Fawn CFW genetics questions

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Majd
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Fawn CFW genetics questions

Post by Majd » Sun Aug 23, 2015 5:24 pm

Hey folks...
I was wondering about this for a while and couldn't really find a straight answer reading everywhere... So i thought I'd just ask. So i know all basic genetics. And that boths fawn and cfw are sex linked genes, but if a male carries those tow genes, i guess his genotype should be as follows: NG/ Fawn-CFW.
Right? But would he be normal grey? Fawn? CFW? Or a combination of boths? Because if a male is only split to either fawn or cfw he would be normal grey. Right? And if he has tow of each ( cfw or fawn) he would be one of the tow colors. Right? But what if he has one of each (one cfw and one fawn), would they both be expressed? Would one be expressed being dominant over the other? Or one of each gene wouldn't be enough to either to be expressed and he would be colored normal grey?
Is it clear enough now?
So tell me what you know and think!

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lovezebs
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Re: Fawn CFW genetics questions

Post by lovezebs » Sun Aug 23, 2015 10:38 pm

Majd

Our Cindy, would know these things. Maybe send her a PM, if no one else comes up with an answer for you.

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Re: Fawn CFW genetics questions

Post by Majd » Mon Aug 24, 2015 3:01 am

lovezebs

Thank you i will!

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cindy
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Re: Fawn CFW genetics questions

Post by cindy » Mon Aug 24, 2015 10:49 pm

from efinch.com Combinations
"The Chestnut Flanked White mutation is part of a multiple allelic series. What this means is that the CFW mutation shares the same location (loci) on the chromosome with the Lightback mutation and both varieties of CFW. They are all variations of the same mutation starting with the Regular CFW. Since they have the same chromosome location, they cannot be combined. Females are either CFW of one variety or another or Lightback. Males can carry the Lightback gene on one sex chromosome and CFW on the other. These birds will be Lightbacks as it is dominant to both forms of CFW, but will be visually different from birds that carry a Lightback gene on both chromosomes. Males can also carry one gene for each variety of CFW, as described above.

The combination with fawn requires a genetic phenomenon known as crossing over to occur before CFW and Fawn can be combined. Crossing over is a random occurrence so one cannot predict how long, if ever, before the combination will occur. Fawn-CFWs look similar to gray series CFWs, but all the black markings will be dark brown instead. Once combined the two mutations are linked and will act as one. Some sources have erroneously indicated that the Continental CFW was a combination of CFW and Fawn. This error is probably due to a belief that the cream cast to the back was caused by the Fawn mutation rather than the new mutation. There is also some evidence that points to a modifier gene that causes a cream cast to the back of Regular CFWs that is more commonly seen in CFW-Fawns. Again, this should not be confused with the Continental CFW mutation."

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Re: Fawn CFW genetics questions

Post by Aspen » Tue Aug 25, 2015 2:00 am

Majd,
He will appear normal grey. The Fawn and CFW are on different genes on the sex chromosome so where he carries Fawn gene, he has one Grey gene which will be expressed, and where he carries CFW, he has one normal gene which will be expressed.

That said, he can only have fawn or CFW female chicks. No grey hen chicks. His male chicks will depend on what he is bred to.

I have a NG appearing male who carries fawn and lightback (which is a variant of the same gene as CFW). He throws fawn and lightback hens.

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Re: Fawn CFW genetics questions

Post by Majd » Wed Aug 26, 2015 8:02 am

cindy thanks for the input!

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Re: Fawn CFW genetics questions

Post by Majd » Wed Aug 26, 2015 8:04 am

Aspen ! That was really helpful! Finaly someone spoke and said that fawn and CFW are on different loci on the sex chromosome Z !!! Thank you that made everything logical now!

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Re: Fawn CFW genetics questions

Post by cindy » Wed Aug 26, 2015 11:09 pm

I own males that carry both :few and ccfw...the give off either hen ccfw and or ccfw hens and gray males split to ccfw and cfw if not paired with a visual cfw or a visual ccfw hen. This will also be the case if the male carries both cfw and fawn.

you can also have a visual cfw male split to fawn or visa versa.

fawn, cfw, ccfw and light backare sex linked and only males will carry the gene and can be split to sex linked mutations.

Hens are only visual and do not carry the sex linked gene nor can they be split to a sex linked mutation. Visual hens (ccfw, ccfw, lightback or fawn) will however give split to a sex linked mutation sons if not paired with a visual or split to a sex linked mutation male.

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Re: Fawn CFW genetics questions

Post by Aspen » Thu Aug 27, 2015 2:02 am

You are welcome, Majd. That genetics course I took still comes in handy sometimes!

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