Clarifying Brown Egg Genetics

[Wildo]

Ok guys this seems best thread to ask my question, I have FBDM roos over my flock, that includes RIR.s Buff Orp, EE's and Jersey Giants,..... will these pairings make babies that lay darker shades of brown and green or will they just be similar to there prospective mothers?

 

[Ridgerunner]

What shade of egg did the rooster hatch from? What shade of egg did his Daddy hatch from? If you know that you have a general idea what egg color genetics he will contribute to the mix. You can get an idea what the hen ix contributing by looking at her eggs, but in both cases that is just a general idea. Both mother and father contribute eggshell color genetics.

Some genes are dominant, some are recessive, and some only work if others are present. It’s how those genes mix and match that determines the actual color and shade, but you will often get something in between the two parents.

Not all Marans or Welsummers have the genetics for really dark chocolate eggs. There are plenty of threads on this forum about people complaining about that. If the person selecting the breeding birds selects for dark egg color, then you will probably get some nice dark eggs. But if they are not selecting for egg shell color, you can get some pretty light eggs.

 

[Wildo]

he came from a 7-8 colored maran egg (all 4 of mine that I kept did Wade Jean lines) have 2 roos and 2 hens but not planning on hatching any of the actual marans out cause possibility of them being brother and sister. But I was wondering if it would make the babies I hatched out from the buff orp and rir lay a darker colored brown. It sounds like there is at least the chance of a darker brown from them if I am reading the comments right

 

[tadkerson]

he came from a 7-8 colored maran egg (all 4 of mine that I kept did Wade Jean lines) have 2 roos and 2 hens but not planning on hatching any of the actual marans out cause possibility of them being brother and sister. But I was wondering if it would make the babies I hatched out from the buff orp and rir lay a darker colored brown. It sounds like there is at least the chance of a darker brown from them if I am reading the comments right

Yes the eggs of the offspring will be a darker brown color than the buff orpington or rhode island red egg color. You can produce more marans by crossing brothers and sisters.

Tim

 

[Ridgerunner]

All breeds were developed by mating father-daughter, mother-son, siblings, or cousins. That’s also how grand champions at shows are developed. Bad genetics will come out but so will good genetics. You just have to watch the offspring and not choose defective birds as breeders.

Of course it is a little more complicated than that. You can check on line breeding or spiral breeding to see a bit on how that is done, but unless your Marans have some really bad genetics you should be OK for a few generations. Just choose your breeders with some care.

Tim’s the expert on it, I’m not, but I’m not convinced that brother-sister is really worse than father-daughter or mother-son. That’s even with full brother-sister, not just half brother-sister.

Editted to add:

Let me clarify what I mean by that. If you are trying to enhance certain traits, like dark eggs, and one of your parents has really good traits, then a parent to offspring cross will help reinforce that trait better than a sibling cross. But if you are just worried about maintaining genetic diversity, I am not convinced a sibling cross is any worse on genetic diversity than a parent to offspring cross.

 

[ChickenCanoe]

...

Since the majority of the brown is deposited last, if the hen lays an egg a little early (it doesn’t spend as much time in the shell gland as normal) less brown will be deposited. That’s why you might occasionally see a practically white egg from a hen that normally lays a darker egg. Something stressed her. But for that to happen over a two week period, something else is going on. I have no idea what.

Time spent in the shell gland will often affect the intensity of color. I surmise the time of day the egg enters the shell gland, perhaps morning or early afternoon will cause a darker egg.

I eliminated the brown from the eggs of the offspring of green egg layers in two crosses using white leghorns. But at the same time the blue was also inhibited. I did not attempt to increase the blue color in future offspring- I stopped the study.

I have experienced 6 different kinds of egg pigmentation
1. blue ( various shades) which is found within the shell
2. white with no pigmentation
3. green which is due to # 1 plus brown pigments on the surface of the shell
4. brown eggs with pigments on the surface ( shell itself is white)
5. tinted eggs that have brown in the shell ( just like a blue egg) with very little or no pigment on the surface
6. If an egg shell is smooth or chalky also effects the color hue

The whole biochemical process of egg pigmentation and the genetics are very complicated. There are a few newer studies out that deal with the genetic and biochemical aspects of egg coloration. I have not taken the time to analyze the new information.

I do what is referred to as meta-analysis with multiple studies- the egg review is a good example of this type of analysis. Making the information more easily understood is a challenge.

