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#98206 - 08/07/11 11:22 PM Re: ey revisited [Re: Muffi]
Henk69 Offline
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Originally Posted By: Muffi
Originally Posted By: Marvin
I dont know if my hen carries eWh or ey now... Why? because her eb looking boy is showing signs of Melanotic... and eb was thought to be recessive to ewh...


I thought that eWh was dominant to eb except in the presence of melanizers, then eWh is the most recessive e-allele.


That would be true if a pure wheaten can not be melanized in the same way. The melanizer mimics the effect of the other e allele i.m.o. (adding black pattern to the body).

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#102006 - 02/07/12 05:25 PM Re: ey revisited [Re: Henk69]
Wieslaw Offline
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Htul, I have at last found the description of recessive wheaten chicks. It is in this document:

http://jhered.oxfordjournals.org/content/74/1/43

I had downloaded it before it was 'closed'. It says that ''The ey/ey chicks are cream colored with a small head spot and/or narrow
dark back stripes''

PS. It is exactly what the chicks of the Spanish breed Murciana look like. I recall posting a photo of them in another thread.


Edited by Wieslaw (02/08/12 02:55 AM)
Edit Reason: added PS

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#102021 - 02/08/12 04:21 PM Re: ey revisited [Re: Wieslaw]
Htul Offline
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Many thanks for that Wieslaw.

I've also found the following from Smyth (1976) (halfway down on pg 74 - there are also some line drawings on the previous page)

"ey - The recessive wheaten down resembles that of the dominant allele "(e_wh), however, head spots and faint back striping are more common in the ey/e Y chick"

-consistent with the extract from Campo and Orozco that you've put up (but that would make sense - given that Campo's ey line was sourced directly from Smyth)

Yes, I agree this description does fit with the Murciana pic that you posted (but where to get a Murciana from ?....)

But I also recall looking for chick down images of Murcianas - and at least some such as this one



from http://www.gallinamurciana.org/gallinamu...8&Itemid=34 are the more conventional down pattern to be expected in classic eWh chicks (so there's no guarantee that even if you could get hold of Murcianas, that they would necessarily give chicks like the ones you put up previously)

I think this is actually an important point that is frequently overlooked - it's no good saying "Breed X is eWh based" or "Breed Y is E based" etc - because the same phenotype can so easily (in many cases) be made with differing E bases. You have to consider subpopulations that you sample from (Smyth's eb and ey lines are different in that they were specifically bred for that purpose)


Edited by Htul (02/08/12 04:34 PM)
Edit Reason: Added comments on typical wheaten down in Murciana chicks

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#102200 - 02/14/12 06:03 PM Re: ey revisited [Re: Htul]
Wieslaw Offline
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This is from Morjohn:

Quote:
The author (1953) described a recessive mutation (yellowish –white down) discovered in a red jungle fowl cock os Siamese origin. The effects of this gene were to dilute the down of chicks of both sexes to a yellowish-white and to depigment or dilute the plumage of juvenile and adult hens to creamy-buff or cinnamon. Adult cock were not affected and were indistinguishable from normal wild type cocks. The gene was completely recessive, and in adult cocks homozygous for the gene, the undercolor of the plumage was not affected


Just to show that cocks are different too: in the colour of underfluff.

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#102363 - 02/22/12 12:17 AM Re: ey revisited [Re: Wieslaw]
Terry Offline
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Registered: 02/19/12
Posts: 47
Loc: Qld Australia
I have just read through this thread and previous link from a few years back.
Previously KazJaps said:
"I find it strange that the hypothesis hasn’t been entertained that a single wheaten allele, plus a eumelanin restricting modifier is the difference between eWh & ey phenotypes/inheritance modes. I.e, only one wheaten allele was sequenced – it could be in theory a ey phenotype/inheritance mode allele, but the eWh phenotype/inheritance mode could be the result of the presence of a very closely linked eumelanin-restricting modifier (lol, yeh, messing with your heads) ."

And I must say I dont understand why this is not considered to be the truth. Every example given of a dominant Wheaten allele involves the presence of Mh, DB, Co or other melanin reducer or phaeoemelanin enhancer. All would make E+ specimens appear wheaten like. And I dont think it needs to be linked to E to give the appearance of dominance in the Wheaten allele.

However, in virtually every instance of allelic series in avian species, the real relationship between alleles is one of incomplete dominance. Pure dominance is rare because both alleles are always expressing and the gene product becomes a blend of both alleles. Therefore the debate might be simply one of semantics. In which case I would place Wheaten at the end of the series as it represents the 'opposite' expression for the E locus compared to the E allele.

