Genetics questions boggling my mind!!!

[Goosey Girl]

I am a novice to genetics, but trying to make some sense of this. I have a goose (Miss Lemon) who came from a white Sebastopol goose and a Pomeranian Saddleback gander. Miss Lemon mated with a lavender Sebastopol gander (Onslow).

If Saddleback falls into the gene category of pied (Sp or sp) and this is a recessive trait, then I would think their offspring would be 'ZZ Sp sp' for the male goslings and 'ZW sp' for the female. That would mean that the males would be "split for pied" and the females would be visually pied. In other words, only the female goslings would have a Saddleback. The males would carry the trait. ?????
IF this is correct, then why is 8-week old Lemonade (Miss Lemon and Onslow's female gosling) missing her saddle????

One black tip feather does not a saddle make!!! Please, could someone knowledgeable in this subject tell me where my logic has failed?

Is Saddleback autosomal and if I have a male offspring from Miss Lemon and Onslow and breed that boy with Miss Lemon next year, would that provide the means for a Saddleback trait to reappear?

I know this may seem trivial, but I am really curious about this subject. Also, if anyone can recommend any literature on waterfowl genetics it would be greatly appreciated.

One final scenario question. I also have a buff Sebastopol gander (Hyacinth). Would it be out of the lines of genetic rules to think it possible to someday have a visually buff Saddleback, if a female gosling came from Hyacinth and Miss Lemon??? If so would that be 'ZW g sp'?

Thanks in advance for any clarification on the subject. I've read Pete55's posts on genetics and the posts on chicken genetics. Oh boy, this is a hoot!!!

 

[NatJ]

I have a goose (Miss Lemon) who came from a white Sebastopol goose and a Pomeranian Saddleback gander. Miss Lemon mated with a lavender Sebastopol gander (Onslow).

If Saddleback falls into the gene category of pied (Sp or sp) and this is a recessive trait, then I would think their offspring would be 'ZZ Sp sp' for the male goslings and 'ZW sp' for the female. That would mean that the males would be "split for pied" and the females would be visually pied. In other words, only the female goslings would have a Saddleback. The males would carry the trait. ?????

You are right that sex-linked traits in geese are on the Z chromosome. (Also true for chickens and ducks and I think all other birds.)

But a female gives her Z chromosome to her sons, and her W chromosome to her daughters. So a sex-linked trait can never pass from a mother to her daughter, because the Z chromosome never goes from mother to daughter.

 

[Goosey Girl]

You are right that sex-linked traits in geese are on the Z chromosome. (Also true for chickens and ducks and I think all other birds.)

But a female gives her Z chromosome to her sons, and her W chromosome to her daughters. So a sex-linked trait can never pass from a mother to her daughter, because the Z chromosome never goes from mother to daughter.

Ahhh! So my male gosling (Bruce Lee) from the same cross should/could have a saddle. Interesting! THANKS! I will have to see...Bruce is only 19 days old, but the coloring of his fuzz is exactly like that of the Saddleback mix when they were that age!! Who would have thought science could be so exciting!
Bruce Lee's photo:

 

[NatJ]

Ahhh! So my male gosling (Bruce Lee) from the same cross should/could have a saddle.

He certainly got one Z chromosome from his mother, and one from his father. So it comes down to which genes are dominant and which are recessive.

Bruce is only 19 days old, but the coloring of his fuzz is exactly like that of the Saddleback mix when they were that age!!

I have read that some white geese show the saddleback pattern in their down as hatchings, but grow up all white. I will definitely be curious to see how he grows up

Who would have thought science could be so exciting!

I agree

 

[Pyxis]

So, white in geese is Pied plus sex-linked dilution. So from mom's parentage, we could expect her genotype SHOULD look like this: sd+- spsp bl+bl+ G+-

Pied isn't sex linked, itself. Now, her mated to a male lavender Sebastopol, each of her offspring would get one copy of Pied from her. That's not enough for it to express. So, really you wouldn't be looking at any Saddleback goslings.

Mom actually doesn't have any sex-linked genes, since she wouldn't have inherited the sex link dilution from her mother, either, since that only can pass from mother to son.

So really what you SHOULD get, is all blue goslings, carrying one copy of Pied.

 

[Goosey Girl]

He certainly got one Z chromosome from his mother, and one from his father. So it comes down to which genes are dominant and which are recessive.


I have read that some white geese show the saddleback pattern in their down as hatchings, but grow up all white. I will definitely be curious to see how he grows up


I agree

Thanks!!!!!

 

[Goosey Girl]

So, white in geese is Pied plus sex-linked dilution. So from mom's parentage, we could expect her genotype SHOULD look like this: sd+- spsp bl+bl+ G+-

Pied isn't sex linked, itself. Now, her mated to a male lavender Sebastopol, each of her offspring would get one copy of Pied from her. That's not enough for it to express. So, really you wouldn't be looking at any Saddleback goslings.

Mom actually doesn't have any sex-linked genes, since she wouldn't have inherited the sex link dilution from her mother, either, since that only can pass from mother to son.

So really what you SHOULD get, is all blue goslings, carrying one copy of Pied.

Pyxis, thank you. You obviously have a great grasp of genetics! Could you please weigh in on a few other items?

1. To improve my chances of having a saddleback next year, would mating Miss Lemon to one of the goslings improve the chance and of those potential offspring would the ZZ or ZW probability be greater?

2. My other gander is buff. (I have a buff female, but no fertile eggs this year...she is now only 1 year old). Of the remaining eggs in the incubator, all have either the lavender or buff gander as the male. Is it genetically possible that any of these goslings could be buff? I think a female gosling from a buff gander x Saddleback goose would have a 25-50% chance of being buff, but definitely no male buff goslings????

Here is a photo with the lavender male, on left and buff male on right. Miss Lemon is the closest center female in the foreground with 2 other females behind her...

 

[Pyxis]

1. To improve my chances of having a saddleback next year, would mating Miss Lemon to one of the goslings improve the chance and of those potential offspring would the ZZ or ZW probability be greater?

Yes, if you bred her to one of her sons, then those offspring would have a 50/50 chance of being Saddleback. I'm not quite sure what you mean about the chromosomes though. Pied is not sex linked, so it doesn't matter whether the goslings are male or female, as far as their chances of being Saddleback.

2. My other gander is buff. (I have a buff female, but no fertile eggs this year...she is now only 1 year old). Of the remaining eggs in the incubator, all have either the lavender or buff gander as the male. Is it genetically possible that any of these goslings could be buff? I think a female gosling from a buff gander x Saddleback goose would have a 25-50% chance of being buff, but definitely no male buff goslings????

Buff is sex-linked recessive. So yes, for sure no male buff offspring. All female goslings fathered by him would be buff. All male offspring will not be, but will be carrying it.

 

[Goosey Girl]

That is great information, Pyxis! Will be interesting to see if it works out that way. This little bugger hatched yesterday from a different saddleback goose who only allowed the buff gander to mate with her. The darker feathers are really quite orange. Based on your clarification about buff color, I would presume this gosling is a female? We will vent sex them tomorrow.

I really appreciate your insight and I plan to continue keeping records of breeding. There does not seem to be that much information out there about goose genetics I am hoping to some day have something useful to add!

 

[NatJ]

There does not seem to be that much information out there about goose genetics

Did you already find this thread?
https://www.backyardchickens.com/threads/our-guide-to-colour-and-pattern-genetics-in-geese.561779/

It seems more thorough than anything else I've been able to find. (Although it says saddleback/pied/spotting is caused by a gene on the Z sex chromosome, and @Pyxis says saddleback is not sex-linked, so I don't know who to believe.)