

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#27274 - 01/25/03 03:28 AM Re: Which is dominant , straight comb or pea comb?
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2807
Loc: Australia
I haven’t found any sections on wattle genetics in Crawford & Hutt. Has anyone else? Haven’t found any designated genes for wattles either.

The Belgian bearded breeds have reduced wattles, in both rose comb & single comb varieties. The Breda breed seems to have wattles, no comb ( Feathersite- Breda fowl ).

In Crawford, p195, is a picture of a pea comb bird with wattles.

Here are some results of crosses I’ve personally seen:
* Cornish (Indian Game), (ie pea combed/reduced wattles) cross to single comb/wattles produces pea comb, with small intermediate wattle size.
* Cornish (Indian Game) cross to single comb/reduced wattles produces pea comb with reduced wattles.

Wattle size seems to have incomplete dominant traits.
From the above, I'm guessing that reduced wattle trait is independant to comb type.

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#27275 - 01/25/03 07:21 AM Re: Which is dominant , straight comb or pea comb?
R. Okimoto Offline
Lord of the Fowl

Registered: 07/18/02
Posts: 1498
Loc: Arkansas
Genes that affect comb size usually affect wattle size. Pea comb and the most dominant duplex comb, reduce comb size and usually reduce wattle size, but there are other modifiers that affect wattle size. Muffs and Beards is a big one. It has a drastic affect on wattle size. There must also be other modifiers that are around because you see a lot of variation in wattle size for duplex and pea combed birds.

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#27276 - 01/26/03 06:48 AM Re: Which is dominant , straight comb or pea comb?
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2807
Loc: Australia
Thank you Ron.

So the combination of Mb/mb (beard/muff) & P/p, r/r (Pea comb) heterozygotes gives a reduced wattle phenotype similar to Mb/Mb, p/p. Whereas Mb/mb, p/p or mb/mb, P/p have small intermediate wattles. Although some P/P pea-combed breeds have small intermediate wattles, not reduced. When I say “reduced”, I mean “no wattles” or approx 1-3mm size.

Handy to know the correlation between Mb & wattle size. It should help when dealing with oversized wattles in d’Uccles. I was thinking there wasn’t a correlation as I’ve had a bearded (average size) roo, with larger (1cm) wattles, not coming from crossbreeding. It may have been a Mb/mb mum, therefore harder noticing intermediate wattle size. Although her beard is not bad either. I have some d’Uccle roosters with rather large combs for the breed. These have very small wattles, so I’m not sure if a correlation between comb size & wattle size with these.

Are you sure Ron that duplex (Dv) affects wattle size? Both Breda fowl & La Fleche have average to large sized wattles. Don’t non-bearded Polish have average size wattles? I’ve read where Bearded Polish have wide-open nostrils, suggesting Dv, but don’t know if non-bearded are the same. Don’t breed any of these myself, maybe you found a correlation when crossing Polish? Do the combless Polish have Breda combless gene (bd)?

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#27277 - 01/26/03 06:54 AM Re: Which is dominant , straight comb or pea comb?
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2807
Loc: Australia
Kaalnek, have you seen the Pea- comb Turken webpage at the following link?
David\'s Turkens

These are blue-egg laying, pea-combed Naked Necks. The photos of these show the neck feather tuff typical of heterozygous Na/na naked necks. Unfortunately the author doesn’t discuss this issue, so don’t know if Na/na or Na/Na, but they appear to be P/P homozygous for Pea Comb. He does mention that he believes these Turkens were hybrids between Naked Necks (single comb) & Araucanas. I was wondering, would a Mb/Mb (beard/muffs), Naked Neck (Na/Na) express a beard, ie does Na suppress Mb)?

The author noted 2 types of pea combs in his Turkens, one small pea comb, the other bulbous in roos & no comb in hens.

The author also mentions breeding blue-egg laying Silkies (Standard, but genetically walnut comb) & blue-egg laying naked neck Silkies. There was mention that one of his original Turken hens was carrying the silkie gene (h).

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#27278 - 01/26/03 08:54 AM Re: Which is dominant , straight comb or pea comb?
R. Okimoto Offline
Lord of the Fowl

Registered: 07/18/02
Posts: 1498
Loc: Arkansas
I don't know if the Mb and P reduction is additive in the sense that Mbmb+ Pp+ are equal to PP mb+mb+ and p+p+ MbMb.

There are a lot of genes that affect wattle size. The only reason that I think that duplex reduces wattle size is that I've never seen a duplex bird crested or not with wattles as large as a Leghorn. This could be due to other modifiers in the breeds that keep the wattles smaller. Leghorns have extra long wattles even for single combed birds and it probably isn't a fair comparison. My guess would be that since duplex reduces comb mass that it also reduces wattles. You always have the problems that other genes may be affecting the trait in the opposite direction.

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