Genetics Gurus Please Help! Working Towards True Breeding Olive Eggers

nicalandia

Free Ranging
12 Years
Jul 16, 2009
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Stuck In a Dream
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I see your pea comb and I raise you mine... (mother of my rooster on my avatar) Asil Rajah Murgh from Pakistan

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DarJones

Chirping
Jan 24, 2021
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The legs on Asils always get me. They look so sturdy, especially as compared with leghorns.

How can you ever be sure who has what genetics if all you can base things off of is from trying to reverse-engineer the info?

Genetics is entirely about recognizing small nuances and using them to make breeding decisions. It is also about test mating which - with carefully chosen parents - will tell you whether a dominant gene is homozygous or heterozygous. Sex linked traits require special handling.

Okay, so brown eggs is a biopath. It is NOT a gene - meaning it is not a single on/off gene. A biopath infers a group of genes working together to produce a phenotypic trait. In this case, the trait is porphyrin coating on an egg. There is a lot of information scattered around the net suggesting 12 or more genes involved in the porphyrin biopath. I can't prove this, but my breeding results are strongly suggestive that there are at least 12 and probably more. The thing with a biopath that makes it interesting is that interrupting it at any point may give strange results. Consider Marans that lay dark brown eggs. They have very high numbers of epitheliel cells to produce porphyrin and they line the egg duct further than in other chicken breeds. The result is dark brown eggs. At least 2 of the porphyrin genes are involved in producing the dark brown egg phenotype. Here is where it gets kinky. All chickens have the porphyrin biopath. Some chickens have genes that turn it off resulting in white eggs. If you make a cross that involves a brown egg layer with a white or blue egg layer, you will get brown eggs and because the biopath is present in both parents, it will be very difficult to turn it back off. This mostly has to do with not being able to tell if a rooster has it or not.

What about white eggs, especially Leghorn white eggs? Leghorns have the zinc white gene which makes the eggs extra bright white. Zinc white has a side effect of severely restricting porphryin production. So if you make a cross of any homozygous dark egg layer X a homozygous blue egg layer that has zinc white in the background, you will get very light tan over blue eggs.

Want proof? http://www.selectedplants.com/miscan/Blueeggs.jpg And here are some of the hens that laid these eggs. http://www.selectedplants.com/miscan/slw.blue2.jpg

I've got a lot of work yet to do to stabilize traits. My goal is sky blue eggs so I need to concentrate on blue egg layers and gradually reduce the number of tinted tan over blue.

As others noted, you can get DNA tests done to prove whether your birds have 1 or 2 copies of the oocyanin gene through Justus Liebig University. Caution that there are problems at this time since feathers are not allowed to be shipped into Germany unless they are heat sterilized.
 

NatJ

Free Ranging
Mar 20, 2017
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As others noted, you can get DNA tests done to prove whether your birds have 1 or 2 copies of the oocyanin gene through Justus Liebig University. Caution that there are problems at this time since feathers are not allowed to be shipped into Germany unless they are heat sterilized.
Would the sterilizing mess up the DNA, so the test would then be worthless?
Or is it just one more hoop to jump through in order to get the test done?
 

DarJones

Chirping
Jan 24, 2021
142
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Per the guy who runs the tests in Germany, they trialed heating treating feathers and were able to extract DNA afterwards. As you may guess, temperature is important. Here is a quote from an email he sent a few weeks ago.

We tested heating of feathers in a normal kitchen convection oven, packed in aluminium foil and closed with sterilization tape (for dry air sterilization). If this packages are heated for 150°C for 30 min, the tape will show with color change that there is a successful sterilization. Hence, it can be written on the package "feathers, steriized". We tested DNA extracted from sterilized feathers and it was ok.
 

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