Muscovy genetic question

[ian4379]

my silver drake has a small white patch on his neck, if the ducklings turn out white i would presume that he has one dose of white and this has expressed itself in the neck OR as we've discussed in another forum rollyard it's possible it could be a recessive white gene. we'll have to wait and see!

regarding the black cap on the blue duck - some of my blue muscovy have black heads and near black chests, the barred birds have a more blue head so far with my stock.

 

[AquaEyes]

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Hmmm, but is this always the case, for example, Black Capped Whites? And how variably does hetero incomplete dominant white express?

I have not seen "black capped whites." Are you saying they are all white, except for color on top of the head? Could they possibly be homozygous for "real pied" and heterozygous for white? On the muscovy genetic calculator it seems possible to have this, though there is no picture for this combination (as well as many other combinations...argh). I've also noticed that some of the "real pied" images in different colors on there are also showing the white-head gene, but the image pops up without selecting that trait...oh, well, it's a work in progress, I suppose.

I'm thinking that the variability of dominant white is based on the random selection of activation of the chromosome. I'm not sure it applies in this case, but I know that in other organisms, some cells express the genes on one of the chromosome pair, while others express genes from the other of the pair. Whichever of the pair is "turned on" is set early in development, and each cell that descends from those that have been "set" will maintain which chromosome is active down the line. Thus the random pattern of white in split-whites -- the patch of white on the body represents a patch of cells that descended from cells that activated the chromosome with the white gene, and the colored portions originated from the cells that activated the other chromosome.

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Yes, maybe?

Oh, don't worry, it's pretty much a certainty...hahaha...I'm just applying what I know of how genes work to what I'm able to learn about how the colors and patterns work in muscovies. If I see something that isn't labeled correctly, it will affect my interpretation. And remember, I'm doing this without having birds of my own, so I have to scour MANY MANY sources and try to find the things that are held to be true among the most sources, and then compare them to how genetics works to see if it's REALLY true, and if not go back and figure it out. If I had my own birds, I could very easily be testing this and reporting my results.

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So how can this be? The solid or self silver drake shouldn't have the incompletely white gene (P) or dominant White Head (C) to pass onto progeny because if he did we should see some evidence of these factors in him shouldn't we? The duck looks pied patterned as a result of the recessive duclair (d) gene only (@ this stage & in later photo), but I guess could be hetero for P also? Even so, if the solid Silver drake hetero for d, no ducklings should be all/pure white should they! Unless.........!

You didn't copy the rest of the original post. It was said that it "looks like I may have hatched white ducklings" but continued that it could very well be that they are very light because of multiple dilution genes going on, and that we'll have to wait and see what color they turn out to be. I'm thinking that "looks to be white" means that the ducklings have yellow down, like the whites, but that they haven't feathered out yet.

The ducks "cap" looks black & that is interesting considering she has blue dilution?
The pictures of blues I've seen are all darker at the head anyway. I'm wondering if an "in-person" inspection of the head color would allow one to see that, while dark, it is still lighter than "true black" and thus falls within the range of color found on the tops of the heads of blues. It's just that with white right next to it, the "dark blue" might appear to be black. But, again, I'd have to have a better look to be sure.

 

[dianaross77]

I don't know about any other blue muscovy ducks but my drake is blue and while his head is quite a lot darker than his body, it is still blue. I imagine that from far away it could appear black but you can tell the difference when he's standing next to my black pied duck.

 

[AquaEyes]

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Thanks for the confirmation! This whole process would be so much easier for me if I actually had the birds in front of me.

hehehe

 

[AquaEyes]

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That is entirely possible. There are many species which exhibit two forms of "white" -- dominant and recessive. I don't know if it has been verified with Muscovies, but a test would be to breed the "recessive white" to a bird that is not white, and does not carry white. If it truly is a "recessive white" then all the offspring will be colored, with no white feathers. If it is the incomplete dominant white, then all the offspring will be colored, with random white feathers.

 

[rollyard]

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Years ago white birds with black caps (that didn't disappear post juvenile moult) used to be quite common here, & am told that they did breed true; all white with pigmented cap yes. I guess they could have been this colourform as a result of d/d, P/p+, but would there remain consistency of pattern if true breeding as reported, eg, what about the 25% homozygous for incomplete dom white bred from two heterozygotes?

