Dominant genes? Egg colors, combs and muffs?

[Muggsmagee]

I have 2 EE pullets with pea combs that lay light brown eggs these are F2's their mom was NH x Wheaten Am while their father was pure White Orpington. I also have 1 bantam EE I got from a friend that is an f1 (bantam ameraucana x millie fleur d'uccle) that has a straight comb that lays a light brown egg. None of this would make sense statistically, would it?

 

[nicalandia]

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No.. but you can't claim this is the norm or it will be the norm right?

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you have about 96% chances that a single combed EE will lay a tinted egg thanks to linkage..

 

[wclawrence]

The simple answer is still to make the cross, and keep the peacombed bearded/muffed ones. Or keep looking for an EE rooster in your area. I guarantee somebody over there has one. heck I have one you can have for free if you want to drive to 30 miles on the other side of atlanta.

 

[PaleMelanesian]

I have some EE mixes of unknown history, but they are probably part Leghorn. Two look like Leghorns but lay tan eggs. Four others are interesting and confuse some of my expectations.

single comb, beard = blue egg
single comb, clean face = green egg
pea comb, clean face = blue egg
pea comb, clean face = brown egg

I was surprised by the results, expecting blue from the pea combs and brown from the single combs. I believe the quoted 96% probability, but in my own flock it's completely off of that mark.

The "single combs" on these two are that funny floppy blob comb you see on some EE's. I'm not sure what to call it, as it's not really either pea or single.

 

[nicalandia]

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well is still probable... do you still have those p+ hens?

 

[Grumpypantsmomma]

So my one pullet her mom being EE laying green eggs, and dad being a Mille Fluer Booted Bantam niether of which have the muffs, and both pure bred, has a 50/50 chance of laying Green like momma or Cream like the Booted bantam. But if i were to breed the Chick to a roo that had brown egg gene, then the offspring have more of a chance of laying tinted/brown.
If I breed her back to an EE Roo that has the Green egg gene then the chances increase of her offspring laying green.
But if i breed her to a Roo with a blue gene, then would I get Blue Green eggs from the offspring or is that entirely different? or would i get mixed variation of the chicks! Like some that lay blue, some green and some tinted?
I don't think i am totally understanding this!

 

[tadkerson]

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When the hen produces an egg and you know the color post again.

Genetics 101

Muffs and beard is dominant- if she carries two of the muffs and beard genes all of the offspring will have muffs and beards ( heterozygous or split). Muffs and beard has a variable expression when heterozygous. It has been my experience that you can have medium to very small muffs and beard. I had one female that did not express muffs and beard and was heterozygous. She had rudimentary wattles as if she had muffs and beard.

If she carries one muffs and beard gene then some F1 ( offspring from the cross) will have muffs and beards and others will not have muffs and beard.


Concerning pea comb and blue egg gene. Crossing over can only occur in birds that are heterozygous for pea comb and heterozygous for the blue egg shell gene.

If a person crosses a purebred blue egg shell/pea comb bird (ameraucana) that is P-O/P-O with a bird that is white egg shell/ single comb p+-o+/p+-o+ (OEG )the F1 will be heterozygous (split) for both traits P-O/p+-o+. The - line represents the two genes being linked.

Crossing over can occur in the F1 individual with a 4 % chance of the crossing over occurring. If this individual is a rooster, about 4 out of every 100 sperm he produces will carry a blue egg shell gene linked with a single comb gene ( p+-O). This bird can pass on the blue egg shell gene and the single comb gene to his offspring 4% of the time.

For every blue egg shell/single comb gene combination produced a white egg shell and pea combed combination will be produced. The offspring have a 4 percent chance of inheriting a white egg shell gene and a pea comb gene.

Any body wanting to produce a single combed and blue egg layer can use the male as the possible crossover individual because males produce millions of sperm while females only produce one egg at a time. Once you have a male, use females that inherit the cross over from the male in future crosses. The only problem with this is that males do not lay eggs- the single comb will be expressed but not the blue egg shell. Not an easy task. Lots of test crossing with the males.

The second way would be to produce hundreds of heterozygous females and cross them with homozygous single combed white shell males. Have fun with that one lots of eggs to hatch and chicks to raise.

Tim

 

[nicalandia]

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Thanks Tim, I never actually thought about using Het O/o males for CrossOver.. but it makes so much sence now

 

[Sonoran Silkies]

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can you elaborate more on this?

When you take an EE (let's assume an f1 in this case crossed from an Ameraucana to a brown egg laying Orpington) and cross back to another brown or cream egg laying breed (OEGB) you further suppress the blue egg gene. If the EE hen is an f2, already a cross from an f1 (use first example) to a brown or cream egger, she could lay a blue/green egg, but her offspring would most likely lay a brown or cream egg based on the OEGB being the father.

Not necessarily. Let's assume she has one copy of the blue eggshell gene, O. She will pass that on to about half her progeny, and the not-blue-eggshell gene, o+ to the other half (statistically speaking--the reality is that EACH offspring has a 50/50 chance of inheriting the blue eggshell gene versus the not-blue eggshell gene, and as Nicalandia said, the linked allele of the pea comb gene will almost always be inherited as well. Paired to a single combed OEGB who is pure for not-blue eggshell, all his offspring will inherit a copy a single comb gene and not-blue eggshell. This means that about half the progeny will have the same genotype, from a blue eggshell standpoint as the mother. The other half will not have the blue eggshell.

You do not reduce the percentages based upon the number of outcrossings if you are always selecting a bird that lays a blue eggshell. Now you may ALSO be breeding in brown egg coating genes, but that is not what you are saying.

 

[Sonoran Silkies]

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In large nummbers of hatchings, the statistics will bear out. But if you think of it as the percentage of probability that a single bird will inherit one way or the other, does it make more sense? And once crossover is achieved, then that result is linked for future offspring.