question on genetics feathered shanks naked feet silver hmong

[goedric]

I was reading about the genetics of feathered legs ... and that there are dosage effects... was I could not figure out from surfing was that are feathered feet always associated with feathered shanks... or is there a genotype where the shanks have feathers but there is nothing on the feet?

I have 5 hatched silver hmong... from a fibro farms line.... 3 of the 5 have clean legs and feet... 2 have feathered shanks (front only) and no feathering on the feet whatsoever... so trying to get a grip on the genetics...

Sorry for being a noobie where but i did try to research it and could not find an answer.

Any insight appreciated.

Thx!

 

[Pyxis]

That looks like feather stubs, which is not related to the feathered leg genes. I and others have had it pop up in cemanis. It's also been a thing in Amerauacanas. It can show up on chicks out of clean legged parents. It shouldn't be bred forward, because it's a defect. So birds with it should not be used for breeding.

 

[goedric]

good to know thanks for the info...

 

[goedric]

Okay from what I have been able to find under stubs... is that there is some indication it is partially sex linked showing more often in males... but also appears to be partially dominant... not sure what that means... so i guess its linked to the X chromosome... the only reason i can think of that it would show more in males and be dominant is if there is a dosage effect... assume there are different alleles that confer 2.0 units 1.0 units... and 0.0 units for argument sake... assume expression occurs when a chick has > 1.0 units... so a female could only express with the 2.0 allele... a male could express with a single 2.0 or two 1.0s ... bla bla bla... in this scenario... this hypothetical would appear to be partially dominant and sex linked... of course there could be 10 alleles rather than 3.... hmmm the take away is that some of my clean leg chicks may have the stub gene at 1.0... so i guess since silver hmongs are so uncommon and i have only 5 chicks to work with (plus an older roo I acquired from same line that does not show stubs but could be carrying) I might as well use all chicks that end up being pullets (stubs or not) to build up a population and then work to wind down the presence of the stub genes... or, would that be a mistake... thoughts?

 

[gojira]

That looks like feather stubs, which is not related to the feathered leg genes. I and others have had it pop up in cemanis. It's also been a thing in Amerauacanas. It can show up on chicks out of clean legged parents. It shouldn't be bred forward, because it's a defect. So birds with it should not be used for breeding.

I agree with feather stubs, but i disagree that it is not associated with the feathered leg genes. Every instance of feather stubs i have seen, going back nearly 35 years, has been associated with birds with feather legged breeds in their ancestry. A few years ago I saw a Buff Orpington from an exhibition line with fairly heavy feathering on her shanks, out of clean legged parents, and how long ago was Cochin in the breeding of Buff Orpingtons? I have seen it in Rhode Island Reds, and have seen pictures posted of New Hampshires with feather stubs. I have seen it in other breeds, including bantams, but every case has been a breed with feather legged birds in the ancestry.

 

[goedric]

I agree with feather stubs, but i disagree that it is not associated with the feathered leg genes. Every instance of feather stubs i have seen, going back nearly 35 years, has been associated with birds with feather legged breeds in their ancestry. A few years ago I saw a Buff Orpington from an exhibition line with fairly heavy feathering on her shanks, out of clean legged parents, and how long ago was Cochin in the breeding of Buff Orpingtons? I have seen it in Rhode Island Reds, and have seen pictures posted of New Hampshires with feather stubs. I have seen it in other breeds, including bantams, but every case has been a breed with feather legged birds in the ancestry.

then why no feathers on the feet whatsoever... anyway you may be right... this particular source claims they are different... and that the sb-1 and sb-2 genes were discovered in Rhode Island Reds in 1990... http://www.edelras.nl/chickengenetics/mutations2.html

 

[gojira]

Okay from what I have been able to find under stubs... is that there is some indication it is partially sex linked showing more often in males... but also appears to be partially dominant... not sure what that means... so i guess its linked to the X chromosome... the only reason i can think of that it would show more in males and be dominant is if there is a dosage effect... assume there are different alleles that confer 2.0 units 1.0 units... and 0.0 units for argument sake... assume expression occurs when a chick has > 1.0 units... so a female could only express with the 2.0 allele... a male could express with a single 2.0 or two 1.0s ... bla bla bla... in this scenario... this hypothetical would appear to be partially dominant and sex linked... of course there could be 10 alleles rather than 3.... hmmm the take away is that some of my clean leg chicks may have the stub gene at 1.0... so i guess since silver hmongs are so uncommon and i have only 5 chicks to work with (plus an older roo I acquired from same line that does not show stubs but could be carrying) I might as well use all chicks that end up being pullets (stubs or not) to build up a population and then work to wind down the presence of the stub genes... or, would that be a mistake... thoughts?

There is no X chromosome in chickens. Do you mean z or w? Also, I am not sure about feather stubs being sex linked, as I have seen in it males and females, probably equally. Your take on a dosage effect is not sure right. If you mean incomplete dominance, think the blue gene, or dominant white gene. Personally, I would only breed clean legged individuals. I would try to increase the numbers, and eventually remove any birds who have offspring with feather stubs.

 

[gojira]

then why no feathers on the feet whatsoever... anyway you may be right... this particular source claims they are different... and that the sb-1 and sb-2 genes were discovered in Rhode Island Reds in 1990... http://www.edelras.nl/chickengenetics/mutations2.html

Feathered legs/shanks/toes is not well understood. In the link you provided, it mentioned people feel feather stubs may be polygenic. To me, that makes the most sense. I think feathered legs in general are the result of many genes, not just one. I think the gene(s) for feather stubs are a part of that.

 

[goedric]

There is no X chromosome in chickens. Do you mean z or w? Also, I am not sure about feather stubs being sex linked, as I have seen in it males and females, probably equally. Your take on a dosage effect is not sure right. If you mean incomplete dominance, think the blue gene, or dominant white gene. Personally, I would only breed clean legged individuals. I would try to increase the numbers, and eventually remove any birds who have offspring with feather stubs.

haha yes... z w mammal bias showing... no i do not mean incomplete dominance in the BBS way... alleles of course code for proteins/enzymes that do certain things... often there is a threshhold that must be met before a result occurs... there can be any number of alleles coding for a particular protein with different levels of efficiency... two alleles may be additive ... so the net result is the sum of efficiencies... the BBS system is very simple of course but many traits are not discrete and involve dozens of genes... my example was a hypothetical relatively discrete mendelian model that approaches quantitative inheritance.... if 1.5 units are needed to get feathers... one allele (dominance) is only enough if its the stronger allele.... the 2.0 rather than the 1.0.... but 2 1.0s would express as well.... i am NOT saying this is real... just possible... the literatire on stubs also stated that quantitaive inheritance may well be involved...

Anyway, you are right the cleanest approach would be to cull all stubs... BUT relying on 2 birds to rebuild a population may be throwing he baby out with the bath water... i still think in would rather use the two extra birds and then work to be rid of the stubs from a larger gene pool

 

[goedric]

BUT... Gojira.... maybe you are right and I should get more stock from the same line (since i cant find any other lines so far) and add birds with no stubs (may be harboring) at lease it could be closet to where i want to be than using birds with stubs right! half a problem is better than a whole problem