Citrone Sebright Genetics Question

Discussion in 'General breed discussions & FAQ' started by The Kooky Kiwi, Mar 11, 2018.

  1. The Kooky Kiwi

    The Kooky Kiwi Chirping

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    Hello Everyone

    OK so If I breed my Citrone hen to a Silver rooster her male chicks should receive two copies of Silver (one each from mom and dad) and one copy of Gold (from mom). With two copies of silver I expect them to be dominant silver - but could/would they still show gold leakage?

    The reason I ask.. I have two such males and at 3 months old are starting to show the odd "gold" patch on one or two feathers. Trying to decide if this is gold showing/developing or just dirt :p

    And so, if they do indeed have two silver and one gold gene then am I correct that they have a 50% chance of yielding citrone hen chicks themselves?
     
  2. sylviethecochin

    sylviethecochin Free Ranging

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    I think this is a good explanation, but feel free to tell me it needs clarification. I'm bad at 'splaining. I'm definitely no "The Moonshiner" (He makes genetics simple.)

    Roosters carry two "W" sex chromosomes, which makes them male. "WW"
    Hens carry one W and one Z sex chromosome, which makes them female. "WZ."

    Silver/gold, barred/nonbarred, and chocolate/nonchocolate genes are all located on the "W" chromosome.

    Pullets must inherit the mother's Z chromosome in order to be pullets. Z does not carry gold, barred, or chocolate. Thus, the only copy of those genes that they inherit must be from the father.

    Silver and gold are the same gene. Silver is an allele of gold. The father can only pass one W chromosome, which carries either silver or gold, to his offspring. They cannot inherit two alleles of the same gene from a single parent.

    A silver rooster carries two copies of silver, one on each W chromosome.
    A gold/citron hen only carries one copy of gold, on her single W chromosome.

    The cockerels must receive their mother's W chromosome in order to be cockerels, ergo, they must receive Mum's gold. They must also receive Dad's silver, because that's the only gene he can pass.

    Silver and gold are co-dominant, rather than completely dominant or completely recessive, so cockerels will be lemon/yellow, not gold or silver.

    In short, it's not dirt.

    I can't answer your citron question, though. I don't understand why Citron's not simply gold--I assume that silver sebrights carry a gene that gives gold a different sheen--probably a brown modifier of some sort. If so, then half of your cockerels do have a 50/50 of yielding citron pullets with a gold hen. Don't take my word on this. This last bit is a ramble.

    @The Moonshiner ?
     
  3. The Kooky Kiwi

    The Kooky Kiwi Chirping

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    Hey Sylvie
    Thanks for the reply! I completely understand your logic and explanation and I get hung up on many of the same "logic" questions on this.

    I know that gold hen (W-Gold) to a silver rooster (WW - Silver) yields roosters that are W-Gold / W-Silver and from these roosters we get Citrone hens which are neither silver nor gold but something in between.

    It has been explained in other circles that this effect is "probably" caused by a crossover of the Gold and Silver so that the hen has actually received both. Now I don't know how technically correct this is.. genetically speaking.. but it would certainly explain the colour Citrone if you thought about Silver and Gold both showing equally.

    And that is how I arrived at my Citrone hen having both Gold and Silver on the W allele - to pass on to her male chicks.

    Obviously this needs fact checking though!

    As for my male babies.. that's one of them in my avatar. They are most definitely not "lemon" or any kind of gold in colour. They are a black bird with silver markings. The gold feathers I mention are very few - on the one I checked today I can only see 3 feathers that have gold - and I bathed him just the other day so if it's dirt.. it's permanent dirt! LOL.
     
  4. sylviethecochin

    sylviethecochin Free Ranging

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    Just did some research, actually.

    It's still impossible for hens to receive two copies of a sexlinked gene. If they did inherit it, they'd be roosters.

    Instead, there's a gold inhibitor gene, represented by ig (Inhibitor of gold. Clever, right?). It's recessive, so for the bird to be citron, it has to inherit two copies. (ig/ig). Citron Sebrights are definitely gold birds, but the gold is diluted if they have two copies of the ig modifier gene.

