Difficult! Silver wheaten questions for genetics experts!

[nicalandia]

In columbian restricted wheaten and silver birds, the body is silver because what would normally be black (wheaten on wheaten females) is converted to white. The columbian gene normally removes black and since the wheaten color is produced through a pathway that normally produces black, the columbian gene stops the production of the wheaten color. You have to think of the wheaten color as being converted from black.

Tim

never thought about it this way tim, but this is true for eb and e+ and ER with enough restrictors... en when you say what would be black is coverted to white is coverted to Silver right? because on gold based birds the black is turn to gold

 

[tadkerson]

A little more explanation.

According to Kimball, faverolle are dark wheaten and not light wheaten. He isolated the dark gene ( Dk*Dk) from slamon faverolle.

Wheaten is produced through a different pathway than gold. Wheaten uses the same pathway that produces black but the black pathway is altered by the low levels of tyrosine. Low levels of tyrosine switch the black (eumelanin) to a wheaten (pheomelanin) pathway. No tyrosine ( as in the silver/columbian pathway) produces no wheaten color. Gold is another completely different pathway for the production of red/buff etc. Even then the columbian gene alters this pathway some producing a different red color.

In the case of Db*Db or Co*Co, they alter the pathway of black by decreasing the amount of tyrosine available to make black- this shift in tyrosine favors red/buff/ etc. color production.

You are correct- when I say white I mean silver. In the salmon faverolles case, the white from the silver allele is decreasing the intensity of the wheaten color. If you add the columbian gene to the mix, then the pathway for black/ wheaten is switched off and you get a white(silver) body on a wheaten bird.

Tyrosine is the key to melanin production in chickens. Altering the tyrosine levels causes different pigment production.

Lots of tyrosine No tyrosine
Black ---------> red -----> buff----------> white

Not all white color is due to lack of tyrosine; white can be caused by other mechanisms. Recessive white is due to lack of tyrosine while dominant white is due to a different mechanism..


Tim

 

[tadkerson]

Do you have more about this?

Ling, M. K., Lagerström, M. C., Fredriksson, R., Okimoto, R., Mundy, N. I., Takeuchi, S., & Schiöth, H. B. (2003). Association of feather colour with constitutively active melanocortin 1 receptors in chicken. European Journal of Biochemistry, 270(7), 1441-1449.

http://inquiry.uark.edu/issues/v01/2000a10.pdf

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

Takeuchi, S., Suzuki, H., Yabuuchi, M., & Takahashi, S. (1996). A possible involvement of melanocortin 1-receptor in regulating feather color pigmentation in the chicken. Biochimica et Biophysica Acta (BBA)-Gene Structure and Expression, 1308(2), 164-168.


Brumbaugh, J. A. (1968). Ultrastructural differences between forming eumelanin and pheomelanin as revealed by the pink-eye mutation in the fowl.Developmental biology, 18(4), 375-390.


Takeuchi, S., Takahashi, S., Okimoto, R., Schiöth, H. B., & Boswell, T. (2003). Avian Melanocortin System: α‐MSH May Act as an Autocrine/Paracrine Hormone. Annals of the New York Academy of Sciences, 994(1), 366-372.

Have fun.

[FONT=Arial, sans-serif]The product of the E locus alleles is a form of a melanocortin 1 transmembrane protein. Different alleles produce a different transmembrane protein. The melanocortin system produces the basic plumage color pattern in a chicken. [/FONT]

[FONT=Arial, sans-serif]Tim[/FONT]

 

[nicalandia]

Ling, M. K., Lagerström, M. C., Fredriksson, R., Okimoto, R., Mundy, N. I., Takeuchi, S., & Schiöth, H. B. (2003). Association of feather colour with constitutively active melanocortin 1 receptors in chicken. European Journal of Biochemistry, 270(7), 1441-1449.

http://inquiry.uark.edu/issues/v01/2000a10.pdf

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

Takeuchi, S., Suzuki, H., Yabuuchi, M., & Takahashi, S. (1996). A possible involvement of melanocortin 1-receptor in regulating feather color pigmentation in the chicken. Biochimica et Biophysica Acta (BBA)-Gene Structure and Expression, 1308(2), 164-168.


Brumbaugh, J. A. (1968). Ultrastructural differences between forming eumelanin and pheomelanin as revealed by the pink-eye mutation in the fowl.Developmental biology, 18(4), 375-390.


Takeuchi, S., Takahashi, S., Okimoto, R., Schiöth, H. B., & Boswell, T. (2003). Avian Melanocortin System: α‐MSH May Act as an Autocrine/Paracrine Hormone. Annals of the New York Academy of Sciences, 994(1), 366-372.

Have fun.

