Pure white Sebastopol genetics

[The goose mama]

Are there any labs that are able to test your white Sebastopols to make sure they are in fact pure white and not color carriers?

 

[JRies]

The white dillusion is pretly complicated not sure if this will help or @NatJ might have a idea https://www.backyardchickens.com/threads/our-guide-to-colour-and-pattern-genetics-in-geese.561779/

 

[NatJ]

Are there any labs that are able to test your white Sebastopols to make sure they are in fact pure white and not color carriers?

I do not know of a genetic test, so I think you would be stuck with test-mating.

Are you trying to have a flock of pure whites, that never throws other colors? If so, white females are fine. Any white male that produces 8+ white daughters and no colored ones is probably fine too. The more white daughters he has, the higher the chance that he is fine, but you never have 100% certainty.

The white dillusion is pretly complicated not sure if this will help or @NatJ might have a idea https://www.backyardchickens.com/threads/our-guide-to-colour-and-pattern-genetics-in-geese.561779/

If I'm reading that article right, the genes involved are all on the Z sex chromosome, which does make it simpler. Males have ZZ, females have ZW.

So a white female cannot be carrying any other genes that would be an issue (she must have both the dilution gene and the spotting gene on the only Z chromosome she has.)

A white male might carry all the right genes (dilution & spotting on both Z chromsomes), or he might not (dilution on both Z chromosomes, spotting on one or none of them). Test-mating him to a white female would be the obvious way to tell. He should produce one of these options:
--all goslings white (male has 2 dilution genes, 2 spotting genes)
--all sons white, all daughters show some amount of other colors (male has 2 dilution genes, no spotting genes. This is the combination found in Pilgrim geese.)
--all sons white, half of daughters white, half of daughters showing some amount of other colors (male has 2 dilution genes, 1 spotting gene)

So if the male produces any non-white goslings when mated to a white goose, the answer is obvious.

If he produces 8+ white daughters and no colored ones, he is probably pure for white (both dilution & spotting genes.) No amount of white sons will prove anything, because a white female (dilution + spotting) and a white male (2 dilution genes, any number of spotting genes) should always produce white sons.

A white male can also be tested by mating to a female of any other color. Again, only the daughters are useful for telling the father's genes (same results as above: 8+ white daughters and no colored ones means he is probably pure for dilution + spotting). Sons will be white if the female is dilute (Pilgrim) or colored if the female is any other color.

White males or females might also have the genes that turn normal gray geese into blue or buff geese, but you will never see those effects if they are all white. They only matter if you want to cross whites to other colors.

 

[JRies]

I do not know of a genetic test, so I think you would be stuck with test-mating.

Are you trying to have a flock of pure whites, that never throws other colors? If so, white females are fine. Any white male that produces 8+ white daughters and no colored ones is probably fine too. The more white daughters he has, the higher the chance that he is fine, but you never have 100% certainty.


If I'm reading that article right, the genes involved are all on the Z sex chromosome, which does make it simpler. Males have ZZ, females have ZW.

So a white female cannot be carrying any other genes that would be an issue (she must have both the dilution gene and the spotting gene on the only Z chromosome she has.)

A white male might carry all the right genes (dilution & spotting on both Z chromsomes), or he might not (dilution on both Z chromosomes, spotting on one or none of them). Test-mating him to a white female would be the obvious way to tell. He should produce one of these options:
--all goslings white (male has 2 dilution genes, 2 spotting genes)
--all sons white, all daughters show some amount of other colors (male has 2 dilution genes, no spotting genes. This is the combination found in Pilgrim geese.)
--all sons white, half of daughters white, half of daughters showing some amount of other colors (male has 2 dilution genes, 1 spotting gene)

So if the male produces any non-white goslings when mated to a white goose, the answer is obvious.

If he produces 8+ white daughters and no colored ones, he is probably pure for white (both dilution & spotting genes.) No amount of white sons will prove anything, because a white female (dilution + spotting) and a white male (2 dilution genes, any number of spotting genes) should always produce white sons.

A white male can also be tested by mating to a female of any other color. Again, only the daughters are useful for telling the father's genes (same results as above: 8+ white daughters and no colored ones means he is probably pure for dilution + spotting). Sons will be white if the female is dilute (Pilgrim) or colored if the female is any other color.

