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#93855 - 01/09/11 07:04 AM ey revisited
Htul Offline
Coop Keeper

Registered: 03/02/07
Posts: 495
Loc: Australia
Wieslaw's recent query re: wheaten and its apperance in the absence of other modifiers has rekindled my ponderings on eWh vs ey: and how this has sat somewhat uneasily with me

Most will say/quote/think something along the lines of "that's done and dusted: it's been conclusively proven and well accepted that there is no such thing as a separate eWh and ey - they are the same gene, but simply act either as a dominant or recessive in the presence/absence of melanisers"

To substantiate this view, most will then quote the work of Dr Ron Okimoto and/or Leif Andersson (from what I've been able to work out, essentially either Ling et al (2003) (+/- Dr Okimoto's direct posts here at The Coop) or Kerje et al (2003) respectively). Some will also cite Carefoot's earlier work in test breeding to demonstrate that this alternating gene behaviour is possible.

However, I feel that, to do so, is to possibly misinterprete what these researchers have found/claimed. Yes, there has been work to demonstrate that the melanocortin-1 receptor gene is what classical genetics has described as the E locus, and that the MC1R alleles from phenotypically wheaten chickens have been sequenced and in all cases, it appears that one wheaten allele has been involved (which, on the mode of inheritance, appears to be eWh). However this does not preclude the existence of another (or even several other) E-locus alleles that can produce a wheaten phenotype: including, but not limited to ey.

Certainly Dr Okimoto does not claim that "there is no such thing as a separate recessive wheaten allele." In fact, quite the contraty: he mentioned that (in "E locus order of dominance (again!) )

Originally Posted By: Ron O.
...
Recessive wheaten is a strange story, but Smyth has told me that he used to maintain a recessive wheaten line, and Morejohn had a Red Junglefowl line that segregated wheaten downed chicks from wild-type parents in 3:1.

There probably is a recessive wheaten somewhere. I found a Buff Rock line that segregates for a weird E locus allele that seems to be a double mutant. I got it from McMurray. It has the Fayoumi birchin mutation and the dominant wheaten mutation in the same gene. I don't know what the phenotype of such a bird would be like. The Fayoumi mutation would send signal all the time (produce black pigment) and the wheaten mutation would inhibit signal propagation. At least, that is the theory if wheaten is like red fur color in mammals.

....


From what I can ascertain, Andersson's group described E and not wheaten variants, and although Carefoot did postulate that there could be a single wheaten allele based on the results from a single hen which could, in different pairings, act either as a dominant or recessive wheaten, he did not state that this conclusively demonstrated that "there was no ey".

Kazjaps, in "Dominance of wheaten" give a very thorough and comprehensive review of the studies involving wheaten, and really, the only firm specific claim that the ey and eWh sequences are the same is made by Black Feather in Recent review of colour genetics

Originally Posted By: Black Feather
About eWh and ey, Gérard has written (2000) in the chapter about E (after translation) : "Carefoot (1981) suggests that the two alleles eWh and ey are only one, dominance or recessiveness are caused by interaction with other genes increasing or decreasing black."

In 2003, Kerje et al. have published a molecular proof that E locus is in fact the gene Mc1R (Melanocortin 1-receptor), as in mammals, with determination of sequences for alleles E, e+ and ebc.

In 2006, my lab has sequenced more alleles, including ey and ewh, and it seems that their coding sequences for Mc1R are not different.

S. Kerje, J. Lind, K. Schütz, P. Jensen, L. Andersson (2003)
Melanocortin 1-receptor (MC1R) mutations are associated with plumage colour in chicken
Animal Genetics 34 (4), 241–248


I, like Kazjaps am very interested in how the ey was sourced.

So, really, my questions are:

In the works that seem to be repeatedly cited as "proof there is no ey, only eWh", which breeds, and how many individual wheaten animals were sequenced?

Have any animals actually defined specifially as ey (eg. Morejohn's RJF or Smyth's recessive wheaten tester line) been sequenced? (I understand that these lines perhaps have been lost, but were skins/feathers of any of these birds ever saved: fancy things can now be done with archival DNA, theoretically this should be even easier with birds which have nucleated red blood cells).

Otherwise, it's not unlike if I(in Australia) were to go out to sample carnivores, in the hope of finding a grey wolf (not native to here), only to conclude that there are only dingos, and hence that "wolves" and "dingos" must be completely synonymous and that there are no such things as wolves, only dingos.

Cheers,
Htul

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#93862 - 01/09/11 10:35 AM Re: ey revisited [Re: Htul]
Wieslaw Offline
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Classroom Professor

Registered: 09/18/09
Posts: 3844
Loc: Denmark
You are not the only one who is a little sceptical. I think some of us (including me) have a smoldering suspicion, whether all the preparations before the actual experiments are always properly done . Unfortunately the history shows that it is not always the case.I have just read several publications on pubmed.gov,from not so long ago, 1990's and 2000´s. Authors of the publications provide 'bombproof' evidence and results for something, what turns out to be not true.
One of them here:
http://www.ncbi.nlm.nih.gov/pubmed/8467400

Now it is accepted that e-locus is on microchromosome 11, so no linkage.


