Originally Posted by ChicKat
Originally Posted by dretd
Definitely time for all the Sherlocks out there to put their Thinking Deerstalkers on and come up with some other ideas!
Hi Dr ETD - nice to see you on the BYC forum.
- Hatched April 10th.
- Epistasis is a phenomenon that consists of the effect of one gene being dependent on the presence of one or more 'modifier genes' (genetic background). Similarly, epistatic mutations have different effects in combination than individually. Could be going on with some other recessives in CL that we don't know about -- I think I did point to that in my original post, not sure that they even know all the recessives for black...
- I'll quote your quote and raise you 5
It appears that Ml is an (incompletely) dominant trait and you shouldn't see that much amplification of the trait with two copies, certainly not enough for it to be hidden with one copy anyway. If you go to http://www.edelras.nl/chickengenetics/mutations1.html they talk about the different genes especially with regard to down color. Here is an excerpt from the talk on Ml (I am bolding the parts I think are most relevant):
"First described by Moore and Smyth (1971), after extracting it from a random breeding recessive white population previously described by Jeffrey (1947). Ml is incompletely dominant autosomal mutation that extends eumelanin into the normally red areas of pyle-zoned fowl, while having little effect on the chick down colour. Heterozygotes on wild-type (e+) or brown (eb) backgrounds are distinctly darker, particularly in the hackle and head; however, Ml/ml+ has little effect on eWh/eWh females. Homozygotes approach self blackness, but the salmon pigment of the wildtype and wheaten females remain evident. *
- • Ml found in the Quail pattern (Campo and Oronzco, 1986)
- • The Melanotic gene by itself does not make a wild-type bird black." <---- as we often interpret things differently -- the gene by itself -- meaning less than one copy?
This chick is a homozygote
and does express what almost looks like self-black. With really careful examination - I can see vestigal chipmunk stripes -- and I suspect adult plumage will display a salmon breast.. There could be epistatic action -- and I will go to Classroom in the coop and post her for the gurus there.... as time will permit.
Absolutely some epistasis may be going on. I am sure there are all sorts of influences going on in this breed including something dampening the expression of the cresting gene but that's another conversation!
The way I interpret the 'red' quote is that the homozygous reference was to adult plumage with the salmon breast still apparent. The chick you are showing us is still in the downy state where the reference says the wild type down is still apparent. I was thinking that it would be closer to the chick I showed with the blackish dorsal stripe. The pictures I've seen of Brassy Backs look more wild type. I was thinking more like your bird might be some crazy recessive black instead of a dominant trait, especially since your parents don't appear overly melanized.
I can't wait to see how she feathers out! In theory, if she is homozygous for Ml, she will be Brown-grey enhanced with the black melanin but will also be barred. How much of an influence will that black have? If it is near complete but she is barred, would she look more like a cuckoo marans with a semi-salmon breast than a cream Legbar?
This is quite a puzzle. I hope you do continue to post as she matures. I also would love it if you could post a link to the coop conversation if you start a thread in her. If you have it in your flock it stands to reason other folks have it in theirs so it would be awesome to be able to tell other breeders what it is.