    You'd have to breed the boys back to their mother and see if any chicks come out a lighter shade of gold if you want to breed citron from the original pair.

    EDT: Also, are the yellow feathers on the shoulder? That's usually where they show up in g/s roosters.
     
  5. The Kooky Kiwi

    The Kooky Kiwi Chirping

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    Yup.. I'm following you that she doesn't receive two W genes. I'm saying there seems to be a genetic "crossing over" so that there are both Silver and Gold on the one W gene. This occurs in other bird species - Cockatiels for instance. You can breed a Lutino hen to a Cinnamon male. Male babies from this pair are wild type colour (because neither of these colours will express in the males with only one gene) and carry W-Cinnamon and W-Lutino (Note: Both cinnamon and lutino are sex linked colour modifiers and both act on the grey melanin so behaving similarly to the Sebright scenario). They most definitely exhibit crossover because a percentage of the hen babies are visual Lutino Cinnamon. And I have taken it several steps further by breeding those hens.. they definitely pass both the Lutino and Cinnamon genes (together) to their male offspring. So this is the logic I am using to base my question re: the Citrones - and hypothesising that a Citrone hen can pass silver and gold together to her male offspring.

    Regarding the ig gene - if that gene was randomly present in the population then you'd see a lot of gold/gold sebright pairings resulting in citrone babies.. but this doesn't occur so doesn't seem as likely..

    Re: Your Edit :D On one baby roo the feather is on his back in his shoulder blade area (between wings) and the gold colouring affects the left half of the feather (so not a lace or mottle if that makes sense). On the other baby roo the feather is in his wing and again it is one side of the feather that is affected.
     
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  6. The Kooky Kiwi

    The Kooky Kiwi Chirping

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    Sadly.. I lost my Citrone hen to an illness (I was gutted!!) so my plans to do exactly as you suggest, and breed son to mom, cannot be done now :confused:
     
  7. sylviethecochin

    sylviethecochin Free Ranging

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    ig's not present in most populations. It's pretty rare, and according to one source (can't find it now...) they bred a few Sebrights back to Citron Hamburgs to get it. Crossover happens (during meiosis I, I believe? It's been a while, I'll have to consult my old textbooks) but as I understand it, it's almost always switching genes, rather than adding them. Bad things often happen when you add genes in diploids, according to my old Developmental Biology professor.

    "The Europeans report that Citron/Lemon is a Buff further diluted with the Inhibitor of Gold, the genome is suggested as eb/eb s+/s+ Co/Co Db/Db Pg/Pg Di/Di ig/ig Cb/Cb
    ig is rare in Australia but may be in some Tasmanian bred Campines
    David"


    There's a few other sources, but that one seemed the most reliable. Also, this site is a good color calculator, though the pictures are a bit unreliable.

    Just saw your post. Sorry about your hen.

    EDT: Gold x Silver doesn't get citron, according to my research. You just get sexlinks, like hatchery production birds.

    Again, sorry about your hen. Can you replace her at all? I always thought Sebrights were so pretty...
     
    Last edited: Mar 12, 2018
  8. The Kooky Kiwi

    The Kooky Kiwi Chirping

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    Re: your edit.. my understanding was that gold x silver yielded roosters which were S+/S and G/G+. It is from those roosters that you get citrone hens. And it is my understanding that you never get citrone roosters.

    If there was a recessive gene at play that, when received correctly, could yield a citrone then surely you could also achieve citrone roosters??
     
  9. sylviethecochin

    sylviethecochin Free Ranging

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    [​IMG]
    This is citron; there are both citron hens and roosters. Are we thinking two different colours, maybe?
     
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  10. The Kooky Kiwi

    The Kooky Kiwi Chirping

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    Sadly .. sebrights are not the most common bird here and the few people that have them have reported difficulties rearing the chicks so it's not easy to get reliable birds. A lot of the ones I've seen available lately, I strongly suggest to be barnyard hybrids.

    I still have a very nice unrelated silver sebright and the three babies from my citrone (two males and one pullet), so I'll do a little test breeding with them to see what happens.

    And in the meantime I'll keep trying to put my hand on a quality gold hen or two :)
     
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