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#117466 - 09/10/19 05:34 PM On Mottling and recent allelic mutations found
Marvin Offline
Lord of the Fowl

Registered: 11/23/06
Posts: 2010
Loc: Nicaragua
Due to recent genetic mapping of the mottling allele(Endothelin Receptor B2 or EDNRB2 ) research have been able to identify at least four allelic mutations of the recessive mottling gene,

Research work by Japanese team: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0086361 responsible for two mutation confirmation(mo^w and mo^j)

Research work by Blacksburg, Virginia Team: https://vtechworks.lib.vt.edu/bitstream/handle/10919/85397/Li_J_D_2017.pdf responsible for two mutations(mo/mo and mo^d/mo^d)

mo^w/mo^w = Breed: White Minohik - The most extreme of recessive mottling mutations, a solid white bird: Cys244Phe amino acid substitution in EDNRB2( the researchers have given the mutation the official nomenclature of mo^w so this take precedence over any other claims)

mo^j/m^j = Breeds: Mottled/Exchequer Japanese Chabo and in Mottled Japanese breeds Pekins: Arg332His amino acid substitution in EDNRB2(no official designation was given to the mutation by the research at thet time so I propose mo^j/mo^j for Japanese mottling)

mo/mo = recessive Mottling(breeds sequenced: Houdan, Speckled Sussex, Spangled OEG): Ala228Thr amino acid substitution in EDNRB2

mo^d/mo^d = Breed: Mille Fleur and Black Mottled D'uccle, the research found that no mutation was present and it was identical to the wildtype Mo+ allele, but they went ahead and speculated that it may be a different mutation on the EDNRB2 but on a non-coding region. non-coding DNA is often incorrectly referredjunk DNA (no official designation has been given to the mutation so I propose mo^d/mo^d for D'uccle)


mo^w Chick down: White Minohik(Wheaten based)
https://journals.plos.org/plosone/articl...ne.0086361.g001

mo^j chick down: Mottled Japanses Chabo
https://www.efowl.com/wp-content/uploads/2016/02/Mottled-Jap-Chick-Group-510x333.jpg

mo chick down: mottled OEG
https://www.feathersite.com/Poultry/Games/GameBantams/MottledOEGBtyChicks.JPEG

mo^d chick down: Black Mottled D'uccle:


Of all of the chick down the one that is the least affected by mottling is the Mottled D'uccle, The black/blue mottled D'uccle hatch just like regular black ones and with time they start showing their mottling, this is due to the fact that their mottling mutation is identical to Mo+(wildtype) on the encoding region of the allele.


Due to the remarkable resemblance to mottling, the research team did not rul out that D'uccle have a non-coding DNA muation on the EDNRB2 allele, but it may be not entirely improbably that its just a different mutation all together(with different allele location)

These birds are the result of a cross between bantam mottled cochin and mille fleur D'uccle, the result is E/eb, Co/co+ s+ mo/mo^d

https://www.backyardchickens.com/content/type/61/id/7301668/





Edited by Marvin (09/10/19 05:47 PM)

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#117467 - 09/13/19 05:46 AM Re: On Mottling and recent allelic mutations found [Re: Marvin]
dingsda Offline
Bantam

Registered: 09/07/14
Posts: 73
Loc: Germany
thanks for the review of recent research on mottling.

I'm tinking of all the breeds where D'Uccles where breed in to get a better mille de fleur pattern, or to introduce lemon mille de fleur and porcelain.

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#117469 - 09/20/19 12:56 AM Re: On Mottling and recent allelic mutations found [Re: dingsda]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2906
Loc: Australia
Thank you Marvin. A good summary.