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Yes, this makes sense to me, & could well explain the variabilty seen in this & other instances! However, depending on what you read (& see), some info suggests that hetero incomplete dominant white (P/p+) can produce haphazardly marked birds with large areas of white all over, while others confine "tighter" haphazard white markings to front of bird, eg, head, neck, & breast (the calculator for example). Maybe some of the really haphazard white birds seen are result of combinations of genes for white markings as I think you have previously mentioned, eg, P/p+, C/c+, d/d, & not hetero P/p+ alone? Selection pressure could alter pattern (amount of white) over generations?

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I agree, & not just for those factors that cause "no colour".

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Yes, because I was placing emphasis on the possibility of something other than multiple diluters doing the work, in the context of past communication with Ian

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Blues I have bred in the past with pigmented head exhibited same colour as rest of body from memory. As you say, it is likely that a close inspection could find that head is a very dark blue, or @ least not solid black, but I still find incongruence interesting. The odd feather leaking yes, but a whole patch?

Something else to consider re: the hetero for white marked bird which only expresses small amount of white on the neck for example; how to differentiate this from similar naturally occuring white in the wild-type bird (not due to P)?

Good points & observation AquaEyes

 

[AquaEyes]

Thanks! I'm trying....it's hard when I don't have actual birds in front of me, and try to draw conclusions based on what other people report and pictures they post.

Do you think the variable amount of white might have to do with maternal versus paternal inheritance of the white gene? I know that there are instances in other organisms where only the maternal (or paternal, depending on the instance) chromosome is the "active" one of the pair in the offspring. I've also read about "preferences" that aren't exactly one or the other, but that organisms develop with more cells with mom's chromosome being active than dad's (or vice versa). Perhaps other genes on the same chromosome may have mutations that alter the rate of duplication, thus the cells with the active chromosome containing the white gene happen to divide faster than those with the other chromosome active. These could all offer explanations for why some birds have more white than others. And I'm sure there are other explanations.

 

[AquaEyes]

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Were the "blues" you remember "self-blues" or the "andalusian-blue"? The former mutation is recessive, and often called "lavender" to avoid confusion with the latter, which is an incomplete dominant. The lavenders I've seen (in pics....) are pretty much the same shade all over, but the andalusian-blue mutation reduces pigmentation more in the center of the feather than at the edges. The result is that larger feathers have an overall lighter look than smaller feathers...and the feathers on the head are small. The result, from pics I've seen of andalusian-blues, is that there is a darker shading on the head than on the breast and wings -- basically, wherever the feathers have a smaller ratio of center : edge will appear darker. Go here and compare the images of "Blue Duck" and "Self Blue Duck" to see what I mean. If you look at the "Blue Duck" and imagined painting the head white, but leaving the top of the head alone, you can imagine that the bird might look like it had a "black cap" as opposed to a "blue cap."

 

[AquaEyes]

Lo-and-behold, on another thread in here, I found pics of white muscovies with black on the tops of their heads!

Here is the thread. And below are the pics. I NEVER SAW THESE BEFORE!!! Hahahaha...I never cease to learn things on BYC!

 

[rollyard]

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Who really knows? But your queries did remind me of a breeding several years ago; a pure white drake mated to a bronze pied duck. They produced six drakes from memory, three white & three very haphazardly coloured bronze white pieds. The duck I thought did have duclair pattern, but with some white in normally pigmented area. Could she have been d/d, P/p+ (or D+/D+, P/p+ even)? Were the very haphazard pied ducklings the product of P/p+, & the white P/P? I have no idea what was hidden by the drakes white!

Mother Duck (both side views)

And ducklings

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My blues were made on the incompletely dominant gene, not the recessive self-blue (Lavender). Thanks for desriptions & link which I have seen before. I have found hetero blue to vary in intensity between birds & moults, not to mention fading which occurs as the feather ages. I will certainly look @ blue more closely in the future now though as I have had problems differentiating between Silver, Blue & Lavender in the past

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Yes, they look like the Black Caps I have seen & heard about.

So what do you think the cause of the "Black Cap" pattern? What about a white bird with an additional "pattern" factor (allowing pigmented crown feathers) epistatic to homo incomplete dominant white?