Mixed genetics and their (dis)advantages

[Lady of McCamley]

EDITED to add...but God forbid those original birds be called Easter Eggers as that totally convolutes the lineage of the all important blue gene...the original imports, being purified by that Spanish professor, have been and always were known as Araucana from the Chilean region of that name.

 

[Luka Dorkić]

It is very interesting how egg color works.

An egg has a base shell. Genetically it is coded for either blue (some bile thrown into the calcium at the shell gland) or non-blue (no bile pigment included).

Therefore, you have either base white or base blue shells. Most of the base blue was bred out of domestic breeds (being more of a jungle fowl thing), so people are used to seeing the base white shell egg.

About 13 genes are needed to produce the brown wash (hemoglobin) which is added later in the egg tract.

How much brown wash depends upon the genetics in the line. Darker layers, like
Welsummer, Marans, Barnevelder, etc. simply add more brown wash pigment to the egg than the lighter brown layers. With dark brown layers, until the egg dries, you can with your fingernail scrape off the brown wash like paint.

Brown wash over a white shell produces brown toned eggs, varying colors depending upon how much brown the line lays. (Crack open a brown egg, and you will see white shell inside.)

Brown wash over blue eggs produces green eggs. (Crack open a green egg and you will see blue shell inside.)

Brown can be elusive. I purchased a Splash Marans from a 7 scale parentage and got maybe 5 scale...much lighter. I have bred her to a Barnevelder and gotten one daughter who lays darker (about 5) eggs while another daughter lays lighter plain brown.

There can even be brown inhibitors in some lines which promote more of a cream than true brown.

As to the blue gene, it is not so random but mathematical. So mathematical that we get our Punnett Squares from the research done by R. C. Punnett who created Cream Legbars in attempt to provide auto sexing breeds to Britain (and added the blue in for fun from the then new blue layer birds from Chile)....but you have to pay close attention to your breeding or you can easily breed out the blue gene.

There are 2 genes that are allotted for blue. Each parent has a "slot" for that blue gene. If it is a pure breed blue layer, both slots are filled with the blue gene...so 2 blue genes.

Offspring receive 1 gene from each parent. If pure "blue" breeds are used, the offspring will always end up with a set of 2 blue genes...1 blue from each parent. Some funk can of course happen, as can with any genetics, but you can pretty much count on 100% blue egg layers when both parents have 2 blue genes.

Now to get hybrids, such as Easter Eggers and backyard mixes, you are breeding a pure breed parent with 2 blue genes typically to a non-blue gene parent (2 empty or non-blue slots).

The offspring receive 1 gene from each parent. The blue gene parent offers a blue gene each time as they have only blue to give, so the offspring will always receive 1 blue gene. The other parent has no blue gene to offer, so an empty slot.

Blue is dominant. So if the offspring have 1 blue gene and one "non-blue" (or empty slot), then the eggs will be blue.

A bird with 1 blue gene generally produces a lighter blue than those with 2 blue genes.

But what if we breed a hybrid, 1 gene blue (such as an Easter Egger) to a non-blue bird.

That's when the Punnett Square math comes in. You set up the grid of 4 with capital O (blue gene) and little o (non blue gene). The hybrid blue is Oo and the non blue is oo.

Combining the O and o from the blue hybrid with a non-blue bird, you will see that you will statistically get 50% of the blue passed down as 50% of the offspring will (statistically) receive 1 blue gene. Blue is dominant, so light blue layers are created pretty much 100% of the time (although some funk could happen). It feels random as it is statistical math....just as flipping a coin will produce heads or tails 50% of the time, but you may have to flip a few times before the pattern is shown. You could at first flip 10 heads in a row, but over time, you will see the 50/50 pattern.

Breeding hybrid blue back to hybrid blue recaptures your blue genes, and you (statistically) will get 25% dark blue, 2 blue genes; 50% light blue, 1 blue gene; and 25% no blue.....so 75% chance of blue layers, either light or dark.

