B^sd B-0 Dilution Barring Question

[Purple_Sully]

If this ends up being a big conversational thread or a show-and-tell thread, I'm totally cool with that as long as the focus is on the barring alleles that cause Dilution and Extreme Dilution.

Anyway, due to the minimal resources online, I'm finding it difficult to decide if my chickens have the B-2 (B^sd) allele or if they have the B-0 (extreme dilution) allele. Which ever of the two my chickens are, why do some end up looking like Spotty Game chickens while others look like typical dilution barred chickens? And some even have random full-color feathers in combination with diluted barred feathers. Is there a modifier that changes the way B-2 and B-0 express? Do different e-locus alleles cause this barring to express differently?

 

[nicalandia]

It's highly unlikely that what you have on your birds is the Sex linked Extreme Dilution B0 Mutation, from research Circa 2017 the mutation has been only isolated on closed lines of production white leghorns, the hen on the picture you posted confirms that. as B0/- females have normal barring pattern as other sex linked mutations,

For more info on female phenotype you can check this: https://www.ncbi.nlm.nih.gov/pubmed/28388616

 

[Purple_Sully]

Thank you for your reply. People have suggested B^sd (dilution barring) for my birds. What are your thoughts in regard to this?

 

[Purple_Sully]

Whatever the gene is, it seems to be sexlinked. Heterozygous males hatch darker than hemizygous females.

 

[nicalandia]

Thank you for your reply. People have suggested B^sd (dilution barring) for my birds. What are your thoughts in regard to this?

I would not rule out B^sd, but I suggest you do an outcross to pure black line instead of keeping a close breeding flock, that will help isolate the gene/s responsible for such diluted effect

 

[Purple_Sully]

The closest I have to black chickens are white crested black Polish that carry mottle.

 

[nicalandia]

The closest I have to black chickens are white crested black Polish that carry mottle.

I guess we will never find out.