But you always do a good job of figuring out things. This diagram will help. Pigment is also added to the mammillary layer in some cases. I have seen this in one of my chickens; the inner shell ( mammillary) same color as outer shell layer (palisade). She was an easter egger- so may have something to do with the blue shell allele and the biochemical process ( just a hypothesis). In other words, she should be producing a blue egg but she is not. Biochemical reactions are rate dependent so if not enough of something is around the chemical reaction switches over to another pathway producing another product. Could be the blue pigment pathway was switched off to produce a small amount of brown pigment (blue pigments are produced from brown pigments). Research indicates small amounts of brown pigment are produced while the blue pigments are being produced and vise versa.




Tim

I have found eggs in my flock where brown pigment was in the mineral layer of the shell rather than just cuticle or slightly lower.

Ok guys this seems best thread to ask my question, I have FBDM roos over my flock, that includes RIR.s Buff Orp, EE's and Jersey Giants,..... will these pairings make babies that lay darker shades of brown and green or will they just be similar to there prospective mothers?

IMO, the genetics of egg color is so complicated. I bred a very dark laying Welsummer hen with a Penedesenca rooster out of a very dark egg. Excited to see the returns, you can imagine I was surprised to see very light brown eggs come out of the pullets.
I suppose that the genes contributing to the egg color actually cancelled each other out.

 

[Ridgerunner]

Canoe, I read somewhere there are 13 documented genes that can effect brown egg shell color plus who knows how many undocumented genes. Some are dominant, some are recessive, some are probably partially or incompletely dominant. One at least is sex-linked. As you said, some will cancel others out, but some may simply be recessive that did not match up with your cross but are still lurking in there for future crosses.

I think the number of possible combinations of those 13 genes is 13 squared or 169 different possible combinations of those genes from the father. The contribution from the mother would be 12 squared or 144 because of the sex linked gene. I think that gives 169 x 144 possible combinations or 24,336 possible combinations but I’m not sure. Maybe some math whiz can correct me.

Because some of those are recessive the actual number of possible tints or shades of brown are going to be reduced greatly, but yeah, I’d say egg shell color can be a bit complicated. To me, that is part of the fun of doing the crosses. See what you actually get. A lot of times you get what you expect but occasionally, like you, you get some surprises.



I have found eggs in my flock where brown pigment was in the mineral layer of the shell rather than just cuticle or slightly lower

That's that palisade layer Tim was talking about a little earlier. I've seen that too.

 

[tadkerson]

Time spent in the shell gland will often affect the intensity of color. I surmise the time of day the egg enters the shell gland, perhaps morning or early afternoon will cause a darker egg.

I have found eggs in my flock where brown pigment was in the mineral layer of the shell rather than just cuticle or slightly lower.


IMO, the genetics of egg color is so complicated. I bred a very dark laying Welsummer hen with a Penedesenca rooster out of a very dark egg. Excited to see the returns, you can imagine I was surprised to see very light brown eggs come out of the pullets.
I suppose that the genes contributing to the egg color actually cancelled each other out.

Most likely a recessive sex linked inhibitor from the rooster if you had a number of pullets ( approaching half) that produced a light brown egg. Autosomal recessive if the number approached 1/4.

With the a larger number of birds it favors a recessive gene- an incompletely dominant autosomal multiple locus paradigm would produce varying egg shades in the hens

Tim

 

[Geneticsnut]

I realize that this thread is a few mos. old but I've been searching for info on a dom. gene for white egg shell color unsuccessfully, so decided to ask here. I've always understood white shell color to be recessive but when I mated my buff leghorn roos to my Welsummers hen, five EE hens and three Marans hens all daughter (11) lay absolutely pure white eggs. Can anyone explain this to me. When I crossed these same roos onto brown and exchequer Leghorn hens, (all yellow shanked) then all daughters had green shanks, so it wouldn't surprise me if these roos have unusual dom. white egg color gene as well. Thanks in advances for any info that someone may have for me.

 

[Lauravonsmurf]

Leghorns carry a dominant gene that shuts off the brown... so even though the crossed chicks have the brown DNA the Leghorn Gene just shuts it off like throwing a switch (the DNA is there just shut off)... now if you crossed the chicks with each other enough you could get a few hens that maybe did not carry that Leghorn gene. On page 2 of the thread there is a link to a paper (I am still reading through it myself as it has allot of info to digest on this) but my understanding as of right now is that the Leghorn gene is dominant and also there are some pesky recessive genes also that shut the browning genes down too in birds. Check out the paper it is really good.