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#102370 - 02/22/12 02:29 AM Re: ey revisited [Re: Terry]
Henk69 Offline
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Originally Posted By: Terry
And I must say I dont understand why this is not considered to be the truth. Every example given of a dominant Wheaten allele involves the presence of Mh, DB, Co or other melanin reducer or phaeoemelanin enhancer. All would make E+ specimens appear wheaten like. And I dont think it needs to be linked to E to give the appearance of dominance in the Wheaten allele.


x2

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#102371 - 02/22/12 03:10 AM Re: ey revisited [Re: Terry]
Wieslaw Offline
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Originally Posted By: Terry
And I must say I dont understand why this is not considered to be the truth


I understand it perfectly. There has been so many truths in the course of time and they have fallen one by one. Either pure fabrication, lacking documentation, lacking description how, impossible to reproduce, no pictures,wrong conclusions, or simply wrong identification. If this is not a truth, then it implies that Morejohn and the Spanish guys and Massachusets University were simply lying. Which does not make the things more trustworthy. Are you trying to say that pure eWh does not exist and it has never been examined for dominance?

I would turn your sentence around and ask: why should something be accepted as the truth when NOTHING about it has been really examined???



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#102373 - 02/22/12 04:24 AM Re: ey revisited [Re: Wieslaw]
SilverSilkie Offline
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Registered: 12/05/11
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One chicken (and his genotype) is not the other (and his genotype) I suppose !!

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#102374 - 02/22/12 04:31 AM Re: ey revisited [Re: Wieslaw]
Htul Offline
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Registered: 03/02/07
Posts: 495
Loc: Australia
Originally Posted By: Wieslaw
I would turn your sentence around and ask: why should something be accepted as the truth when NOTHING about it has been really examined???




X2 wink

Terry: the quote you allude to is out of context from the wider argument that Kazjaps was making: that the oft-quoted "Reeder hypothesis" about the mode of inheritance of "ey" vs eWh relies on the presence or absence of "recessive melanisers". Kazjaps' point was that none of the published researchers in that field made any such claim for these modifiers to be "recessive" as was stipulated by Reeder.

Hence, the immediately preceeding lines:

"I.e. none of these poultry scientists (Carefoot, Okimoto and Smyth) have stated a “recessive eumelaniser(s)’ was responsible for the two eWh & ey phenotypes/inheritance modes, only indicated that modifiers of eumelanin expression may be responsible.

These modifiers could be eumelanin restrictor(s) and/or eumelanin enhancer(s). "


are critical for providing context to that statement.

Further, (with all due respect to Kazjaps) it is actually not correct to say that "the hypothesis hasn’t been entertained that a single wheaten allele, plus a eumelanin restricting modifier is the difference between eWh & ey phenotypes/inheritance modes" (NB also Kazjaps' careful choice of the word "hypothesis" - and avoidance of suggestion that this is any way an 'absolute truth') : Smyth, in his claim that, in his experience, there were two separate wheaten alleles (in Crawford's PB&G pg 116) also added the disclaimer:

"However, consistent results using both eWh and ey by the author indicate that either two separate alleles do exist or that a single wheaten gene is very closely linked to a modifier of eumelanic expression".

The major point made though (as has previously also been made by Kazjaps) is that none of these later studies have focused on stocks DEFINED as ey (eg. Smyth's or Morejohn's ey) or even from stocks shown from test-crossing to behave as recessive wheaten: only use of breeds (and not even the same stocks of those breeds) where "ey" had previously been extracted by previous researchers.


Edited by Htul (02/22/12 04:36 AM)

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#102399 - 02/22/12 10:25 PM Re: ey revisited [Re: Wieslaw]
Terry Offline
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Registered: 02/19/12
Posts: 47
Loc: Qld Australia
Wieslaw
I am not saying any researchers are lying, but every observation made is done so from one's own perspective. I have read lots of papers, but cannot find or gain access to any that show specific research on the dominant Wheaten. Morejohn's papers focus on ey with no investigation of eWh although he mentions it. The Spanish papers I have found are only abstracts so I cannot read the details, but they appear to focus on breeds carrying Co. The same goes for various breeds quoted by Smyth as carrying eWh.
Obviously I would need to read the specific results of any papers on eWh by these people to see how far they went to remove other genes which would impact phenotype.
But with the work that has now been done on MC1R which has found only on wheaten allele, combined with the realisation that all these alleles are probably incompletely dominant to some degree, it becomes a matter of perspective as to how you classify the wheaten allele.

Personally I have Wheaten Modern bantams and they have always behaved recessive to eb in my yard. My Light Sussex mated to Columbian Wyandotte produce an intermediate phenotype, but obviously the presence of Co is confusing the picture.
Mating Light Sussex (eWh/eWh, S/-, Co/Co) to Silver Grey Dorking (E+/E+, S/-) produced the attached photo which is closer to E+ than to eWh
in my mind


So my Wheaten birds behave towards the recessive

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