Shank Color Pattern of Inheritance- Catalanas

Discussion in 'Exhibition, Genetics, & Breeding to the Standard o' started by farmermama2384, Nov 1, 2016.

  1. farmermama2384

    farmermama2384 New Egg

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    I recently acquired a Standard Bred flock of Buff Catalanas. The issue I'm having is that the "best" rooster in all respects has white shanks, they should be blue/green. I have two cockerels coming up with the correct shank color, but their trueness to type remains to be seen.

    Does anyone know the pattern of inheritance for shank color? If I use the white-shank roo, will he only throw white legs? His type is so good in all other regards. He was recently evaluated by Rev. Roland Romig (the original importer of the breed to the US) and in one breath I was told he was the best rooster I had, and in another breath I was told to cull any white-legged Catalanas. So, now I am at a loss.

    Any advice is much appreciated. To my knowledge, this flock is one of only two listed with The Livestock Conservancy and I am working on increasing their numbers. Thanks!
     
  2. RCleghorn

    RCleghorn Out Of The Brooder

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    You have tackled quite a challenge!!! Type comes first. Always. If he is without a doubt the best typed male you have then use him. Make sure his mates have the leg color you are looking for. Next generation do not keep any white leg birds. Hopefully you can get some nice typed green/ blue shanked birds out. You will have to cull hard on the leg color for a while. Be diligent.

    On another note. We are not breeding kangaroos. They are cocks or cockerels. Correct terminology will get u a lot farther, than calling them roos. Serious breeders do not accept that term very well. Good luck
     
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  3. Kev

    Kev Overrun With Chickens

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    It seems you are dealing with the presence of Id. Id= Inhibitor of Dermal melanin.

    It is a single and dominant sex linked gene. What it does is prevent pigment from being deposited on the dermis layer in the legs.

    A white skinned chicken with Id will have clear white legs.

    A yellow skinned with Id will have clear yellow legs.

    A white skinned chicken without Id will have blue/slate legs.

    A yellow skinned chicken without Id will have green/willow legs.

    Since it is dominant, there is a chance the roo may not be pure for Id, meaning he *might* produce blue/green legged offspring. The only way you will know is by breeding him with a blue/green leg hen. If any blue/green legs shows up it means he is not pure for Id. Any of those blue/green legged offspring are perfectly safe to use, as the Id gene is 100% gone, not present. They will never produce a white or yellow legged bird if bred with blue/green leggers. Problem forever solved in this regard.

    However, if all chicks come up white/yellow legged, that is still allright. Because the sons are definitely not pure for Id if they had a blue/green legged mother and you can choose the best son and breed him with blue/green leg hens. (and you WILL get half blue/green legged offspring in both sexes from this)

    Unfortunately(or maybe it is fortunate, depending on how you look at it) because Id is sex linked, it means ALL hens have Id or not at all, same concept with sex linked barring. So the white/yellow legged hens are not terribly desirable because they will give Id to all of their sons- meaning all of her sons will be yellow/white legged.

    However, you still will be fine with using an awesome blue/green leg roo over a white/yellow legged hen if she is exceptional in some way, because this will produce blue/green leg daughters and those are "perfectly safe" use in a breeding scheme because they do not carry the Id gene in any form. Again, if there is an exceptional son from this, you know he is not pure for Id and you can still use him over blue/green leg hens with the understanding you will have to cull out about half yellow/white leg chicks in both sexes from this.

    Let me know if this was helpful?

    p.s. if this was not clear enough by now... DO USE HIM!! From what people seem to be saying the white legs is practically that roo's only fault and this is an incredibly easy fix.

    p.s.s. White skin is dominant over yellow. It's not sex linked so it does not matter which parent has what. However if you want blue leggers and have an excess of green leggers, you do want to deliberately use a blue legger so the white skin doesn't completely disappear from the stock. Green leg bred to green leg will only produce green leggers. Blue leg to either blue or green leggers are capable of throwing all blues OR a combination of green/blue leggers.
     
    Last edited: Nov 1, 2016
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  4. farmermama2384

    farmermama2384 New Egg

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    Thank you, thank you, thank you! This is exactly the info I was looking for! The flock I salvaged is composed of 4 blue leg pullets, 2 blue leg hens, 2 blue leg cockerels, and the 1 white leg roo (I will never submit!). So, based on what you are saying, the id gene should be stable in the females because blue is recessive and sex-linked? Is that correct? So if they are blue, they are homozygous recessive for the id, and the white leg male might not be homozygous dominant and could carry the recessive. In which case, I would find out based on the leg color of the F1 male offspring? If I did my punnet square correctly, a homozygous recessive female x heterozygous dominant male would yield 50% blue:50% white, but only in the males? Please check me and make sure I am following you.
     
    Last edited: Nov 1, 2016
  5. Kev

    Kev Overrun With Chickens

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    You've got the gist correctly but need to alter it a bit for the fact Id is a sex linked gene.

    If you are aware how barring works and is used for sex linking, that is exactly the same concept. Barred hen bred with RIR gives you the black sex links.. the males get a white head spot and the females don't have this. Pullets grow up non barred, cockerels grow up with barring.

    However if you use a barred rock over a RIR hen, it will not work for sex linking as all chicks in both sexes will turn up with the white head spot. Basically that;s why genes like this are called sex linked- it's located right on the sex chromosomes.

    You know how human females are said to be XX and males XY? The Y gene is much reduced and is missing a lot of space/genes.

    In birds it is reversed- females are "XY" and males are "XX"... they actually used a different pair of chromosomes to turn into sex determining chromosomes.. for this reason they are labeled ZZ and ZW.

    Tried looking for a Punnett square using sex linked genes and didn;t find one right away so I'll try-

    It's simpler to use a negative - for the Y or W chromosome. Like a barred rooster can be BB, Bb or bb but hens can only be B- or b-.

    For a Punnett, you write across the top B - for a barred hen and down the side b and b for an non barred rooster. Your answer should be Bb, Bb, b- and b-.

    Bb is a barred male, not pure for barring and b- is non barred female.

    Now for Id, you use Id- for females, IdId, Idid or idid for males.

    Since he has white legs, he is either IdId or Idid. All of your pullets/hens are id-

    You definitely will find out soon enough with how the chicks legs color up.. if he is Idid then half of them will be blue legged.
     
    Last edited: Nov 2, 2016
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