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Discussion in 'Exhibition, Genetics, & Breeding to the SOP' started by metal-angel69, Feb 19, 2019.
Is there a visual difference between Mh/Mh and Mh/mh on e+?
Will the same apply for eb?
I would assume that there is because they do look different on wheaten, and because we had a mahogany duckwing oegb that never produced chicks quite as dark as he was with the gold hens.
But that was years ago, and my recollections are vague, so I'll tag @nicalandia, @Sneebsey, @The Moonshiner.
Whilst Mh is a dominant gene, I agree with @sylviethecochin that there are very slight phenotypical differences between a bird pure for the gene and one impure for it. They'll both be red, sure, but a double-factor bird is going to have a darker tone by virtue of the extra dose of Mh, though it could be too slight to notice. As Sylvie says above, if it works on one e-series it'll work on the other; Mh enhances the pheomelanin, gold pigment; the e- genes just tell the pheo- and eu-melanin where to go.
I consider also that the effects of Mh can be enhanced further by continued breeding for richness in tone amongst birds pure for the gene. I've seen photos of fantastically dark RIR here on BYC before, though can't seem to find them now, unfortunately.
ETA: I just traipsed around the yard trying to get a picture of two particular birds, a mother and daughter, both eWh/eWh, Co/Co, together, but the best I could achieve was a lovely picture of a completely different bird with two red blurs alongside, so we'll scrap that idea. The aim was to illustrate the differences in the head and neck. I find that Mh/Mh birds have a darker head than those impure for the gene.
Interestingly enough, Mahogany was isolated from a self buff type(Buff Minorca, I have the same experience with buff cochins)
in my experience Mh is completely dominant to mh+, that means that Mh/mh+ is as strong as Mh/Mh, any perceived differences would be due to other genes that enhance or ihibit its expression on F1s. for example RIR are not that dark due to Mh alone.
Here is a very good read on the outstanding work of the renown team of Dr. John Albert Brumbaugh and Dr. Willard Fisher Hollander.
http://www.chickencolours.com/Genetics of Buff Brum&Holl.pdf
Some excerpts from: A study of the genetic control of black-red pigment patterns in the fowl.
Dr. J. A Brumbaugh:
The successful teacher teaches not only with his mind but also with his hands. The author wishes to express his deep appreciation to such a teacher - Dr. Willard F. Hollander.
LOL! I say the title and thought "Is someone seriously thinking about building a coop out of mahogany?!"
@nicalandia, thank you for the pdf there; interesting reading. I understand that RIR, like any self-buff or red bird must have something other than Co restricting black pigment, but what could darken the pheomelanin but Mh? Ginger is a restrictor, like Co, with little effect on the depth of tone (as seen in Ginger game birds I have seen here), whilst Champagne Blonde and Dilute would actively inhibit the expression of pheomelanin.
The two birds to which I refer above are red colombian, rather than self-red. I have noticed similar in ER Birchen Marans mix birds. As you say, this could be caused by another gene, though I can't imagine what. I note that it is only tangible in females.
I understand that due to the richness of the dark mahogany of SQ RIR, it would appear that they are "self Red"(like self red leghorns), but they are actually just very dark black tailed reds(going by the SOP, males that show a red columbian pattern with dark/green sheen on neck will get deducted 3-5 points)
As to what makes them so dark? other red enhancers that enhance the effect of mahogany, for example autosomal red, and possibly others that have not been documented, some people have segregate eb instead of Wheaten.
further research on self buff breeds have confirm that the Ginger restrictor found on buff minorcas is actually Columbian, so the restrictor that Brumbaugh and Hollander found can be said without any doubt that is Co. but not to be confused about the phenotype called Ginger on OEG they are based on Db instead of Co.
on the difference shades of self gold birds(self lemon, self buff, self red) and a possible self white/silver.
The different shades of lemon/buff is due to diluters and enhancers, some say that the very light colored buffs/lemon lack mahogany, that could be true, but from my experience this is not the case, these very light birds had other diluters like Dominant white(as it will be shown by the experiments of renowned Danne Honour) and Blue/Splash(this was found on my line of Chochins), Danne Honour breeder of some of the best buff leghorns has advocated for many years the cross of dark buff lines with these type of too light colored buff leghorns, to keep whats causing these lemon colored buffs in check in this case dominant white in heterozygous form as confirm by the buff leghorn used on the experiment(the rooster has very good coloration, not too rich and not light at all)
For reference here I post the experiments carried by Danne Honour(On creating Buff long tails, the page has long been taken down, but with the help of the wayback machine we can all learn) http://web.archive.org/web/20060208033027/http://www.panopliageneticus.com/testmatingwheaten.html
Self reds IMHO(have not worked with them) lack any pheomelanin and eumelanin diluter(like Dilute or Champagne blonde).
Red Leghorns from Europe:
as for Self White/Silver? Entirely possible to create a self silver phenotype by using the same gentoype of self buff birds but exchanging s+ with S(Sex linked Silver)
Funny you mention the self-white. I had some end-of-lay hens from an egg-farm once that were just that. I had thought them extended black dom white at first, but they bred as silver Colombian wheaten with dom white. I thought it strange that they were there at all, honestly, as various forms of rsl are used in the vast majority of egg-farms here.
The tangent and links on buff are again of interest; I had a line of buff orps way back when which had dom white, but I hadn't considered blue/splash.
Apologies for the confusion regarding Ginger; I had assumed we were discussing Db Ginger, with the Gr abbreviation used in the paper being an alternate or archaic form.