Colour genes and sex

[Chicalina]

No, it was the feather colour. Obviously I've got the wrong end of the stick somewhere!

Could be you were thinking of the fibromelanism being sex linked when a silkie is crossed with orange/yellow legged birds? So was not feather color, but rather skin/shank color you were remembering?
Would not work with your little polish cross chick though.

I've just read this. How interesting!!!

Post in thread 'Fibromelanism and crossbreeding' https://www.backyardchickens.com/threads/fibromelanism-and-crossbreeding.1470842/post-24569755

 

[Chicalina]

@NatJ Hope you don't mind me tagging you. I just read your comment on the other thread (see post above) and I remember how knowledgeable you are.

This wasn't quite the case for my silkie rooster. He threw 2 pink legged cockerels, and 1 grey legged cockerel with a yellow legged mother (SBLW) and 2 fibro cockerels and 1 fibro pullet with a grey legged mother (GLP). Ok, I get that the fibro from the rooster and the grey from the GLP mother is probably two copies of the dark skin gene, that would make sense.

His new baby is with the same grey legged mother as the one before. Baby is fibro. That means it is no way a sex link leg colour, right?

I wish I understood this better!

 

[NatJ]

@NatJ Hope you don't mind me tagging you. I just read your comment on the other thread (see post above) and I remember how knowledgeable you are.

This wasn't quite the case for my silkie rooster. He threw 2 pink legged cockerels, and 1 grey legged cockerel with a yellow legged mother (SBLW) and 2 fibro cockerels and 1 fibro pullet with a grey legged mother (GLP). Ok, I get that the fibro from the rooster and the grey from the GLP mother is probably two copies of the dark skin gene, that would make sense.

His new baby is with the same grey legged mother as the one before. Baby is fibro. That means it is no way a sex link leg colour, right?

I wish I understood this better!

I've read what the genetics literature says (about dark skin being sex-linked), but I've seen several people posting examples of chicks where it did not seem to work right.

By now, I'm getting confused too!

If your silkie cockerel had dark legs, and you crossed him to a yellow legged mother, then all cockerel chicks "should" have light legs (yellow or white/pink), with female chicks having dark legs (blue/slate/green/willow/black). Obviously, that does not explain your grey-legged cockerel chick.

 

[NatJ]

Am I misremembering this odd colour gene autosexing? I'm sure it was something to do with dominant or recessive white but I don't understand it.

You are probably thinking of gold/silver sex linkage.

Silver (white) is dominant over gold (brown/red/yellow). This gene is on the Z (sex) chromosome.

A male chicken has two Z sex chromosomes, a female has ZW.

So a female gives her Z sex chromosome to her sons, and her W sex chromosome to her daughters. She got the Z from her father, the W from her mother.

So you can cross a gold rooster (two copies of the gold gene) to a silver hen (one copy of the silver gene, one W chromosome that doesn't have any color gene). The sons get gold from their father and silver from their mother, so they look silver. The daughters get gold from their father and W from their mother, so they look gold.

In practice, by the time they grow up, the sons are usually a yellowish silver with red bleeding through in places. But the color difference is clear enough (especially when they are young) that they can often be sexed by color.

These are the genes used in the common Red Sexlink laying hybrids (also called Red Star, Gold Comet, ISA Brown, Gold Sexlink, and many other names.)

But "white" in chickens gets confusing, because there are at least three genes that cause it:

--Dominant White changes black to white (examples: White-Laced-Buff chickens, or White-Tailed-Gold chickens, also some all-white chickens like Leghorns that otherwise have the genes to be all-black.)

--Silver changes gold to white (examples: Silver Laced, Silver Spangled, Columbian, Silver Duckwing). It is the only sexlinked one of the three. You can recognize it because it is the only "white" that shows up with an organized pattern of black (laced, spangled, columbian, etc.)

--Recessive White changes everything to white, like if you whitewashed the whole chicken. It's recessive, so a chicken must inherit it from both parents to show the gene. And when you cross a recessive white chicken to any chicken without recessive white, you get unexpected colors because that "white" chicken still had genes for gold or silver, blue or not-blue, barred or not-barred, columbian or not-columbian, and so forth. You just couldn't see what they were, because the chicken looked all white, but they are still there to get passed on to the chicks.

