White Crested Black Polish Question

[Amer]

In my previous comment, I included examples of offspring from a white crested black polish hen that I suspected was carrying mottle. I bred the hen to a tolbunt male to test my suspicions. Some offspring hatched with mottle, and some did not. It was a small hatch, but the results were roughly 50% of each. This confirmed my suspicion that the hen had one allele of the mottle gene. All offspring had a white crest. The Tolbunt that I used for test breeding was bought directly from a line that was created using only gold laced polish and Russian Orloff chickens. There was no Houdan in the bloodline, so the tolbunt contributor did not have the gene for a white crest. This means that the white crest on all of the offspring came from the white crested black parent. This confuses me because any other mix I've done or seen that only had one white crested parent did not result in a white crest.
If the white crest was a recessive allele of mottle, wouldn't the offspring need this particular allele from both parents to express? And how can both mottle AND white crest express on the same bird of they are alleles of each other? Mottle is recessive and must have two copies to express, but if the white crest is an allele of mottle, then a chicken with a white crest would only be able to have one mottle gene, and thus mottle shouldn't express mottle on the body.

@nicalandia suspects that heterozygotes of white crested and European mottled would produce white crested and mottled birds, province that they are incompletely dominant over each other. Correct?

 

[Amer]

I believe that the cross of Mottled Polish with WC Polish will produce intermediate pattern(very small amount of mottling on the F1) and due to the allelic nature of mo^wc one can't have a full mottled polish with a full White Crest.

The feathersite has this hen posted as white Crested Mottled, but I believe that this he is actually mo/mo^wc F1 cross

^^^

 

[Sullys Island Farm]

That makes sense.

 

[Sullys Island Farm]

I believe to test this theory, the F1 offspring from a mottle bred to a wc black would need to bred to mottled and bred to white crested black. If the white crest is an allele of mottle and is neither dominant nor recessive to European mottle, then I would expect to see some lightly mottled offspring with a white crest along with some mottled offspring with a black mottled crest when an F1 is bred to a mottled bird (like Houdan or Tolbunt). Also, I would expect to see some offspring that are white crested black without mottling, as well as some offspring that are white crested with light mottling when an F1 is bred to a white crested black chicken.

 

[Chang1993]

@Sullys Island Farm
Thanks for the upload. Your birds are awesome looking. I was hoping to get of that, so today I bought a broody silkie to incubate my Ayam Cemani x WCBP and my Ayam Cemani x Turken eggs. She currently sitting on half and half, so when they hatch I will bred them together hoping to get 2 male from each with some black skin like their Ayam Cemani father.

 

[nicalandia]

@nicalandia suspects that heterozygotes of white crested and European mottled would produce white crested and mottled birds, province that they are incompletely dominant over each other. Correct?

Correct, for example the e allele mutations eb and Wheaten, most of the time the eWh/eb heterozygotes look intermediate in chick down and adults, but sometimes they lean more to one side of the parents, this is due to other genes that are not known.

White Crest is completely recessive to none white crest/none mottled(for example when bred to black crest black polish), but it will express fully or partially when bred to mottling, also the mottling may show partially or not expressed depending on other factors

 

[shanadienne]

Correct, for example the e allele mutations eb and Wheaten, most of the time the eWh/eb heterozygotes look intermediate in chick down and adults, but sometimes they lean more to one side of the parents, this is due to other genes that are not known.

White Crest is completely recessive to none white crest/none mottled(for example when bred to black crest black polish), but it will express fully or partially when bred to mottling, also the mottling may show partially or not expressed depending on other factors

Apologies for necroposting but it took me a lot of googling to find this thread and it's exactly what I was looking for!

Has anyone done more work/research/breeding in the past four years to confirm the hypothesis that white-crested is allelic to mottling?

I have a white-crested blue polish hen and I may breed her with a speckled sussex rooster next year. Now I'll be looking for some partial mottling in the offspring.

 

[Amer]

I would like to point out that these are my observations and have not been verified by proper genetic research.

I believe that the White Crest color in Polish(as in White Crested Black Polish and the White Crested Red Polish) is independant of e allele(can be had in many e allele backgrounds for example Extended Black, Birchen, eb brown), and is not a new mutation of the Cr incompletely dominant crest mutation.

I believe that what gives the White Color to the crest is an allelic mutation of the Mottling m allele, it's recessive in nature(recessive to Mo+) and I propose the gene symbol m^wc caused by an Endothelin Receptor B2 (EDNRB2) mutation, recently a Japanese team of research was able to identify and new mottling m allle mutation that is responsible for the white color of the Minohiki Japanase breed, they have assigned to that new mutation a gene symbol mo^w(for recessive mottling White Pattern), when they cross mo^w/mo^w parent with recessive mottling mo/mo parent the result shows a Mottling like pattern(looks very much like exchequer pattern)

Here is a recap of the research done by my friend Sigrid(she did the recap but the research was done by a Japanese team) http://www.chickencolours.com/New mottled allele.pdf and the research team work: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0086361

So the Mottling m allele seem to be prone to allelic mutations(just like dominant white i+,I, I^D, I^S), so far only two have been properly documented but I believe there are at least 5 mutations(Mo+, mo, mo^w, mo^wc, mo^e, the last is for the exchequer pattern that used to be called pied but research has atleast confirm that it is the same or allelic to mottling), I believe that genetic mapping of these patterns(White Crest and Exchequer) need to be done to properly identify these mutations.

WC Polish chicks display a mottled like chick down( White Head and white feather tips like Tolbunt Polish before they moult to adult feathers)View attachment 1903439



I believe that the cross of Mottled Polish with WC Polish will produce intermediate pattern(very small amount of mottling on the F1) and due to the allelic nature of mo^wc one can't have a full mottled polish with a full White Crest.

The feathersite has this hen posted as white Crested Mottled, but I believe that this he is actually mo/mo^wc F1 cross

Look at how much mottling is concentrated on the head of this d'Uccle.

 

[Amer]

I wonder if the mottling gene mutated slightly to give that expression.