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#93870 - 01/09/11 10:51 PM Re: ey revisited [Re: Wieslaw]
RuffEnuff Offline
Ruler of the Roost

Registered: 01/27/06
Posts: 1154
Loc: Australia
oh dear stirring up a hornets nest again.

i just wish this melanizer that was supposed to affect the way wheaten behaves were identified and we were given some sort of visual description of it so we could test the theory that way. i regularly cross wheatens and eb and regularly have been confounded by the results.

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#93872 - 01/10/11 05:01 AM Re: ey revisited [Re: RuffEnuff]
Htul Offline
Coop Keeper

Registered: 03/02/07
Posts: 495
Loc: Australia
Wieslaw: I agree, this is why most (good) scientists will avoid making the claim that their conclusions are "bombproof" - they otherwise look rather foolish if their claims are contradicted by subsequent research. Therefore, you generally find statements like "these results suggest" or "these results are consistent with" rather than "these results prove" in scientific papers.

Ruff: I think you know my posts a little too well - but always good to make us think more deeply about the things we take as fact. re: your wish for a visual desciption of these melanisers: unfortunately, if they are not so much 'melanisers' as 'modifiers' of gene expression, it may well be that, unless in conjunction with the very gene that they modify, their effects may not be phenotypically evident at all.

All, I must retract one of the statements I made earlier (lest I fall prey to the very thing that I suggest that we do not all do and misquote/misrepresent the conclusions of the aforementioned research). On re-reading Ling et al (2003), the footnote to Table 1 does indeed state: "Note that eWh and ey are identical in amino acid sequence".

Table 1 itself also lists "NHR, RIR, Buff Min(eWh)" as the line from which the allele was sequenced (though no further details are provided as to the further origin or numbers of individuals sequenced).

This, however, suggests to me that this analysis re: the identical nature of the amino acid sequence (note aa sequence and gene sequence identity are not the same thing: one is the protein sequence, one is the DNA sequence - though it is really the proteins that lead to what we see in the end) between ey and eWh is founded on the assumption that NHR and RIRs are ey and that Buff Minorcas are eWh? (at least based on the sidenotes that they have applied).

Perhaps this assumption is based on Brumbaugh and Hollander's (1966)description of buff (avaialable from here ) and the associated wheaten alleles.

On reading this, the paper suggests that RIR, Buff Minorcas and speckled sussex are all ey. However, when you read the study itself, the RIR and Buff Minorca crosses with RJF sound (at least to me) like they are actually behaving like eWh - the chick downs for these crosses are described as having "pale narrow striping" (however, these may be confounded by the other factors leading to 'buff'); whereas the description of the speckled sussex cross sounds more convincingly like it behaves as you would expect for ey. There is also mention of a specific ey tester line.

One very interesting point about this study is that it actually mentions the preservation of the skins from the study animals as a record. So, depending on whether or not these skins can be tracked down some 45 years later, it may well be possible to more conclusively determine if indeed ey (as defined by previous researchers) is identical to eWh (particularly if similar material can also be sourced from the RJF line described by Morejohn)

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#94109 - 01/22/11 07:03 AM Re: ey revisited [Re: Htul]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2871
Loc: Australia
I found a couple of old papers:

A GENE FOR YELLOWISH-WHITE DOWN IN THE RED JUNGLEFOWL
(G. VICTOR MOREJOHN)
http://jhered.oxfordjournals.org/content/44/2/47.full.pdf

*This one has photos of the ey wheaten mutant Red Jungle fowl (chicks & adults).
--------------------

WILD TYPE PLUMAGE PATTERN in the Fowl
(ELLIOT KIMBALL)
http://jhered.oxfordjournals.org/content/43/3/129.full.pdf

*This one has the Wh - wheaten test breeding, & many others.
(Note: there's the error in there that Kimball thought Columbian was an E locus allele (written as e).)

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#94304 - 02/03/11 05:24 PM Re: ey revisited [Re: KazJaps]
Wieslaw Offline
Moderator
Classroom Professor

Registered: 09/18/09
Posts: 3844
Loc: Denmark
In this document(scroll all the way down) :

http://www.inia.es/gcontrec/pub/CATALOGO_INIA_Gallinas_1290596384804.pdf

there is a picture of ey hens. As far as I guess from Spanish, they were imported from Massachusetts University in 1975

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#94309 - 02/04/11 12:16 AM Re: ey revisited [Re: Wieslaw]
Henk69 Offline
Moderator
Classroom Professor

Registered: 02/13/06
Posts: 3229
Loc: Netherlands
All these breeds inherited the bad tail gene?

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#94340 - 02/06/11 03:36 AM Re: ey revisited [Re: Henk69]
Sonoran Silkies Offline
Flock Leader

Registered: 10/09/08
Posts: 347
Loc: Arizona
Wow! Looks like they really had to work to select that many birds with ratty tails!

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#94341 - 02/06/11 03:53 AM Re: ey revisited [Re: Sonoran Silkies]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2871
Loc: Australia
Me thinks it's environmental - the Smyth ey line is not related to the Spanish Breeds.

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#94363 - 02/07/11 07:03 AM Re: ey revisited [Re: KazJaps]
Richard in MA Offline
Flock Leader

Registered: 01/23/07
Posts: 332
Loc: Massachusetts
How, specifically do you suspect environmental? It seems that even the birds pictured on open range have the frayed tails. It appears that the feathers lack something that helps hold them together. They all seem too consistenly poor to be attributed to cage fraying to me.

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