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#117484 - 10/26/19 05:09 PM White Crested genetics in Polish
PurpleSully Offline
Feather

Registered: 04/19/18
Posts: 29
Loc: United States
I am interested in learning more about the genes that produce a white crest on black Polish chickens. I have a pullet that is half white crested blue but her crest is solid black. I bred her to my white crested black and all five of the offspring have a white crest. How does the crest gene (or allele) inherit? Is it a simple recessive? Are there multiple genes at work together? Also, I heard recently that the white crest is an allele of mottle. Is this true? Can you please tell me more about that?

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#117485 - 10/26/19 06:52 PM Re: White Crested genetics in Polish [Re: PurpleSully]
Marvin Offline
Lord of the Fowl

Registered: 11/23/06
Posts: 2010
Loc: Nicaragua
I Am nicalandia @backyard chickens forum, I am the one proposing that the white crest is a simple recessive allelic mutation of the mottling allele, the chick down seems to confirm it. It would not be a surprice since that allele has many mutations(white mottling, japanese mottling, european mottling and d'Uccle mottling)

Here is the link of muy post https://www.backyardchickens.com/threads/white-crested-black-polish-question.1331480/


Edited by Marvin (10/26/19 07:06 PM)

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#117486 - 10/27/19 08:53 AM Re: White Crested genetics in Polish [Re: Marvin]
Wieslaw Offline
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Classroom Professor

Registered: 09/18/09
Posts: 3872
Loc: Denmark
To me, the white crest is the biggest mystery of them all. Logically the crest should have the same color as the head without the crest, but the color does not show without the crest, at least I have not seen such thing.

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#117487 - 10/27/19 09:45 AM Re: White Crested genetics in Polish [Re: Wieslaw]
Marvin Offline
Lord of the Fowl

Registered: 11/23/06
Posts: 2010
Loc: Nicaragua
Originally Posted By: Wieslaw
To me, the white crest is the biggest mystery of them all. Logically the crest should have the same color as the head without the crest, but the color does not show without the crest, at least I have not seen such thing.
it does shows at least in the F2s without crest, it is shown on the chick´s down but as they grow since they lack a crest the head is solid black as full adults.

From research: https://academic.oup.com/ps/article/88/9/1811/1537609

"However, in this cross, the white crest contributed by the male founder individual masked the head streak phenotype. For this reason, phenotypes were collected on the F2 progeny at 12 wk of age as third generation feathers displaying the adult feather pattern replaced solid-colored juvenile feathers. "

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#117488 - 10/28/19 08:37 AM Re: White Crested genetics in Polish [Re: Marvin]
PurpleSully Offline
Feather

Registered: 04/19/18
Posts: 29
Loc: United States
Thank you, Marvin. I read what you wrote and added a comment with some examples for you. Thank you for the link. Interesting theory.


Edited by PurpleSully (10/28/19 08:54 AM)

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#117489 - 10/28/19 09:14 AM Re: White Crested genetics in Polish [Re: PurpleSully]
PurpleSully Offline
Feather

Registered: 04/19/18
Posts: 29
Loc: United States
In my post on that forum I included examples of offspring from a white crested black polish hen that I suspected was carrying mottle. I bred the hen to a tolbunt male to test my suspicions. Some offspring hatched with mottle, and some did not. It was a small hatch, but the results were roughly 50% of each. This confirmed my suspicion that the hen had one allele of the mottle gene. All offspring had a white crest. The Tolbunt that I used for test breeding was bought directly from a line that was created using only gold laced polish and Russian Orloff chickens. There was no Houdan in the bloodline, so the tolbunt contributor did not have the gene for a white crest. This means that the white crest on all of the offspring came from the white crested black parent. This confuses me because any other mix I've done or seen that only had one white crested parent did not result in a white crest.
If the white crest was a recessive allele of mottle, wouldn't the offspring need this particular allele from both parents to express? And how can both mottle AND white crest express on the same bird of they are alleles of each other? Mottle is recessive and must have two copies to express, but if the white crest is an allele of mottle, then a chicken with a white crest would only be able to have one mottle gene, and thus mottle shouldn't express mottle on the body.

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#117491 - 11/10/19 02:13 PM Re: White Crested genetics in Polish [Re: PurpleSully]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2906
Loc: Australia
In Carefoot's book, he mentioned that white crest had been found as incomplete dominant. I don't have my books and papers handy, but if I did I would look up Somes as a source.

Yes PurpleSully, as chickens are diploid animals, there is only a choice between 2 alleles at each locus. If white crest was an allele of the mo locus, a bird probably wouldn't be both mottled and white-crested, unless the 2 mutation alleles were co-dominant to each other. So then you would need to rely on test breeding results.


Edited by KazJaps (11/10/19 02:31 PM)

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#117492 - 11/10/19 03:24 PM Re: White Crested genetics in Polish [Re: KazJaps]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2906
Loc: Australia
Originally Posted By: KazJaps


Yes PurpleSully, as chickens are diploid animals, there is only a choice between 2 alleles at each locus. If white crest was an allele of the mo locus, a bird probably wouldn't be both mottled and white-crested, unless the 2 mutation alleles were co-dominant to each other. So then you would need to rely on test breeding results.


So your results in this post,
https://www.backyardchickens.com/threads...3#post-21885418

WCB x Tolbunt, all F1 white-crested, some mottled, some non-mottled. All offspring have a mo allele from the father.
Therefore this indicates that white-crest is not an allele of the Mo locus. There could only be 3 theoretical phenotypes, mo/mo (mottled only), mo^wc/mo^wc (white-crested only) and mo/mo^wc white-crested mottled.
As all your F1 would be theoretically mo/mo^wc (including the mother), it means there shouldn't be 2 different F1 phenotypes.

Unless (a very long shot), there are 2 different mo phenotype alleles segregating, and only 1 mo allele is co-dominant with mo^wc allele, the second mo allele recessive to mo^wc (as with the mother).

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#117493 - 11/10/19 04:04 PM Re: White Crested genetics in Polish [Re: KazJaps]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2906
Loc: Australia
As the mother could only supply one of her mo locus alleles to each individual F1 offspring, and if theoretically mo^1/mo^wc (mo^1 allele completely recessive), it would mean all her offspring got her mo^wc allele, none got mo^1.
And that the Tolbunt father was mo^1/mo^2 (mo^2 expressing mottling when with mo^wc).

Getting to be a very long, long shot.

If bred a F1 white-crested black mottled hen back to Tolbunt father...

F1 WCBM hen mo^2/mo^wc
X father Tolbunt mo^1/mo^2 =
Offspring:
- mo^2/mo^1 mottled
- mo^2/mo^2 mottled
- mo^wc/mo^1 WCB
- mo^wc/mo^2 WCBM

So you wouldn't segregate any solid blacks.
* Note, it's important to be able to track individual alleles from specific birds, over the generations (why a single F1 back to a parent makes it easier).

*Unusual that you didn't segregate any F1 with partial eumelanin restriction from Tolbunt Db.



Edited by KazJaps (11/10/19 04:14 PM)

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#117494 - 11/10/19 04:36 PM Re: White Crested genetics in Polish [Re: KazJaps]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2906
Loc: Australia
F1 WCBM hen mo^2/mo^wc
X F1 WCBM brother mo^2/mo^wc =
Offspring:
- mo^2/mo^2 mottled
- mo^2/mo^wc WCBM (50%)
- mo^wc/mo^wc WCB

Then you have a source of mo^2/mo^2 mottled that should produce 100% WCBM if crossed to mo^wc/mo^wc WCB

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