Double Splits in Zebra Finches -- CFW and Fawn
Posted: Mon Mar 30, 2015 3:33 pm
Okay, so, I was very perplexed when my zebra pair had a fawn baby, Cecily:
The mum Juliette is a normal grey hen.
The dad Piper is a normal grey male, split to CFW (I'm positive. I bred him.)
I was perplexed when I got a little fawn hen from this pair!
The only answer was that dad Piper had to be split for BOTH CFW and Fawn. But I wasn't sure if this was possible. Both of these are sex-linked genes and I (erroneously) thought that those traits shared the same gene location (this is the case for CFW and Lightback, so you're either/or, not both.)
It was very confusing.
I researched here on the forum and beyond, but I couldn't find an answer.
So I emailed finch god Roy Beckham (eFinch.com).
The answer: A zebra finch male CAN have a double split to CFW --AND-- Fawn.
According to Roy, he can only produce fawn and CFW hens. He cannot produce grey hens. So any greys from this pairing are necessarily male (which is what I suspected anyways.)
Females cannot be split for a sex-linked genetic trait because they only have one Z gene.
(Males are homozygous, ZZ. Females are heterozygous, so they're ZW. So they carry a sex-linked genetic trait on the Z, the W doesn't carry any sex-linked genetic traits.)
So my male Piper is necessarily a NG split to Fawn and CFW. (As is his dad, Molly Sue.)
Mystery solved!
The mum Juliette is a normal grey hen.
The dad Piper is a normal grey male, split to CFW (I'm positive. I bred him.)
I was perplexed when I got a little fawn hen from this pair!
The only answer was that dad Piper had to be split for BOTH CFW and Fawn. But I wasn't sure if this was possible. Both of these are sex-linked genes and I (erroneously) thought that those traits shared the same gene location (this is the case for CFW and Lightback, so you're either/or, not both.)
It was very confusing.
I researched here on the forum and beyond, but I couldn't find an answer.
So I emailed finch god Roy Beckham (eFinch.com).
The answer: A zebra finch male CAN have a double split to CFW --AND-- Fawn.
According to Roy, he can only produce fawn and CFW hens. He cannot produce grey hens. So any greys from this pairing are necessarily male (which is what I suspected anyways.)
Females cannot be split for a sex-linked genetic trait because they only have one Z gene.
(Males are homozygous, ZZ. Females are heterozygous, so they're ZW. So they carry a sex-linked genetic trait on the Z, the W doesn't carry any sex-linked genetic traits.)
So my male Piper is necessarily a NG split to Fawn and CFW. (As is his dad, Molly Sue.)
Mystery solved!