[FONT=Arial, sans-serif]The product of the E locus alleles is a form of a melanocortin 1 transmembrane protein. Different alleles produce a different transmembrane protein. The melanocortin system produces the basic plumage color pattern in a chicken. [/FONT]

[FONT=Arial, sans-serif]Tim[/FONT]

love to read from the good Dr. Okimoto again, hey thanks for the info Tim

 

[smoothmule]

So interesting, not what I expected a Silver Wheaten hen to look like. But then, not so far off from some of the silver duckwing hens I've seen.

 

[nicalandia]

So interesting, not what I expected a Silver Wheaten hen to look like. But then, not so far off from some of the silver duckwing hens I've seen.

Silver Wheaten hens

 

[troyer]

In chickens the male coloration is the default color and the female color is due to the presence of estrogen in the skin. In other words the males color is not due to male hormones but due to the absence of female hormones. The basic plumage color wheaten is highly variable in females and I believe this is due to genes that are modifying the wheaten basic plumage color. It could also be a promoter that is different. And then you can have different combinations of a gene and a promoter. Lots of possibilities.

Take for example salmon faverolle, both the male and the female express red or wheaten in their plumage and they are silver wheaten. The wheaten color in the silver female would be black but the wheaten allele prevents the production of black on the body therefore the wheaten color stays. The wheaten color is due to the wheaten allele in the silver female. The gold allele enhances the wheaten color caused by the wheaten alelle ( remember black is converted to wheaten) when you remove the gold and replace it with silver the wheaten color stays and the silver fills in where the gold was located causing a reduction in wheaten color.

In columbian restricted wheaten and silver birds, the body is silver because what would normally be black (wheaten on wheaten females) is converted to white. The columbian gene normally removes black and since the wheaten color is produced through a pathway that normally produces black, the columbian gene stops the production of the wheaten color. You have to think of the wheaten color as being converted from black.

Tim

This is a cubalaya hen and we have not yet really figured out what her color is.
Is the colombian restricter, restricting the black and turning those areas silver?
This hen's parents were whites.



This is a blue breasted wheaten cock, 50% cubalaya, 25% standard dark cornish
and 25% golden sebright. This cock's sire was Blue Golden.



This wheaten cockerel is the result of breeding the blue breasted wheaten cock
and the above hen.



These pullets are full sisters to the above cockerel. 1st picture at 7 months and
2nd picture at 3 months of age. The pullet in the back is blue wheaten.


3 months of age. Beautiful little 'crow beaks'. These are not the same birds as
the 2 above, but full sisters to them.

 

[gallorojo]

Troyer, top hen is genetically Wheaten, (Wh,) plus one copy Dominant white, (Ii, ), which would make her the wheaten version of red pyle. Most red pyles are made on wildtype/duckwing (e), but you can make one on any BB Red type bird. She is also pure for mottled, (mo), so genetically, she is a mottled(spangled) wheaten pyle. Genetic terms and show./game terms are often not the same. Show or game people consider spangled to be white spots over colored background, and mottled to be white spots over black background. Genetically, they are one and the same. She is not columbian restricted, dominant white is what removed the black. Dom white only affects black, and leaved red/brown be. She is not a silver, she is a red, otherwise, all her sons would be golden duckwings. I suspect that hen is a very heavy melanized , almost black necked version of wheaten, like you see in some lines of asils, etc. Except the Dom white deletes all the black and makes it white.

The 7 month pullets, background one is a pyle wheaten, foreground, regular wheaten. They will be carrying mottling but not expressing it as they need 2 copies to show it, since it's recessive.

Young pullets-not sure what to say there. Hard to believe they are same birds as 7 month pullets? I can say for sure they are not silvers or columbian, impossible based on parent stock. Almost certainly are dominant white. Best guess is some interaction between mottled and dominant white plus maybe something else going on? A diluter of some sort maybe? Also could just be a phase young birds went through while growing that I am not familiar with and threw me off before. I've not had pyle pullets that looked quite like that before, so on those I am uncertain.

 

[gallorojo]

Also, since I began this thread, I have figured a lot out about genetics, but, I still don't know nearly everything. One thing I can say is there is still debate and uncertainly about some aspects of how wheaten interacts with other things. It's not as well studied or agreed upon as some other things. There is still no consensus on what exactly makes a cubalaya wheaten diffierent from a Marans wheaten. Lots of guesses, but notice how much debate any thread on wheaten genetics creates. See also this thread.--http://www.backyardchickens.com/t/553141/recessive-wheaten-question

I'm not sure anyone has the answers with some of the oriental breeds, exactly, all the time.

 

[troyer]

Sorry gallorojo I edited my post. In the first pullets picture the back one is blue wheaten and the bottom pictures are full sisters to the above 2.