White males or females might also have the genes that turn normal gray geese into blue or buff geese, but you will never see those effects if they are all white. They only matter if you want to cross whites to other colors.

This was incredibly helpful to me. This is my first year with whites (who still have small spots)

 

[NEgoosegirl]

This thread was helpful to me too!! I currently have a pair of whites, and I have a lot of questions about the whole color-carrying thing. I hope this is a good place to ask a couple of them!

I've heard that any amount of gray on a white Sebastopol (presumably an adult and not a juvenile) is a sign that the bird is a color-carrier. According to the above, I'm guessing this isn't true, at least for females.
Both of the females I've owned had a tiny, dark-gray "beauty spot." One goose had it on the side of her head and the other on the back of her neck. What would cause this? Incomplete dilution? A fault in the spot gene? Something in the way the genes interact? (Too many questions?!)

And this one I'm sure has been asked a million times, but this amateur is trying to comprehend:
In sexing day-old goslings from white parents, does shading on the bill indicate anything? Both my females had some darker shading at the base of their bill as babies. Does this indicate color-carrying, a female gosling, or nothing?

Thanks! I'd love to hear others' experience and advice!

Here's a pic of my current female when she was newly hatched (note shading in the bill):

 

[NatJ]

I've heard that any amount of gray on a white Sebastopol (presumably an adult and not a juvenile) is a sign that the bird is a color-carrier. According to the above, I'm guessing this isn't true, at least for females.
Both of the females I've owned had a tiny, dark-gray "beauty spot." One goose had it on the side of her head and the other on the back of her neck. What would cause this? Incomplete dilution? A fault in the spot gene? Something in the way the genes interact? (Too many questions?!)

Unfortunately, I don't know.
Even more unfortunately, I don't know who else would know. The person who made that informative other thread hasn't been on the forum in almost a decade.

And this one I'm sure has been asked a million times, but this amateur is trying to comprehend:
In sexing day-old goslings from white parents, does shading on the bill indicate anything? Both my females had some darker shading at the base of their bill as babies. Does this indicate color-carrying, a female gosling, or nothing?

I have read that many white geese can be sexed by color when young. The obvious explanation: females have one dilution gene and one spotting gene on their one Z chromosome, while males of the same kind have two dilution genes and two spotting genes because they have two Z chromosomes.

Here is one source for the color-sexing in goslings of a white breed:
https://www.metzerfarms.com/embden-geese.html
"At hatching time you can be quite accurate in sexing the day olds from their coloration as the gray down in the males is lighter than in the females."

So I would guess that your observation about bill color is related to the down color/gender situation, but I can't be positive because I have no actual experience with them.

 

[NEgoosegirl]

Unfortunately, I don't know.
Even more unfortunately, I don't know who else would know. The person who made that informative other thread hasn't been on the forum in almost a decade.


I have read that many white geese can be sexed by color when young. The obvious explanation: females have one dilution gene and one spotting gene on their one Z chromosome, while males of the same kind have two dilution genes and two spotting genes because they have two Z chromosomes.

Here is one source for the color-sexing in goslings of a white breed:
https://www.metzerfarms.com/embden-geese.html
"At hatching time you can be quite accurate in sexing the day olds from their coloration as the gray down in the males is lighter than in the females."

So I would guess that your observation about bill color is related to the down color/gender situation, but I can't be positive because I have no actual experience with them.

Thanks very much, I appreciate your help! I have very little experience myself. I'm just trying to figure it out--what can be figured out, anyway. Genetics are so fascinating.

 

[Deja_view]

@NatJ I'm just trying to be sure I understand your post correctly.
If I have a white male that is pure for dilution + spotting, he will only produce white daughters no matter what color female he is bred to?
Unless he has the genetics that turn grey to blue or buff. Then he may throw other colored daughters if bred to a colored goose?

 

[NatJ]

@NatJ I'm just trying to be sure I understand your post correctly.
If I have a white male that is pure for dilution + spotting, he will only produce white daughters no matter what color female he is bred to?

To the best of my understanding, yes that is correct.

Unless he has the genetics that turn grey to blue or buff. Then he may throw other colored daughters if bred to a colored goose?

If he is pure for dilution + spotting, I think his daughters would be white anyway.