With the following mottled Cochin bantam x Millefleur d'Uccle cross, do you know if the F1 eventually mottled up?
Quote:
These birds are the result of a cross between bantam mottled cochin and mille fleur D'uccle, the result is E/eb, Co/co+ s+ mo/mo^d

https://www.backyardchickens.com/content/type/61/id/7301668/

I had given Exchequer Jap bantams and Splash Millefleur d'Uccles to someone, they accidentally crossed, produced Blue Mottled with good mottled phenotype. So from this I would say the Jap allele was on the same locus as the d'Uccle allele (considering both mo locus alleles were recessive to Mo+).The Exchequer Japs were E or ER based (tested with eWh/eWh B.T.White hen) yet chick down was solid white/cream or white with a small pigment dot on the head. So these had the same allele or very similar allele to the Japanese research lines.

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#117472 - 09/28/19 06:04 AM Re: On Mottling and recent allelic mutations found [Re: KazJaps]
Marvin Offline
Lord of the Fowl

Registered: 11/23/06
Posts: 2010
Loc: Nicaragua
Originally Posted By: KazJaps
Do you know if the F1 eventually mottled up?
Sadly that was the only picture posted by the owner of those birds.


Originally Posted By: KazJaps
So from this I would say the Jap allele was on the same locus as the d'Uccle allele (considering both mo locus alleles were recessive to Mo+).The Exchequer Japs were E or ER based (tested with eWh/eWh B.T.White hen) yet chick down was solid white/cream or white with a small pigment dot on the head. So these had the same allele or very similar allele to the Japanese research lines.
Japs or Chabos have the recessive Japanese mottling mutation(at least from the chick down perspective) and yes the d'Uccle mutation would be on the same allele albeit different mutations that is not registered on the encoding regions, non-coding mutations can have a profound effects, for example the Sex linked Barring gene has two none-coding mutations that came first, then the consecutive missense were selected because they enhanced the effect.

Excerpt from: Sex-linked barring in chickens is controlled by the CDKN2A ⁄B tumour suppressor locus

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1755-148X.2010.00700.x

"We favour a scenario where an initial non-coding
mutation, SNP1, SNP2 or a combination of the two,
resulted in a visible phenotype, and that the two subsequent missense mutations were independently selected
because they enhanced the phenotypic effect. This suggests a model where either of the two missense mutations are required but may not be sufficient to cause
Sex-linked barring"


My take is that the d'Uccle mottling mutation is wildtype at the coding region(making it identical to Mo+), but it has at least one non-coding mutation that is giving it it's mottling appearance, I also suspect that all of the Mottling mutations(mo, mo^w, mo^j) that can be coded also have the same non-coding mutation(akin sex linked Barring with it's non-coding mutations and coding mutations)


Edited by Marvin (09/28/19 09:27 AM)

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#117473 - 10/05/19 02:16 AM Re: On Mottling and recent allelic mutations found [Re: Marvin]
Hebe Offline
Feather

Registered: 07/24/16
Posts: 39
Loc: UK
Marvin, thank you that is very interesting. Probably explains why only D'Uccles and closely related look the way they do. I have been trying to develop the pattern in Wyandottes, bred attractive birds but never got quite the pattern I wanted. Seems I should have started with D'Uccles then.

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#117498 - 11/23/19 11:04 AM Re: On Mottling and recent allelic mutations found [Re: Hebe]
Wieslaw Offline
Moderator
Classroom Professor

Registered: 09/18/09
Posts: 3873
Loc: Denmark
To make it complete: I would like to remind the experiment carried out by Serebrowsky (?) early in the last century. According to him he crossed mottled Houdan with mottled Orloffs, and the resulting offspring wasn't mottled. Never repeated.

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#117499 - 11/30/19 11:01 AM Re: On Mottling and recent allelic mutations found [Re: Wieslaw]
Hen-Gen Offline
Ruler of the Roost

Registered: 10/01/05
Posts: 1182
Loc: Island of Fetlar, Shetland
Thanks for that information, Wieslaw. This coming season Iím planning a Spangled Russian Orloff x Speckled Sussex mating (both are actually mottled). Can I reasonably assume the offspring will be mottled?


Edited by Hen-Gen (11/30/19 12:09 PM)
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