Rumpless genetics

[Veronica V Pinheiro]

Hi, I breed Araucanas (rumpless chicks) here in Brazil and our way of breeding them its different from others standards (I supose) and I would like some help please, I have some questions about the rumples genes. Here we cross tailed birds whit no tail, so we have a mix (we call them ketro and kollonka) but I want to get to the German standard (rumpless and bearded chicks). I talked whit a German breeder and she tells me that theirs birds are always rumpless, they never are born whit tails (maybe one in each five years). Here even if I cross my rumpless rooster whit rumpless chicks we have half of the offspring born whit tails. Can someone share their knowledge on this our point me to a article, book, video anything... thank you so much!

 

[SmiYa0126]

@Kiki thoughts?

 

[Kiki]

@Kiki thoughts?

@Amer

 

[Amer]

Sounds like your birds are heterozygous for the rumpless trait. Rumpless is a dominant trait, so it needs only one rumpless allele to express, but it also has a tailed allele.
Each parent passes down either a rumpless or tailed allele. Some offspring will get a tailed allele from each parent and will be tailed. Some offspring will get a rumpless allele and tailed allele. And some offspring will be homozygous for the rumpless trait, having two rumpless alleles.
To get only rumpless offspring, test breed your rumpless birds against tailed birds to find some that are homozygous for rumpless.
If they produce only rumpless offspring when bred with tailed birds they are homozygous. Then breed the homozygous birds together.

 

[Veronica V Pinheiro]

Sounds like your birds are heterozygous for the rumpless trait. Rumpless is a dominant trait, so it needs only one rumpless allele to express, but it also has a tailed allele.
Each parent passes down either a rumpless or tailed allele. Some offspring will get a tailed allele from each parent and will be tailed. Some offspring will get a rumpless allele and tailed allele. And some offspring will be homozygous for the rumpless trait, having two rumpless alleles.
To get only rumpless offspring, test breed your rumpless birds against tailed birds to find some that are homozygous for rumpless.
If they produce only rumpless offspring when bred with tailed birds they are homozygous. Then breed the homozygous birds together.

Yes thank you so much! I've Ben studying some articles about it and came to the same conclusion, but I read that are some rumples genes that are recessive but I know that it's not my case here. Also I have some question about the homozygous birds, if you have them and could answer me I would be glad. I heard that there are some hatching problems related to the homozygous Rp gene and even some digestive illnesses. Do you agree? Thanks again God bless

 

[Amer]

I have heard this, however, I have no idea if it is true. Certainly, there are reduced hatch rates because rumpless birds have more difficulty breeding but I do not know if it kills birds in the shell or causes digestive illnesses.

 

[JacinLarkwell]

I have heard this, however, I have no idea if it is true. Certainly, there are reduced hatch rates because rumpless birds have more difficulty breeding but I do not know if it kills birds in the shell or causes digestive illnesses.

I haven't found anything between death and rumplessness personally

 

[Altairsky]

This is an old but interesting study on rumplessness
https://www.sciencedirect.com/science/article/pii/S0032579119429684