And of course a chicken can have more than one of these genes for white. Someone recently posted a question about a chick that's white laced silver (they crossed a white-laced-buff to a black-laced-silver, and got white-laced-silver, which just looks white.)

And just to make it more confusing, white barring is caused by another gene yet. (It's also sex linked. Barred mother x not-barred father gives barred sons and not-barred daughters. Black Sexlinks are a common example.)

 

[Chicalina]

If your silkie cockerel had dark legs, and you crossed him to a yellow legged mother, then all cockerel chicks "should" have light legs (yellow or white/pink), with female chicks having dark legs (blue/slate/green/willow/black). Obviously, that does not explain your grey-legged cockerel chicchick.

The grey legged chick was a blue, from a splash mother if that helps?

 

[Chicalina]

You are probably thinking of gold/silver sex linkage.

Silver (white) is dominant over gold (brown/red/yellow). This gene is on the Z (sex) chromosome.

A male chicken has two Z sex chromosomes, a female has ZW.

So a female gives her Z sex chromosome to her sons, and her W sex chromosome to her daughters. She got the Z from her father, the W from her mother.

So you can cross a gold rooster (two copies of the gold gene) to a silver hen (one copy of the silver gene, one W chromosome that doesn't have any color gene). The sons get gold from their father and silver from their mother, so they look silver. The daughters get gold from their father and W from their mother, so they look gold.

In practice, by the time they grow up, the sons are usually a yellowish silver with red bleeding through in places. But the color difference is clear enough (especially when they are young) that they can often be sexed by color.

These are the genes used in the common Red Sexlink laying hybrids (also called Red Star, Gold Comet, ISA Brown, Gold Sexlink, and many other names.)

But "white" in chickens gets confusing, because there are at least three genes that cause it:

--Dominant White changes black to white (examples: White-Laced-Buff chickens, or White-Tailed-Gold chickens, also some all-white chickens like Leghorns that otherwise have the genes to be all-black.)

--Silver changes gold to white (examples: Silver Laced, Silver Spangled, Columbian, Silver Duckwing). It is the only sexlinked one of the three. You can recognize it because it is the only "white" that shows up with an organized pattern of black (laced, spangled, columbian, etc.)

--Recessive White changes everything to white, like if you whitewashed the whole chicken. It's recessive, so a chicken must inherit it from both parents to show the gene. And when you cross a recessive white chicken to any chicken without recessive white, you get unexpected colors because that "white" chicken still had genes for gold or silver, blue or not-blue, barred or not-barred, columbian or not-columbian, and so forth. You just couldn't see what they were, because the chicken looked all white, but they are still there to get passed on to the chicks.

And of course a chicken can have more than one of these genes for white. Someone recently posted a question about a chick that's white laced silver (they crossed a white-laced-buff to a black-laced-silver, and got white-laced-silver, which just looks white.)

And just to make it more confusing, white barring is caused by another gene yet. (It's also sex linked. Barred mother x not-barred father gives barred sons and not-barred daughters. Black Sexlinks are a common example.)

I'm going to save this and reread it slowly about 6 times!

I understand about the gold/silver sex link and the barred sex link. Would the former be created by a paint rooster over a gold laced? Isn't that the wrong way round. Also doesn't explain the gold laced cockerel that was born from that pairing.

 

[Chicalina]

Also I put the paint and GL in kippen and it just came out with black and white. I've been back through photos (gave the cockerels all away) and previously, this pairing threw a fibro paint cockerel with brassiness on his neck (I thought white but he had a couple of black tail feathers), fibro Gold laced cockerel and fibro black pullet (1 white toenail).

Here is the kippen. I've probably done it wrong.

 

[RoostersAreAwesome]

Also I put the paint and GL in kippen and it just came out with black and white. I've been back through photos (gave the cockerels all away) and previously, this pairing threw a fibro paint cockerel with brassiness on his neck (I thought white but he had a couple of black tail feathers), fibro Gold laced cockerel and fibro black pullet (1 white toenail).

Here is the kippen. I've probably done it wrong.

View attachment 2728610

The father probably has genes other than black and dominant white. Silkies aren’t usually bred true to color.