Fibromelanism and crossbreeding

[Alex_Zurago]

I am looking at crossing an oriental fowl roo like an asil or ga noi with an ayam cemani hen. I have heard about how fibromelanism is sex linked and it may not appear in one gender or the other. The other breeds potentially in the cross are bad egg layers, worse than the Cemani, so I would prefer the Oriental gamefowl be the rooster. Would the F1's pullets have black skin, feathers and tissue, what about the cockerels?

 

[NatJ]

The gene for light skin (called Id, for "Inhibitor of Dermal Melanin") is on the sex chromosome. The recessive form (id+) is needed to let the dark skin show.

As a practical matter, this means crossing a dark skinned chicken to a light skinned one will give light-skinned sons, who will also carry the gene for dark skin without showing it. The daughters will match their father for whether they have dark or light skin, and will not carry another other form of the gene.

(The reason: the male has two Z chromosomes, one from each parent. The female has one Z chromosome from her father, and a W chromomsome from her mother. So a hen's Z chromosome, with the sexlinked genes on it, is inherited from her father and passed to her sons.)

 

[Alex_Zurago]

The gene for light skin (called Id, for "Inhibitor of Dermal Melanin") is on the sex chromosome. The recessive form (id+) is needed to let the dark skin show.

As a practical matter, this means crossing a dark skinned chicken to a light skinned one will give light-skinned sons, who will also carry the gene for dark skin without showing it. The daughters will match their father for whether they have dark or light skin, and will not carry another other form of the gene.

(The reason: the male has two Z chromosomes, one from each parent. The female has one Z chromosome from her father, and a W chromomsome from her mother. So a hen's Z chromosome, with the sexlinked genes on it, is inherited from her father and passed to her sons.)

So to get a homozygous for Fm bird you would need a fibro father and an asil hen and then cross the f1s so 1 quarter would come out homozygous for Fm

 

[NatJ]

So to get a homozygous for Fm bird you would need a fibro father and an asil hen and then cross the f1s so 1 quarter would come out homozygous for Fm

I think you're dealing with two genes-- Fm and id+

Oops, it posted before I finished, so I'm editing to finish:

Fm is not sex linked, so it can come from either parent, and then you'd have to either cross F1s or backcross to the fibro parent.

id+ is needed to let the fibro show in the skin, and you can get that in a hen just by having a fibro father. Or you can cross an F1 rooster to his mother or his sister (any hen with id+) to get 50% of each gender showing id+.

 

[Alex_Zurago]

I think you're dealing with two genes-- Fm and id+

Oops, it posted before I finished, so I'm editing to finish:

Fm is not sex linked, so it can come from either parent, and then you'd have to either cross F1s or backcross to the fibro parent.

id+ is needed to let the fibro show in the skin, and you can get that in a hen just by having a fibro father. Or you can cross an F1 rooster to his mother or his sister (any hen with id+) to get 50% of each gender showing id+.

Ok. So how much of the size and body shape would come from the malayoid breeds like the ga noi or asil

 

[NatJ]

Ok. So how much of the size and body shape would come from the malayoid breeds like the ga noi or asil

I'm afraid I have no idea.

But when you cross them, you can see how much shows up in that generation.

And when you do a backcross, or cross F1s with each other, you will probably find lots of variation among the chicks-- so the more chicks you hatch, the better chance you have of finding all the traits you want in a single bird.

 

[Alex_Zurago]

I'm afraid I have no idea.

But when you cross them, you can see how much shows up in that generation.

And when you do a backcross, or cross F1s with each other, you will probably find lots of variation among the chicks-- so the more chicks you hatch, the better chance you have of finding all the traits you want in a single bird.

Why would f2s be more varied than F1s if the F1s have hybrid vigor

 

[NatJ]

Why would f2s be more varied than F1s if the F1s have hybrid vigor

It has to do with the way the genes rearrange.

For example:
Asil have pea combs (genetically PP)
Ayam Cemani have single combs (genetically pp)

So each F1 chick gets P from the Asil parent, p from the Ayam Cemani parent.
Every F1 chicken has Pp comb (looks like a larger, messy pea comb.)

When you cross the F1s together, some each can give either gene to any chick. So some chicks end up with PP, some with Pp, some with pp. That will look like nice pea combs, big/messy pea combs, and single combs.

The same thing happens for every single trait the chickens have.

So you might find one chicken with the right comb type but the wrong skin color, and another who has the right comb and skin color but the wrong size or body type or feather color, and another who has all the traits you do not want, and if you're lucky a few that have the traits you DO want.

When you do a backcross, you get a lot less variation.
For the comb example, when you cross an F1 chicken (Pp) with the pp parent, the chicks can only be Pp or pp, never PP. So you've only got two options in the backcross, as compared with three options when you cross F1s together.

Again, the comb is just one example, but the same thing is happening with every trait the chicken has. So you will still get lots of variation even with a backcross, just not as much as if you crossed F1s with each other.

 

[CBMorgan]

I know someone who has done this already, actually, and I have a few of the chicks. I also researched a bit about their genetics but I may not understand it 100% yet.

If your Ayam Cemani has two copies of the fribro gene the offspring will have one copy and black skin, but may show some white augmentation at the tips of the feathers, down the chest, white toenails or pink toe tips, pads of the feet, inside the mouth, etc. I am waiting to see if my chicks replace their white feathers with black ones after their first molt - like Sumatras do. I don't know yet about the meat, but assume the same - some black meat, some with reduced melanin as I have seen photos of.

Even breeding pure Ayam Cemani to one another this can happen if you don't test breed first to make sure your parents have two copies of the fibro gene. You can find out a bit more about that here if you haven't seen this already: https://ayamcemani.us - Click on "education" and then "articles".

Also, even if your too is the oriental, he will still carry genes for egg production and color, even though you won't know what those are because he is not a hen. If you want better egg layers I would cross first to a high-production hen, back to the oriental a few times and keep only the best layers, then to the Ayam Cemani. Or just don't worry about that aspect or do it after you get the results you want. Either way it will be a long process.

 

[Alex_Zurago]

I know someone who has done this already, actually, and I have a few of the chicks. I also researched a bit about their genetics but I may not understand it 100% yet.

If your Ayam Cemani has two copies of the fribro gene the offspring will have one copy and black skin, but may show some white augmentation at the tips of the feathers, down the chest, white toenails or pink toe tips, pads of the feet, inside the mouth, etc. I am waiting to see if my chicks replace their white feathers with black ones after their first molt - like Sumatras do. I don't know yet about the meat, but assume the same - some black meat, some with reduced melanin as I have seen photos of.

Even breeding pure Ayam Cemani to one another this can happen if you don't test breed first to make sure your parents have two copies of the fibro gene. You can find out a bit more about that here if you haven't seen this already: https://ayamcemani.us - Click on "education" and then "articles".

Also, even if your too is the oriental, he will still carry genes for egg production and color, even though you won't know what those are because he is not a hen. If you want better egg layers I would cross first to a high-production hen, back to the oriental a few times and keep only the best layers, then to the Ayam Cemani. Or just don't worry about that aspect or do it after you get the results you want. Either way it will be a long process.

What did they cross with?