The brown wash is much, much trickier to track, and is not fully understood. Usually, the rule of thumb is, take a dark parent and breed to a light/white parent, you typically get a shade in between. As stated, I have thus far produced 50/50 of it passing down. My second generations from that first generation dark layer are growing up now and not yet laying, so I'll see what I've got in a few months.

As to your pairing of a Cream Legbar (2 blue genes) to a Brahma (non-blue), you will get 100% pass down of 1 blue gene to all offspring, so lighter blue shells.

Many Cream Legbar also seem to have some brown wash genetically, so you will get some from that side and some from the Brahma side (which lays a brown tinted egg)....so it is pretty certain you'll get green layers of varying shades this first generation.

Take this offspring and breed it back to your Cream Legbar and you will recapture your blue genes. Breed this offspring back to your Brahma and you could lose most of your blue genes unless you very carefully follow and only set green eggs (which puts you back into the 50/50 statistics).

Have fun breeding crosses. I too enjoy the combinations of plummage and egg colors. I've set up my breeding program so that I can see by plummage color what the egg genetics ought to be underneath.

I'm using a red based Barnevelder rooster over Splash Marans (produced blue dark layers); black Isbar/Marans olive egger (produces F2 black dark or olive); and production reds that are producing F1 red birds brown tints and F2 barnevelder types, tints to be determined.

LofMc

Oh wow thanks for posting this! it will surely come in handy.

 

[Luka Dorkić]

View attachment 1064574 View attachment 1064575 View attachment 1064576 @LilJoe A few charts to get you started. Keep in mind that at least two layers are involved in the color of the eggshells as our eyes perceive them. Even the experts cannot seem to agree if certain other factors might be involved, at least in some cases. Cheers!

Interesting, this will come in handy.

 

[NorthTexasWink]

I'll never understand the reasoning of the APA folks with regards to their show standards for a breed with a lethal gene. At least the dog show folks got it right with breeds like the Chinese Crested. You can show either the hairless or the powderpuff versions without penalty. Good thing since you can't breed a hairless to a hairless and get anything but misery.

 

[Wickedchicken6]

I'll never understand the reasoning of the APA folks with regards to their show standards for a breed with a lethal gene. At least the dog show folks got it right with breeds like the Chinese Crested. You can show either the hairless or the powderpuff versions without penalty. Good thing since you can't breed a hairless to a hairless and get anything but misery.

Really? I didn't know that.

 

[NorthTexasWink]

@Wickedchicken6 the CC standard for both hairless and powderpuff is the same with the exception of the coat.

 

[Wickedchicken6]

@Wickedchicken6 the CC standard for both hairless and powderpuff is the same with the exception of the coat.

Oh darn. I'm sorry...I needed to clarify.
I didn't know a person couldn't breed a hairless to a hairless.

 

[NorthTexasWink]

Oh! Yup, generally lethal, tho I've heard people say it sometimes results in a live birth of a weak pup that soon dies. I've not ever personally known anyone to intentionally try the mating. It might be because CC are still rather pricey, and most breeders add sterilization clauses in their conditions of sale for all their pet quality dogs. The hairless ones being less common, no one in their right mind would want to risk their bitch's life or potential reproductive future that way, not to mention the waste of time.

 

[Wickedchicken6]

Oh! Yup, generally lethal, tho I've heard people say it sometimes results in a live birth of a weak pup that soon dies. I've not ever personally known anyone to intentionally try the mating. It might be because CC are still rather pricey, and most breeders add sterilization clauses in their conditions of sale for all their pet quality dogs. The hairless ones being less common, no one in their right mind would want to risk their bitch's life or potential reproductive future that way, not to mention the waste of time.

Thank you for that information. I love the things I learn on here.

 

[chickengr]

Sooo...

View attachment 1064415

...since this pullet is a first gen. cream crested legbar × brahma, she could either lay blue or green eggs?

if your CCL is pure you have got a green layer!

my avatar chick (born 12th feb) is an araucana (roo) mix. I yesterday found 3 of her eggs in her run! I didn't expect her to start laying so early. she is the only (pale) green layer in that run.