True or False? Olive egg genetics.

[NatJ]

Wait. So you can DNA test for egg color now?

https://www.silveruddsblue.org/testing-for-blue-egg-gene

 

[nicalandia]

Thanks! I didn't want to argue with it, just to see & understand it

It was a general statement, it would be hard if not impossible to argue against something that has been proven time and time again for the better part of the last 80 years

 

[DarJones]

I don't want to argue with the stated results, I want to understand them. When there is a reported range of 3 to 8 centimorgans between two genes, the implication is that there are about 4 million base pairs in between. Normal genes express over roughly 30,000 to 300,000 base pairs with some larger and some smaller, but most closer to 30,000 than in larger sizes. With 4 million base pairs, there is room for dozens of genes between P and O. Here is one statement I found with a bit of delving. "By linkage analysis, we fine mapped the O locus to a 120 kb region, where four candidate genes of SLCO1C1, SLCO1B3, LOC418189 and SLCO1A2 are located." Note that they found 4 genes in the region that was only 120,000 bases long. They mapped the blue gene to SLCO1B3

Here are some of the articles I am currently reading:
https://www.researchgate.net/public...Blood_Groups_A_E_H_and_P_in_the_Domestic_Fowl

Here is the article by Bruckner and Hutts: https://science.sciencemag.org/content/90/2326/88 From the details, they were working with a single rooster that carried one copy of the oocyanin gene. They documented 2 crossovers in 35 female offspring. There are well known and thoroughly documented effects where crossovers preferentially occur in egg meiosis as compared to sperm. In other words, the female in producing an egg is more likely to include a crossover. Since Bruckner and Hutts were working with a male, there is a strong suggestion that there is a relatively wide distance between P and O. One huge caution, 35 birds is NOT a huge sample and should not be taken as statistically significant. There just are not enough birds to nail down the crossover rate with precision. There are other studies that were large enough and produced results that are more accurate.

Here is an article that details mapping the viral insertion: https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1003183

The article I was reading that stated P and O were adjacent had a chinese author. I have not yet found it but will post it when I do. Meantime, the evidence is very clear that P and O are NOT adjacent, but instead are separated by a rather large region that is more than normally active in terms of crossovers. It appears there are about 20 to 30 genes between P and O. I want to nail down that "20 to 30" number a lot better.

 

[nicalandia]

https://www.silveruddsblue.org/testing-for-blue-egg-gene

Would be interesting to see if this DNA test is able to detect the Chinese Oocyan allelic mutation. The Chinese allelic mutation was an independant event caused by the same retrovirus insertion but on a different insertion site..

 

[nicalandia]

I don't want to argue with the stated results, I want to understand them. When there is a reported range of 3 to 8 centimorgans between two genes, the implication is that there are about 4 million base pairs in between.

The article I was reading that stated P and O were adjacent had a chinese author. I have not yet found it but will post it when I do. Meantime, the evidence is very clear that P and O are NOT adjacent, but instead are separated by a rather large region that is more than normally active in terms of crossovers. It appears there are about 20 to 30 genes between P and O. I want to nail down that "20 to 30" number a lot better.

Its good that you want to find all of those genes, but I think we were trying to answer the Cross over frecuency between P and O and its about 3 to 4 centimorgan, there is about 1% chance of a cross over per centimorgan

 

[TheOddOneOut]

All this gene stuff is going over my head. Continue the discussion, though, because I love trying to make sense of it!
I’ll be seeing the people again next Saturday. What would be a simple way to tell them that their info is false?
A simple explanation?

 

[NatJ]

I’ll be seeing the people again next Saturday. What would be a simple way to tell them that their info is false?
A simple explanation?

So you want a simple explanation of why this is wrong:

When you cross a blue layer with a brown layer, you get green eggs. And if you breed a f1 hen and a rooster of this cross, you can‘t get more green eggs. They are only blue or brown.

"Yes, you can get some green eggs from crossing the F1s.

"If the F1 hen gives the genes for brown, and the F1 rooster gives the gene for blue, you will get some daughters that lay green eggs!"

(Of course I left out lots of details, like blue being controlled by one gene and brown by a bunch of other genes. But it might be enough to show why their original statement doesn't work.)

 

[DarJones]

"If the F1 hen gives the genes for brown, and the F1 rooster gives the gene for blue, you will get some daughters that lay green eggs!"

Don't forget that a small percentage may lay white eggs.


I agree with the statement that there are between 3 and 8 centimorgans between P and O. It helps a great deal to see the numbers of hens that were used to demonstrate the crossover rate. I'm a "numbers" kind of guy meaning I like to see the math behind something.

What is amazing to me is the number of articles available today that were not readily available 8 years ago. Some of them date back 80 years. I searched very thoroughly for genetic information in 2013 and found numerous articles about pea comb linkage with oocyanin but did not see anything that broke down the percentages other than one obviously incorrect statement that it was about 80 centimorgans. I think now that what I read was a typo where someone meant to say 8.0 centimorgans and left out the period. Either that or in my haste to read all I could find 8 years ago, I just stuck it in my mind that it was 80 centimorgans. Either way, the number was incorrect.

One thing that should be emphasized is that there can be more than 100 centimorgans on a single chromosome. The longer the chromosome, generally, the more likely a crossover will occur. Chicken chromosome one - which is where P and O are located - has well over 100% probability of a crossover in each chicken hatched. It won't be detected most of the time because we don't have marker genes that produce externally visible traits.

Thanks to all who contributed to this thread. I love to learn new things. The challenge of finding and reading the information on P/O linkage was thoroughly enjoyable. Now I have even more questions. I'd love to know what else is closely associated with Oocyanin and how the straight comb gene plays into the genome. There is a lot more to read!
[/QUOTE]

 

[nicalandia]

So you want a simple explanation of why this is wrong:


"Yes, you can get some green eggs from crossing the F1s.

"If the F1 hen gives the genes for brown, and the F1 rooster gives the gene for blue, you will get some daughters that lay green eggs!"

I would put it this way: When 75% of the expected progeny wiĺl inherit the Oocyan mutation and most of them will inherit at least one of the brown egg shell genes. The chances of getting green eggs of all shades is pretty high

 

[nicalandia]

I'd love to know what else is closely associated with Oocyan and how the straight comb gene plays into the genome. There is a lot more to read!

Basically Single comb is the result of the following traits: p+/p+, r+/r+

Now the wildtype pea comb allele(p+) has been detected at the end of short arm of the chicken chromosome 1 very close to the Oocyan allele. The linkage is exactly the same, p+ is linked to o+ to about 4 cM.

Pea Comb allele: p+ = Intact SOX5, P = Expansion on intron 1 of SOX5

Oocyan allele: o+ = Intact SLCO1B3, Chilean O = SLCO1B3 Insertion on Intron 5, Chinese O = SLCO1B3 Insertion on Intron 5 but on a different absortion site