Mixed genetics and their (dis)advantages

blue/green egg gene is dominant so the first generation of a blue/green egger cross will always give blue/green eggers.
Sooo...

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

View attachment 1064415

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

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
 
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
Outstanding! I'm book marking that.
 
Part of the difficulty in predicting egg color genetics (or any other genetics for that matter) for most people is in the often murky pedigree of their stock. Just because a hen looks like or is sold as a certain breed and lays the appropriate color of egg for that breed doesn't mean the hen is purebred, nor that she is "pure" for that egg color. It just means that color egg is expressed by that hen's genetic makeup. The charts only really work when you can be reasonably certain of the individual genetic makeup of each individual bird. I dare say, with Easter Eggers this is currently impossible. With other breeds it can be much easier, or not. :confused: How well do you know your original stock's genetics?
 

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